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Reconstructing the Early Evolution of the Cupressaceae: A Whole-Plant Description of a New Austrohamia Species from the Cañadón Asfalto Formation (Early Jurassic), Argentina

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Premise of research. A new Early Jurassic species of Cupressaceae is reconstructed from the Cañadón Asfalto Formation in Argentina, based on impressions of foliage and attached and dispersed seed and pollen cones. Methodology. Over 230 specimens were examined using reflected-light microscopy and epifluorescence. Relevant extant taxa were studied for structural comparisons using herbarium specimens and living material from botanical gardens. Relationships of the new conifer were assessed in the context of currently known fossil and living taxa and used to evaluate morphological trends in the early evolution of Cupressaceae. Pivotal results. The new species, Austrohamia asfaltensis D.L. Contreras, I.H. Escapa, R.C. Iribarren, & N.R. Cúneo, has helically arranged, dorsiventrally flattened leaves that are rotated into semiplanar orientation, seed cones consisting of helically arranged coriaceous ovuliferous complexes that each bear two seeds and have a distinct abaxial keel and acuminate apex, and pollen cones that occur in clusters subtended by keeled bracts. Specimens show evidence that normal vegetative shoot growth continues from the pollen cone clusters, a condition that appears to characterize living Cunninghamia and some extinct conifers but not Taiwania. The new species is assignable to the genus Austrohamia, which shares a combination of characteristics consistent with the Cunninhamioideae and Taiwanioideae subfamilies of the Cupressaceae. It is distinct from other Austrohamia species, most notably by having seed cones that are twice as large and with many more ovuliferous complexes. Conclusions. The new species expands the known morphological diversity of Austrohamia, which is the oldest recorded genus of Cupressaceae based on reproductive material, and provides a new early occurrence of the family in the Southern Hemisphere. The development of a whole-plant concept enabled morphological comparisons over a broad range of traits and with taxa known from different combinations of organs, which has provided additional insights into the early evolution of Cupressaceae.
Pollen cones of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov. A-C, Clusters of immature pollen cones at ends of foliage shoots. E-G, Dispersed pollen cones. I, J, Microsporophylls viewed through a compound microscope with epifluorescence. A, Cluster with at least five pollen cones (MPEF-Pb2430b). B, Cluster with at least two pollen cones showing longitudinal section of possible bract (br) subtending a pollen cone (MPEF-Pb2429). C, Specimen showing cluster of four pollen cones; note that morphology and disposition of leaves on the branch are the same as nonfertile shoots (MPEF-Pb2933). D, Close-up of H showing persistent pollen cone (pc) and subtending ovate bracts (br). Note thickening of shoot axis, incomplete preservation of bracts on the right side, and possible basal part of a pollen cone axis (pc?; MPEF-Pb6762). E, Surface view of dispersed pollen cone showing ovate shape of distal laminas of microsporophylls (MPEF-Pb2508). F, Dispersed pollen cone in longitudinal section (MPEF-Pb2502a). G, Dispersed pollen cone (MPEF-Pb6767). H, Penultimate shoot with laterally attached pollen cone and subtending bracts. Note regular leaves and shoot elongation distal to the pollen cone and bracts (MPEF-Pb6762). I, Detail of lower two microsporophylls (ms) from pollen cone in G viewed under epifluorescence, showing attached pollen sacs (ps; MPEFPb6767). J, Microsporophyll viewed under epiflourescence, showing microsporophyll stalk (st) oriented perpendicular to the axis, upturned distal lamina (ms), and pollen sac (ps; MPEF-Pb2952). K, Illustration of microsporophylls and pollen sacs in I. Scale bars p 1 cm (A-C, H), 5 mm (D), 2 mm (E-G), 0.5 mm (I, F).
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Compression/impressions of seed cones of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov. A-C, Seed cones showing attachment to penultimate and ultimate shoots. D-I, Closed cones. J, Open cone. A, Two seed cones attached to shoot system. Note densely arranged, shorter leaves below cone (arrow; MPEF-Pb2452). B, Terminal, single seed cone attached to shoot (MPEF-Pb2904b). C, Two cones attached to shoot system (MPEF-Pb1794a). D, Impression of surface of closed ovuliferous cone showing acute apex of cone with protruding acuminate apexes (a) of the terminal ovuliferous complexes. Note that the apexes of most complexes are not completely visible because of their curvature away from the surface of the cone (MPEF-Pb1616). E, Seed cone showing external surface morphology, the shape of ovuliferous complexes, and small leaves that transition to the base of the cone (MPEF-Pb2967). F, Surface of seed cone showing thick, prominent keels on ovuliferous complexes (MPEF-Pb2444). G, Detail of F showing rugose texture of the thick abaxial keel (k; MPEF-Pb2444). H, Cone surface showing thick keels (MPEF-Pb3877). I, Cone split longitudinally, showing internal structure of cone. The adaxial surface of ovuliferous complexes (ad) and one complex showing the abaxial surface with keel (k) are visible. Note the decurrent base of the ovuliferous complexes on the cone axis (arrow), the presence of the keel on the entire length of the complex, and the outwardly pointed apexes (a; MPEF-Pb2457). J, Open cone showing general morphology of ovuliferous complexes. Note that the apex of the cone is incomplete (holotype; MPEF-Pb2463a). Scale bars p 1 cm (A-E, H-J), 5 mm (F), 2 mm (G).
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SPECIAL ISSUEROTHWELL CELEBRATION
RECONSTRUCTING THE EARLY EVOLUTION OF THE CUPRESSACEAE: A WHOLE-PLANT
DESCRIPTION OF A NEW AUSTROHAMIA SPECIES FROM THE CAÑADÓN
ASFALTO FORMATION (EARLY JURASSIC), ARGENTINA
Dori L. Contreras,
1,
* Ignacio H. Escapa,Rocio C. Iribarren,and N. Rubén Cúneo
*University of California Museum of Paleontology, 1101 Valley Life Sciences Building, Berkeley, California 94720, USA; Museo Paleontológico
Egidio Feruglio, Avenida Fontana 140, Trelew, 9100 Chubut Province, Argentina; and Instituto de Botánica Darwinion
CONICETANCEFN, Labardén 200, Casilla de Correo 22, B1642HYD San Isidro, Buenos Aires, Argentina
Guest Editor: Alexandru M.F. Tomescu
Premise of research. A new Early Jurassic species of Cupressaceae is reconstructed from the Cañadón
Asfalto Formation in Argentina, based on impressions of foliage and attached and dispersed seed and pollen
cones.
Methodology. Over 230 specimens were examined using reected-light microscopy and epiuorescence.
Relevant extant taxa were studied for structural comparisons using herbarium specimens and living material
from botanical gardens. Relationships of the new conifer were assessed in the context of currently known fos-
sil and living taxa and used to evaluate morphological trends in the early evolution of Cupressaceae.
Pivotal results. The new species, Austrohamia asfaltensis D.L. Contreras, I.H. Escapa, R.C. Iribarren, &
N.R. Cúneo, has helically arranged, dorsiventrally attened leaves that are rotated into semiplanar orienta-
tion, seed cones consisting of helically arranged coriaceous ovuliferous complexes that each bear two seeds
and have a distinct abaxial keel and acuminate apex, and pollen cones that occur in clusters subtended by
keeled bracts. Specimens show evidence that normal vegetative shoot growth continues from the pollen cone
clusters, a condition that appears to characterize living Cunninghamia and some extinct conifers but not
Taiwania. The new species is assignable to the genus Austrohamia, which shares a combination of char-
acteristics consistent with the Cunninhamioideae and Taiwanioideae subfamilies of the Cupressaceae. It is dis-
tinct from other Austrohamia species, most notably by having seed cones that are twice as large and with
many more ovuliferous complexes.
Conclusions. The new species expands the known morphological diversity of Austrohamia, which is the
oldest recorded genus of Cupressaceae based on reproductive material, and provides a new early occurrence of
the family in the Southern Hemisphere. The development of a whole-plant concept enabled morphological
comparisons over a broad range of traits and with taxa known from different combinations of organs, which
has provided additional insights into the early evolution of Cupressaceae.
Keywords: Austrohamia, conifer, Cupressaceae, Early Jurassic, Patagonia, whole-plant reconstruction.
Introduction
The Cupressaceae sensu lato (cypress family) is one of the
most diverse and geographically widespread conifer families,
occupying a range of habitats from arid environments to wet
forests worldwide (Hill and Brodribb 1999; Farjon 2005;
Eckenwalder 2009; Pittermann et al. 2012). Accordingly, the
physiological and morphological disparity within the family is
remarkable (Eckenwalder 1976; Pittermann et al. 2012), with
representatives of some of the largest and oldest trees on Earth
(e.g., Sequoia Endlicher, Sequoiadendron Buchholz, Taxodium
mucronatum Ten., Fitzroya Hook. f. ex Lindl., Taiwania Ha-
yata, Chamaecyparis Spach) and some of the smallest conifers
alive (e.g., Microbiota Komarov). The living Cupressaceae
sensu lato (hereafter, simply Cupressaceae)consistsof32gen-
era distributed throughout both hemispheres, many of which
provide substantial ecosystem services and are of considerable
economic importance (Farjon 2005, 2010; Eckenwalder 2009).
The Cupressaceae has been repeatedly supported as the sis-
ter group of the Taxaceae sensu lato (including former Cepha-
lotaxaceae); together with Sciadopitys Siebold et Zucc., it
forms the order Cupressales (Christenhusz et al. 2011), which
is sister to the Araucariales (Rai et al. 2008; Leslie et al. 2012;
Mao et al. 2012; Forest et al. 2018). The Cupressaceae is no-
table for including an extant grade of early-diverging lineages,
composed of the former Taxodiaceae (now often referred to
1
Author for correspondence; email: dorilynne@berkeley.edu,
dorilynnecontreras@gmail.com.
Manuscript received February 2019; revised manuscript received May 2019;
electronically published September 4, 2019.
Int. J. Plant Sci. 180(8):834868. 2019.
q2019 by The University of Chicago. All rights reserved.
1058-5893/2019/18008-0004$15.00 DOI: 10.1086/704831
834
as the taxodiaceous Cupressaceae; Eckenwalder 1976; Hart
1987; Price and Lowenstein 1989; Brunsfeld et al. 1994; Gadek
et al. 2000; Kusumi et al. 2000). Molecular phylogenetic anal-
yses have delineated seven major lineages (subfamilies) within
the Cupressaceae (Gadek et al. 2000; Kusumi et al. 2000;
Schulz and Stützel 2007; Leslie et al. 2012; Mao et al. 2012;
Shi et al. 2014). The taxodiaceous grade comprises ve of these
subfamilies, but it is represented by only nine extant genera
with a disjunct geographical distribution and a total of 13 ex-
tant species (Gadek et al. 2000; Farjon 2005; Mao et al. 2012).
The taxodiaceous Cupressaceae has an extensive fossil rec-
ord that indicates that the modern representatives are relicts
of once far more diverse and widespread groups of conifers
(see Stockey et al. 2005; Herrera et al. 2017). They were com-
mon in, and often dominant components of, late Mesozoic
and early Cenozoic ecosystems worldwide (e.g., Srinivasan
and Friis 1989; Hill and Brodribb 1999; Stockey et al. 2005;
Kunzmann et al. 2009; Lepage 2009; Taylor et al. 2009;
Atkinson et al. 2014a, 2014b; Klymiuk et al. 2015; Escapa
et al. 2016; Rothwell and Ohana 2016; Herrera et al. 2017;
Sokolova et al. 2017; Dong et al. 2018). The oldest whole-plant
reconstruction including both reproductive and vegetative
organs, and unequivocal record of Cupressaceae, is Austro-
hamia minuta Escapa, Cúneo, et Axsmith, from the Early Juras-
sic of Patagonia, Argentina (Escapa et al. 2008a; Bodnar and
Escapa 2016). However, isolated organs with suggested cu-
pressaceous afnities have been reported from the Triassic
(e.g., leaves from France [Lemoigne 1967] and wood from
Argentina and China [Bodnar and Artabe 2007; Bodnar et al.
2015; Wan et al. 2017]). By the Middle-Late Jurassic, cupressa-
ceous conifers were particularly abundant in the Northern
Hemisphere (g. 1), coinciding with the distribution of warm
temperate to tropical paleoclimates (see Rees et al. 2000; Ziegler
et al. 2003; Golonka 2007). Representatives of the taxodiaceous
Cupressaceae continued to become increasingly diverse and
common throughout the Cretaceous (Stockey et al. 2005 and
references therein; Escapa et al. 2008a, 2016; Lepage 2009;
Zhang et al. 2012; Atkinson et al. 2014a, 2014b; Dong et al.
2014; Herrera et al. 2017). The relictual distribution and mod-
ern biogeographic pattern of extant taxodiaceous Cupressaceae
have thus been interpreted as the result of successive extinctions
and shifts to more arid environments during the Cenozoic, with
older lineages persisting in wet environments (Crisp and Cook
2011; Leslie et al. 2012; Mao et al. 2012; Pittermann et al.
2012).
The inclusion of some of the more completely known fossil
taxa in phylogenetic analyses has recently advanced our gen-
eral understanding of the relationships between extinct and
living representatives of early-divergent Cupressaceae lineages
(Escapa et al. 2008a; Rothwell et al. 2011; Shi et al. 2014;
Herrera et al. 2017; Dong et al. 2018). Although the relative
placement of taxa is not unambiguously resolved, such studies
have consistently recognized an expanded cunninghamioid
clade that includes living and fossil Cunninghamia Brown
ex Richard and similar fossil taxa such as Sewardiodendron
Florin, Elatides Heer spp., Cunninghamiostrobus Stopes et
Fujii spp., Hubbardiostrobus Atkinson, Rothwell et Stockey,
Hughmillerites Rothwell, Stockey, Mapes et Hilton, and
Pentakonos Herrera, Shi, Knopf, Leslie, Ichinnorov, Takaha-
shi, Crane et Herendeen (Harris 1943, 1953; Yao et al. 1998;
Escapa et al. 2008a; Rothwell et al. 2011; Atkinson et al.
2014a, 2014b; Shi et al. 2014; Herrera et al. 2017). Some
of these studies also support the inclusion of Taiwania and
Austrohamia Escapa, Cúneo et Axsmith in the expanded
clade (hereafter, cunninghamioid-taiwanioid complex; Farjon
et al. 2002, 2005; Escapa et al. 2008a; Dong et al. 2018).
Fig. 1 Distribution of Jurassic Cupressaceae. Geographic locations of known fossil Cupressaceae representatives plotted from the Paleobi-
ology Database (http://paleodb.org), with additional occurrences of important taxa not in the database added manually. All occurrences are plot-
ted on a paleogeographic reconstruction for the Early/Middle Jurassic (~175 Ma; Wright et al. 2013).
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 835
Understanding the diversity and relationships of the early-
divergent lineages of extant families is important for recon-
structing the broader evolutionary dynamics of conifers. The
large morphological distances between extant families make
it difcult to assess relationships of, and homologies among,
distinct fossil groups and the modern families (Spencer et al.
2015; Escapa and Leslie 2017; Leslie et al. 2018). A thorough
understanding of the characteristics of the earliest-diverging
taxa of well-known clades is needed in order to use basal
character optimizations to recognize sister taxa among fossil
conifers and close the morphological gaps between extant
lineages, and to enable reconstruction of their relationships
with the voltzian Voltziales and other transitional conifers
(Miller 1999; Serbet et al. 2010; Rothwell et al. 2011; Herrera
et al. 2015; Spencer et al. 2015).
Here, we describe a new Early Jurassic cupressaceous coni-
fer from Patagonia, Argentina, based on multiple organs and
assign it to Austrohamia. We then evaluate its relationships
with other fossil and living taxa within the context of within-
and between-organ variability. Finally, these comparisons are
used to assess characters common to cunninghamioid and
tawanioid taxa and provide a summary of the evolution of
early Cupressaceae.
Material and Methods
Geologic Setting and Age
The Somuncurá-Cañadón Asfalto Basin represents the most
extensive exposures of Jurassic terrestrial continental rocks in
southern South America (Cúneo et al. 2013; Figari et al.
2015). Rocks of the southern Cañadón Asfalto Basin are ex-
posed in outcrops within the Chubut River valley located in
the central Patagonian Chubut Province of Argentina (Cúneo
et al. 2013). The basin is interpreted as a continental rift basin
with several sedimentary depocenters, recording uvial, lacus-
trine, and volcanic deposition (Figari et al. 2015). Sediments
of the Cañadón Asfalto Basin have been grouped into three
megasequences based on the evolutionary phases of the basin
(see Figari et al. 2015). The rst sequence, representing the
formation of the depocenters during the Early to Middle Ju-
rassic, is composed of the Las Leoneras Formation, the Lonco
Trapial Formation, and the Cañadón Asfalto Formation. The
last is unconformably overlain by the Cañadón Calcáreo For-
mation of the second megasequence. The fossils described
here were collected from the Sitio Frenguelli locality within
the lower strata of the Cañadón Asfalto Formation in the Cerro
Cóndor area (Escapa et al. 2008b; Cúneo et al. 2013).The fossils
come from a ~20-cm-thick layer of black lacustrine sediments
that are ne grained and have parallel lamination. Although
the Cañadón Asfalto Formation was traditionally interpreted
as Middle to Upper Jurassic based on fossil freshwater inver-
tebrates and plants (e.g., Frenguelli 1949), more recent U-Pb
geochronology on tuff beds throughout the basin indicates a
mid-late Toarcian to Aalenian (Bajocian?) age (Early to Middle
Jurassic; Cúneo et al. 2013). Specically, the Sitio Frenguelli
site occurs 10 m below a tuff dated to 178.77 50.09 Ma
(Cúneo et al. 2013), thus rmly placing these specimens in
the Early Jurassic (ca. 179 Ma).
Paleontological Background
The fossil ora at Sitio Frenguelli is largely dominated by co-
nifer leaves, seed and pollen cones, including the taxon de-
scribed here, and two other undescribed taxa that belong to
the families Araucariaceae and Cheirolepidiaceae. The oral
spectrum is completed by less frequent fern pinnules and equi-
setalean fragments (Escapa 2009).
Frenguelli (1949) described two species of Palissya Endlicher
emend. Florin based on a few specimens from Sitio Frenguelli or
a nearby locality in the Cañadón Asfalto Formation. The sepa-
ration into two taxa was due primarily to size differences that
probably resulted from the incompleteness of the collection.
The assignment of the specimens to the genus Palissya was
based on the interpretation that each ovuliferous complex
possesses four or ve ovules in one or two linear series from
the base to the distal portion of the complex. Investigations of
the same materials and additionally collected specimens do
not conrm that observation (see Escapa et al. 2008b). Based
on newer collections from Sitio Frenguelli, Escapa (2009) de-
scribed conifer specimens that were preliminarily assigned to
the genus Elatides. These specimens have been reinterpreted
here in the context of even larger collections from the locality.
Fossil Preparation and Illustration
More than 55 vegetative and 179 reproductive specimens
were collected over multiple trips during eld seasons between
2003 and 2013 and deposited at the Museo Paleontológico
Egidio Feruglio Paleobotanical Collection in Trelew, Argentina
(hereafter, MPEF-Pb). Standard techniques for compression/
impressions were used for preparation and study of the speci-
mens described herein. Fossils were viewed using a Zeiss
(Oberkochen, Germany) MC80DX stereoscope with a camera
lucida attached and photographed using a Canon (Tokyo, Ja-
pan) Mark 7D digital camera with a 60-mm lens. Further
magnications were obtained using extension tubes attached
to the lens.
Specimens were also viewed under epiuorescence and photo-
graphed using an attached Nikon (Tokyo, Japan) digital camera.
For most specimens, this did not enable visualization of addi-
tional details. In a few cases, however, fragmentary pieces of
cuticle, imprints of epidermal cells, and pollen sacs were ob-
served. To generate clear, fully focused images, each eld of view
was photographed at multiple planes of focus, then the images
were stacked using the auto-align and auto-blend functions in
Adobe Photoshop (San Jose, CA). In some cases (gs. 5A,5E,
6I,6J,8C,8E), a composite image was created using both im-
age stacking and image stitching in order to visualize the entire
specimen.
Extant Comparisons
Living Cupressaceae specimens at the University of Califor-
nia Botanical Garden at Berkeley were studied for comparisons
of structure and habit. Pollen cones were collected from January
to April during 2013, 2014, and 2015, xed in the eld with
FAA, and transferred to 70% EtOH after 24 h. Dissections
were made on a Leica (Wetzlar, Germany) EZ4 HD stereo-
scope and photographed with the integrated camera. Image
stacking was performed in Photoshop as described above. Larger
836 INTERNATIONAL JOURNAL OF PLANT SCIENCES
specimens were photographed with a Canon EOS 5D Mark III
camera with a 100-mm lens.
Terminology
In this article, we use the term ovuliferous complexto refer
to the lateral ovule-bearing unit of the ovuliferous cone rather
than the term bract-scale complex(see discussion of these
terms in Escapa et al. 2008a, 2016). In many Cupressaceae,
there is no physical or developmental distinction that allows
recognition of a separate bract and ovuliferous scale (e.g.,
Tomlinson and Takaso 2002), and it is therefore generally as-
sumed that the ovuliferous scale has been fully reduced in these
taxa (Rothwell et al. 2011).
Distribution and Paleomaps
Distribution maps of fossil basal Cupressaceae taxa were
generated using the Paleobiology Database (PBDB; http://
paleodb.org). Search parameters were limited to the Jurassic,
with separate searches run for Cupressaceaeand for each
known or proposed cupressaceous genus. All occurrences were
plotted using a paleogeographic reconstruction date of 175 Ma
(Wright et al. 2013). The data set was supplemented with bio-
geographically important occurrences that were not in PBDB,
consisting of Austrohamia,Sewardiodendron,Hughmillerites,
Acanthostrobus Klymiuk, Stockey et Rothwell, and Scitistro-
bus Spencer, Mapes, Hilton et Rothwell (Yao et al. 1998;
Escapa et al. 2008a; Rothwell et al. 2011; Zhang et al. 2012;
Klymiuk et al. 2015; Spencer et al. 2015). Results were com-
piled on the same map using Adobe Illustrator (San Jose, CA).
Results
Systematics
OrderConiferales sensu Eckenwalder
FamilyCupressaceae sensu lato Bartling
GenusAustrohamia Escapa, Cúneo et Axsmith,
Here Emended
Emended generic diagnosis. Leafy shoots with at least two
orders of branching; ultimate branchlets alternate or subop-
posite with helically arranged leaves. Leaves decurrent at base
with distal rounded tip, attened dorsiventrally and univeined.
Ovuliferous cones elliptical, borne terminally on ultimate and
penultimate branches, composed of helically arranged ovu-
liferous complexes with ovules disposed on their adaxial sur-
faces. Individual pollen cones axillary and aggregated in
clusters that are borne at the end of leafy shoots; each pollen
cone composed of helically arranged microsporophylls with ab-
axial pollen sacs.
SpeciesAustrohamia asfaltensis D.L. Contreras,
I.H. Escapa, R.C. Iribarren, & N.R. Cúneo,
sp. nov. (Figs. 38)
Specic diagnosis. Branching alternate to subopposite.
Leaves helically arranged, decurrent, with single midvein, en-
tire margins, apexes mostly rounded. Free portion of blade
lanceolate to oblong or slightly tapering, departing from
shoot at angles up to 907, curving or twisting at base to orient
blades in roughly one plane. Epidermal cells rectangular, elon-
gate, in longitudinal les, with straight walls. Stomata in two
bands on either side of the midvein. Pollen cones arranged in
clusters, with up to ve cones. Each pollen cone borne in axil
of broadly ovate bract with acute apex. Pollen cones ovate to
elliptic in shape, consisting of a central axis surrounded by
helically arranged, imbricate microsporophylls. Microsporo-
phylls consist of a narrow stalk broadening to an upturned,
ovate distal lamina. Pollen sacs elongate-elliptic, attached at
the base of the distal lamina, and oriented parallel to the mi-
crosporophyll stalk. Seed cones terminal on penultimate or ul-
timate shoots, greater than 1.5 cm long at maturity, with he-
lically arranged, imbricate ovuliferous complexes. Ovuliferous
complexes do not show a morphological distinction between
bract and ovuliferous scale. Each ovuliferous complex coria-
ceous and bifacially attened, with a narrow stalk and a
broadly ovate distal face, an acuminate apex, and a promi-
nent abaxial keel extending from the base to the tip of each
bract. Each ovuliferous complex bears two inverted ovules/
seeds on the adaxial surface, positioned medially to slightly dis-
tally on the complex. Ovules/seeds elliptic, narrowed slightly to-
ward the micropylar end.
Holotype. Specimen Pb2463a,b, housed in the Museo
Paleontológico Egidio Feruglio Paleobotanical Collection in
Trelew, Argentina (MPEF-Pb; g. 6J).
Paratypes. Specimens Pb2134a,b,c; Pb6763; Pb1821;
Pb6767; Pb2430a,b; Pb2429; Pb2933; Pb6762; Pb2452;
Pb2904; Pb1794; Pb1616; Pb2967; Pb2457; Pb2444;
Pb2469/1619a,b; Pb2958; Pb2496; Pb2484; Pb2901 (MPEF-
Pb; gs. 3A,3C,3D,4A4D,5D5F,6A6D,6G6I,7A
7E,7I,7F,7G,8A8H).
Type locality. Sitio Frenguelli (GPS coordinates upon
request).
Stratigraphy and age. Cañadón Asfalto Formation in the
Cañadón Asfalto Basin; Early Jurassic, ~179 Ma.
Etymology. The specic epithet refers to the Cañadón
Asfalto Formation, which yields the plant fossils.
Additional material. Specimens Pb1614, Pb1615, Pb1617,
Pb1618, Pb1620, Pb1621, Pb1622, Pb1623, Pb1624, Pb1625,
Pb1626, Pb1627, Pb1628, Pb1629, Pb1630, Pb1631, Pb1632,
Pb1633, Pb1654, Pb1658, Pb1661, Pb1669, Pb1674, Pb1797,
Pb1798, Pb1799, Pb1800, Pb1801, Pb1804, Pb1805, Pb1807,
Pb1809, Pb1810, Pb1811, Pb1812, Pb1813, Pb1815, Pb1816,
Pb1817, Pb1819, Pb1822, Pb1823, Pb1824, Pb1825, Pb1827,
Pb1828, Pb1829, Pb1830, Pb1831, Pb1832, Pb1833, Pb1834,
Pb1835, Pb1836, Pb1839, Pb1841, Pb1842, Pb2003, Pb2004,
Pb2014, Pb2019, Pb2128, Pb2130, Pb2131, Pb2132, Pb2133,
Pb2139, Pb2429, Pb2431, Pb2432, Pb2433, Pb2434, Pb2435,
Pb2436, Pb2437, Pb2438, Pb2439, Pb2440, Pb2441, Pb2442,
Pb2443, Pb2445, Pb2446, Pb2447, Pb2448, Pb2449, Pb2450,
Pb2451, Pb2453, Pb2454, Pb2455, Pb2456, Pb2458, Pb2459,
Pb2460, Pb2461, Pb2462, Pb2464, Pb2465, Pb2466, Pb2467,
Pb2468, Pb2470, Pb2471, Pb2472, Pb2473, Pb2474, Pb2475,
Pb2476, Pb2477, Pb2478, Pb2479, Pb2480, Pb2481, Pb2482,
Pb2483, Pb2485, Pb2486, Pb2487, Pb2488, Pb2489, Pb2490,
Pb2491, Pb2492, Pb2493, Pb2494, Pb2495, Pb2497, Pb2499,
Pb2500, Pb2501, Pb2502, Pb2506, Pb2508, Pb2903, Pb2911,
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 837
Pb2912, Pb2915, Pb2916, Pb2918, Pb2920, Pb2921, Pb2922,
Pb2923, Pb2924, Pb2925, Pb2926, Pb2927, Pb2928, Pb2930,
Pb2931, Pb2932, Pb2934, Pb2935, Pb2936, Pb2937, Pb2938,
Pb2939, Pb2940, Pb2941, Pb2942, Pb2945, Pb2946, Pb2952,
Pb2953, Pb2954, Pb2955, Pb2959, Pb2961, Pb2962, Pb2963,
Pb2964, Pb2965, Pb2966, Pb2968, Pb2969, Pb2970, Pb2972,
Pb3877, (MPEF-Pb).
Detailed Description
Vegetative axes. Vegetative specimens consist of one or
two orders of branching, representing the ultimate and penul-
timate shoots (g. 2). The axes of penultimate shoots are up
to 4.5 mm wide (average, 2 mm), and ultimate shoots range
from 1.1 to 1.6 mm wide. Both axes are densely covered by
the imbricate, decurrent leaf bases of helically arranged, dor-
siventrally attened leaves (gs. 2, 3). The lateral ultimate
shoots are borne predominantly alternate (g. 2A,2C) but oc-
casionally subopposite with up to 4 mm between shoots of the
same pair (g. 2B), and they appear to be disposed about the
penultimate axis in one plane (g. 2A2C). Spacing between
successive ultimate shoots is on average 12 mm. Ultimate
shoots are attached in the axils of normal foliar leaves and di-
verge at angles between 507and 607(up to 807) to the main
axis (gs. 2A2C,3A). Bud scales or highly reduced leaves in-
dicative of a dormant resting phase are not found at the bases
of ultimate shoots, although leaves in the basal portion of
shoots may be reduced in size (g. 2C,2F). In cases where
the basalmost portion of a multiple-order shoot system ap-
pears to be completely preserved, the base of the highest-order
axis is thickened, suggesting active abscission of the entire fo-
liage splay (cladoptosis; g. 2A, arrow). Shoots are generally
preserved as carbonaceous compressions, and in cases where
whole leaves are not present, it is common to observe im-
pressions or remnants of the decurrent leaf bases along the
shoot (g. 2B,2F). Leaves are rarely found individually dis-
persed in the matrix, except when found with shoots that ap-
pear to have been degrading or disturbed prior to fossilization
(gs. 2B,5H). Therefore, they are interpreted to be persistent
on the shoot axes.
Leaves are decurrent along the stem, with the visible
adpressed portion usually less than 3 mm long (longest on
penultimate shoots) and the free blade ranging from 3.8 to
10 mm long (g. 3A,3B,3D). The adpressed bases trend par-
allel to slightly oblique to the axis and overlap with subsequent
leaf bases (g. 3B,3D,3E). The degree of overlap varies de-
pending on shoot position, with leaves toward the apex being
more imbricate and forming a tuftof leaves surrounding
the apical meristem (g. 3C). Leaves are dorsiventrally at-
tened, the shape of the free part oblong to slightly tapering to-
ward the tip, and occasionally somewhat lanceolate, with entire
margins and obtuse to broadly acute apexes with bluntly
rounded or pointed tips (g. 3A,3B). The width of leaf blades
ranges from 0.8 to 1.8 mm, with the maximum width of leaves
1.8 mm on penultimate shoots and 1.5 mm on ultimate shoots.
Length-to-width (LW) ratios vary on the same shoot de-
pending on relative position, with basal leaves having lower
LWratios(gs. 2A,2C,3A). The free parts of the leaves di-
verge from the shoot axis at angles commonly up to 907(g.
3A3E) and lack a constriction or narrowing at the point of de-
parture (g. 3D). On ultimate shoots, it is common for leaf
blades to curve or twist near their point of departure from
the shoot axis so that the adaxial leaf surfaces are oriented in
one direction, resulting in a semiplanar disposition of leaf
blades on the shoot (g. 3B,3D). Leaves borne on the abaxial
side of branches curve outward, while those borne on the ad-
axial side of branches twist at the point of departure from
the stem (g. 3B,3D). In the basal- and apical-most regions,
as well as on penultimate shoots, leaves sometimes retain their
helical disposition of leaf blades (gs. 2C,2E,3A,3C,3E).
Each leaf has one simple, medial vein, which is on average
0.8 mm thick and largely maintains its width for 190% of
the length of the leaf until losing gauge right before reaching
the blunt apex (g. 3A).
Most specimens have preserved organic remains, which are
carbonaceous and nely fragmented. Only a few have re-
maining fragments of cuticles, which are too poorly preserved
to discern any diagnostic characteristics. However, in some
cases, two darkened parallel lines, which are carbonaceous
and likely represent stomatal bands, are visible on either side
of the midvein (g. 4B,4D). Furthermore, in several speci-
mens, imprints of epidermal cells can be seen on the surface
of the matrix where the carbonaceous material is removed
(g. 4A,4C,4F,4G). These represent the outer surface of
the epidermis. Normal epidermal cells are organized in longi-
tudinal les and are roughly rectangular in outline: 45.0
90.4 mm (average, 65.6 mm) long by 12.617.8 mm (average,
15.2 mm) wide, with a LW ratio of 4.31. They are elon-
gated parallel to the midvein and have straight anticlinal walls
(g. 4A,4C4F). In several cases, areas where the orientation
of epidermal cells is disrupted can be seen on either side of the
midvein (g. 4C,4E), and these correspond to the dark lines
interpreted as stomatal bands (g. 4E,4F). If these disruptions
indeed represent stomata, this suggests that they were oriented
irregularly rather than parallel to the midvein. On one isolated
leaf specimen with impressions representing the adaxial leaf
surface, these stomatal disruptionsare visible only at the base
of the leaf (g. 4A,4C), suggesting, but not conclusively, that
while stomata occur on both leaf surfaces, the leaves are primar-
ily hypostomatic. Stomatal morphology has not been found
well preserved.
Pollen cones. Pollen cones are underrepresented in the sam-
ple compared with ovuliferous cones, with only four specimens
showing organic attachment of pollen cones to shoots (g. 5A
5D,5H). In three of these specimens, the pollen cones are lo-
cated at the end of shoots in groups of at least two to ve cones
densely aggregated into a cluster (g. 5A5C). Based on their
size and relative compactness compared with associated dis-
persed pollen cones, we interpret these as immature cones (be-
fore pollen dispersal). Unfortunately, the details of their attach-
ment to the shoot or of the subtending leaves are not well
preserved in these three specimens (g. 5A5C). However, the
remnants of a mature pollen cone, consisting of the axis bearing
a few microsporophylls, are found attached laterally to a penul-
timate shoot between increments of normal vegetative growth
(g. 5D,5H). The shoot is abruptly thickened at the point of
pollen cone attachment (g. 5H), with two modied leaves
(bracts) also visible, one of which subtends the axillary pollen
cone (g. 5D). The bracts are broadly ovate, approximately
3.5 mm long and 2 mm wide, and bluntly keeled abaxially
838 INTERNATIONAL JOURNAL OF PLANT SCIENCES
Fig. 2 Foliage impressions of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov. AC, Penultimate and ultimate
shoots showing branching habit; DF, Isolated shoots. A, Foliated shoot with two orders of branching showing alternate branching in one plane.
Note swollen base of penultimate shoot (arrow; MPEF-Pb2134a,b,c). B, Foliated shoot with two orders of branching showing alternate and
subopposite (arrows) branching (MPEF-Pb2499). C, Foliated shoot with two orders of branching showing alternate arrangement of branches
oriented in one plane (MPEF-Pb6763). D, Ultimate shoot showing leaf size variability along shoot and apical tuft of leaves (arrow; MPEF-
Pb1821). E, Shoot showing reduced leaves at base that are helically disposed, transitioning to larger leaves that are curved or twisted to orient
blades in one direction (MPEF-Pb1831). F, Shoot showing near-distichous arrangement of leaf blades along a portion of the shoot (MPEF-
Pb2941). Scale bars p1 cm.
(g. 5D). Distal to the pollen cone and bracts, the shoot
continues vegetative growth (g. 5D,5H). The specimen is in-
completely preserved, and although only one pollen cone is vis-
ible, the thickened shoot and presence of multiple bracts suggest
that multiple aggregated pollen cones were attached. Pollen
cones are thus borne at the end of a shoot in the axils of modi-
ed leaves (bracts) and are densely aggregated to form a cluster.
They do not terminate the apex of the shoot, which presumably
resumes normal vegetative growth after pollen release, leaving
the bracts and pollen cones persistent on the axis. Leaves on
the branches bearing the pollen cone clusters are the same as
those on the vegetative axes, although slightly reduced in size
right below the cluster (g. 5A5C,5H).
Detached pollen cones are also found (g. 5E5G), con-
sisting only of a central axis surrounded by helically arranged
microsporophylls. Dispersed pollen cones are usually found
isolated, suggesting that the cones are either abscised individ-
ually or persistent with the thin pollen cone axis eventually
breaking (the latter is most consistent with the specimen show-
ing lateral attachment to a penultimate shoot). Individual pol-
len cones are ovate to elliptic (g. 5E5G); immature cones (be-
fore dispersal) are 3.97.8 mm long and 2.63.4 mm wide, and
Fig. 3 Morphological details of leaf impressions of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov. AD, Close-up
of leaves from gure 2A,2C,2D.A, Detail of leaves on penultimate and ultimate axes from gure 2Ashowing general morphology of leaves and
size variation within and among shoots. Note decurrent leaf bases (arrows), distinct midvein (m), and bluntly rounded apexes (a; MPEF-
Pb2134a). B, Detail of leaves showing twisting (tw) of base of the free leaf blade to orient the adaxial leaf surface upward and imbricate decur-
rent leaf bases that trend mostly parallel to the shoot axis (MPEF-Pb1821). C, Detail of the end of an isolated shoot showing small tuft of leaves
covering the apical meristem (MPEF-Pb1821). D, Detail of impression of underside of ultimate shoot from gure 2Cshowing leaves curving (cu)
to orient the abaxial surface leaf blades in one plane (MPEF-Pb6763). Note some leaf bases trending oblique to the shoot axis. E, Isolated shoot
showing high angle of departure, lax appearance of leaves, and leaf blades oriented to give the appearance of a vertically oriented shoot (MPEF-
Pb1805). Scale bars p5 mm.
840 INTERNATIONAL JOURNAL OF PLANT SCIENCES
dispersed cones are 7.99.3 mm long and 3.14.1 mm wide.
The axis of each cone is up to 0.57 mm wide basally and be-
comes more narrow toward the apex. Numerous microsporo-
phylls (up to 26 counted in partial face view, estimated 130
501) are helically disposed around the axis (g. 5E). The thin
stalk-like portion of each microsporophyll (0.110.13 mm wide,
up to 1.0 mm long) is oriented approximately perpendicular to
the central axis and turns upward abruptly as it expands in
widthtoformaattened distal lamina oriented perpendicular
to the stalk (g. 5F). The abaxial external face of each micro-
sporophyll is ovate to rhomboidal in outline, up to 1.6 mm long
and 1.1 mm wide, with an acute apex (g. 5E). Microsporo-
phylls are slightly imbricate, with the apex overlapping the sub-
sequent microsporophyll distal lamina (g. 5E5G). They have
an entire margin and a smooth abaxial face (i.e., no keel;
g. 5E). Pollen sacs were observed in longitudinal section on
Fig. 4 Anatomical details of compression/impression leaves of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov.
A,C,EG, Epidermal details of leaves from cellular imprints viewed through a compound scope with epiuorescence. B,D, Leaves showing dark-
ened lateral bands (b) likely representing stomatal regions. White brackets indicate regions enlarged in a separate panel indicated with the white letter.
A, Isolated leaf showing general pattern of epidermal cells (MPEF-Pb6762). B, Leaves showing two dark bands (b) of carbonized remains, one on
each side of midvein, representing stomatal regions (MPEF-Pb1831). C, Close-up of lower part of leaf from Ashowing longitudinal les of epidermal
cells disrupted by a region of cells with irregular orientation, representing stomata (st; MPEF-Pb6762). D, Isolated leaf showing two lateral dark
bands, representing stomatal regions (MPEF-Pb6767). E, Close-up of leaf from Dshowing pattern of epidermal cells along medial region of leaf
(MPEF-Pb6767). F, Close-up of region of leaf from Eshowing the carbonized lateral band (b) and underlying imprints of irregularly oriented
cells, likely representing the stomata (st). Note that the epidermal cells on either side of the carbonized band are longitudinal les (MPEF-
Pb6767). G, Detail of normal epidermal cells, rectangular in shape with straight end walls (MPEF-Pb6762). Scale bars p1mm(A,D), 5 mm (B),
0.5 mm (C,E), 0.25 mm (F,G).
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 841
Fig. 5 Pollen cones of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov. AC, Clusters of immature pollen cones at
ends of foliage shoots. EG, Dispersed pollen cones. I,J, Microsporophylls viewed through a compound microscope with epiuorescence.
A, Cluster with at least ve pollen cones (MPEF-Pb2430b). B, Cluster with at least two pollen cones showing longitudinal section of possible
bract (br) subtending a pollen cone (MPEF-Pb2429). C, Specimen showing cluster of four pollen cones; note that morphology and disposition of
leaves on the branch are the same as nonfertile shoots (MPEF-Pb2933). D, Close-up of Hshowing persistent pollen cone (pc) and subtending
ovate bracts (br). Note thickening of shoot axis, incomplete preservation of bracts on the right side, and possible basal part of a pollen cone axis
(pc?; MPEF-Pb6762). E, Surface view of dispersed pollen cone showing ovate shape of distal laminas of microsporophylls (MPEF-Pb2508).
F, Dispersed pollen cone in longitudinal section (MPEF-Pb2502a). G, Dispersed pollen cone (MPEF-Pb6767). H, Penultimate shoot with laterally
attached pollen cone and subtending bracts. Note regular leaves and shoot elongation distal to the pollen cone and bracts (MPEF-Pb6762).
I, Detail of lower two microsporophylls (ms) from pollen cone in Gviewed under epiuorescence, showing attached pollen sacs (ps; MPEF-
Pb6767). J, Microsporophyll viewed under epiourescence, showing microsporophyll stalk (st) oriented perpendicular to the axis, upturned distal
lamina (ms), and pollen sac (ps; MPEF-Pb2952). K, Illustration of microsporophylls and pollen sacs in I. Scale bars p1cm(AC,H), 5 mm (D),
2mm(EG), 0.5 mm (I,F).
two of the dispersed specimens under epiuorescence (g. 5G,
5I,5J). The pollen sacs are elongate-elliptic in shape (average,
0.70 mm #0.18 mm) and attached abaxially to the base of
the distal lamina (g. 5I5K). The long edge of the pollen sac
is oriented parallel with the microsporophyll stalk (g. 5I5K).
The number of pollen sacs per microsporophyll is not known
with certainty but, from the specimens at hand, appears to be
at least two, possibly three to ve (g. 5I,5J). Additional details
of the pollen sacs are not known, and pollen grains have not
been observed.
Seed cones. Ovuliferous cones are located terminally on
ultimate and penultimate shoots (g. 6), which bear leaves
morphologically similar to those on vegetative axes. Leaves
immediately below the cones are highly imbricate, densely ar-
ranged, and slightly smaller than leaves on the rest of the
shoot (g. 8A,8B,8D,8E,8I,8J). There is an abrupt transi-
tion from normal leaves to the basal ovuliferous complexes of
the ovuliferous cone (g. 6J). Cones are preserved in various
stages of maturity, with likely representatives of fully closed
(g. 6A,6C6E,6H) and open (g. 6D) cones. Branches bear-
ing closed cones are often distinctly curved immediately be-
low the cone (g. 6A,6B,6D,6I), suggesting that cones have
a preferential orientation (either erect or pendant) for facili-
tating pollination or later seed dispersal. Cones are ovate-
elongate with an acute apex when closed (g. 6A,6D) and
can appear almost globose when open, with LW ratios rang-
ing from 1.29 to 2.69 (average, 1.89; g. 6J). They range in
size from 12.5 to 35.8 mm (average, 22.5 mm) long and 7.6
to 17.0 mm (average, 11.9 mm) in maximum width, which is
generally located in the basal half of the cone. The central axis
of the cone is approximately 3.03.5 mm wide at the base,
decreasing distally to 1.52.0 mm wide (gs. 6E6H,7A),
and is surrounded by an estimated (24-)3045(-57) imbricate,
helically disposed ovuliferous complexes (gs. 6I,7A). The
ovuliferous complexes are dorsiventrally attened and coria-
ceous, with entire margins (gs. 6G,6I,6J,7H). There is no ev-
idence for a morphologically distinct bract and ovuliferous
scale. Ovuliferous complexes are decurrent along the central
axis for approximately 2.23.4 mm (gs. 6I,7A). In closed
cones, the ovuliferous complexes are imbricate and tightly ap-
pressed to each other (g. 6D,6E,6H). In open cones, the
ovuliferous complexes diverge from the axis at angles com-
monly between 607and 807(up to 907at the base of the cone
and lower angles apically) then curve upward at their mid-
region so that the broad distal face is roughly parallel to the axis
(gs. 6I,7A). The free portion of each complex consists of a nar-
row, basal stalk-like portion that is rhomboidal in cross section
(ca. 1.1 mm high and 1.5 mm wide) at its point of departure
from the cone axis (g. 7A) and 2.0 mm long before expanding
in width and turning upward to form a laminar distal face that is
broadly ovate in outline and tapers into a long acuminate apex
(g. 6E,6F,6J). The distal faces of ovuliferous complexes range
from 3.8 to 8.1 mm (average, 6.25 mm) in length and from 2.9
to 5.4 mm (average, 4.1 mm) in maximum width. The acumi-
nate tips of ovuliferous complexes are 1.62.9 mm (average,
2.2 mm) long and stout, and they curve outward from the cone
axis (gs. 6I,6
J,7A). At the apex of cones, these acuminate tips
protrude slightly beyond the apex, giving it a spiky appearance
(gs. 6A,6D,7F,7G). Each complex has a distinct thick abaxial
keel that extends from its base to its apex (g. 6E6H,6J). The
keel is widest, 1.3 mm wide, at the basal portion of the distal
face of each complex and tapers toward the apex (g. 6F,6G,
6J). The surface of the keel is distinctly rugose in texture and
protrudes approximately 1 mm from the surface of the ovulif-
erous complex (g. 6G,6H).
Seeds are borne medially on the adaxial surface of the
ovuliferous complexes (g. 7). An adaxial structure or mem-
branous lobes (povuliferous scale) are not observed in asso-
ciation with the seeds. In specimens for which the adaxial sur-
face of the ovuliferous complex is seen in face view, two
distinct seed impressions can be observed toward the middle
of the distal face (g. 7E7I). These impressions form dis-
tinct cavities that are oval to somewhat ovate-triangular with
rounded edges, approximately 1.02.0 mm (average, 1.4 mm)
long by 0.41.0 mm (average, 0.8 mm) at maximum width,
and show some variability in the relative positioning and ap-
parent orientation of the two seeds (g. 7E7I). In longitudi-
nal sections of the cone, seeds appear only slightly attened,
0.81.3 mm long and 0.50.9 mm high, and are inverted so
that the micropyle faces the axis of the cone (g. 7A,7B,
7D). One specimen shows the attachment of an inverted seed
to the ovuliferous complex (g. 7B). A lateral groove is also
observed on this specimen following the long axis of the seed,
which may represent a small lateral wing (g. 7B).
Comparisons and Discussion
Comparisons with Living and Extinct Taxa
The new fossil conifer, Austrohamia asfaltensis Contreras,
Escapa, Iribarren, et Cúneo, has a combination of vegetative
and reproductive characterssuch as the presence of uni-
veined, dorsiventrally attened leaves with decurrent leaf bases
and ovuliferous complexes that are organized in a typical cone
structure but that do not have a morphological distinction
between bract and ovuliferous scalethat support its assign-
ment to the Cupressaceae sensu lato to the exclusion of all other
recognized conifer families (Page 1990; Tomlinson and Takaso
2002; Farjon 2005; Eckenwalder 2009). Helical phyllotaxy and
having numerous (114) ovuliferous complexes per seed cone in-
dicate afnity to the taxodiaceous Cupressaceae rather than to
the Cupressaceae sensu stricto (Farjon 2005). Of the ve sub-
families composing the taxodiaceous grade, the combined pres-
ence of dorsiventrally attened, coriaceous ovuliferous com-
plexes and axillary pollen cones that are aggregated into dense
clusters indicates close afnities with the Cunninghamioideae
and Taiwanioideae subfamilies (Farjon 2005; Escapa et al.
2008a), which are the two earliest-diverging extant lineages
of the Cupressaceae crown group. Although the new species
described here shares several foliar features (e.g., univeined,
bifacially attened leaves that are oriented in one plane on ul-
timate shoots) with other taxodiaceous Cupressaceae genera
(e.g., Sequoia,Metasequoia Miki, Taxodium L.C. Richard,
Glyptostrobus Endlicher), these taxa are distinctly different
in having lignied, distally thickened to peltate ovuliferous
complexes and pollen cones that are solitary or not aggregated
into dense clusters of subterminal cones (Page 1990; Takaso
and Tomlinson 1990, 1992; Farjon 2005). Both Athrotaxis
D. Don and Cryptomeria D. Don differ from A. asfaltensis in
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 843
Fig. 6 Compression/impressions of seed cones of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov. AC, Seed cones
showing attachment to penultimate and ultimate shoots. DI, Closed cones. J, Open cone. A, Two seed cones attached to shoot system. Note
densely arranged, shorter leaves below cone (arrow; MPEF-Pb2452). B, Terminal, single seed cone attached to shoot (MPEF-Pb2904b). C, Two
cones attached to shoot system (MPEF-Pb1794a). D, Impression of surface of closed ovuliferous cone showing acute apex of cone with protrud-
ing acuminate apexes (a) of the terminal ovuliferous complexes. Note that the apexes of most complexes are not completely visible because of
their curvature away from the surface of the cone (MPEF-Pb1616). E, Seed cone showing external surface morphology, the shape of ovuliferous
complexes, and small leaves that transition to the base of the cone (MPEF-Pb2967). F, Surface of seed cone showing thick, prominent keels on
ovuliferous complexes (MPEF-Pb2444). G, Detail of Fshowing rugose texture of the thick abaxial keel (k; MPEF-Pb2444). H, Cone surface
showing thick keels (MPEF-Pb3877). I, Cone split longitudinally, showing internal structure of cone. The adaxial surface of ovuliferous com-
plexes (ad) and one complex showing the abaxial surface with keel (k) are visible. Note the decurrent base of the ovuliferous complexes on
the cone axis (arrow), the presence of the keel on the entire length of the complex, and the outwardly pointed apexes (a; MPEF-Pb2457). J, Open
cone showing general morphology of ovuliferous complexes. Note that the apex of the cone is incomplete (holotype; MPEF-Pb2463a). Scale bars p
1cm(AE,HJ), 5 mm (F), 2 mm (G).
most respects, particularly in the construction and variable
thickening of ovuliferous complexes and having awl-like to
scale-like leaves (Tomlinson and Takaso 2002; Farjon 2005;
Schulz and Stützel 2007). Furthermore, Athrotaxis spp. have
solitary terminal pollen cones, and Cryptomeria has pollen
cones that are not aggregated into dense clusters (Farjon 2005;
Eckenwalder 2009).
Living representatives of taiwanioid and cunninghamioid
lineages are restricted to three species: two species of Cun-
ninghamia (Cunninghamia lanceolata (Lamb.) Hook. and Cun-
ninghamia konishii Hayata) and Taiwania cryptomerioides
Hayata (Farjon 2005), but numerous morphologically similar
fossil species have been described from the Mesozoic of both
hemispheres, appearing as early as the Jurassic (e.g., Harris
1943, 1953, 1979; Miller 1975; Nishida et al. 1992; Saiki
and Kimura 1993; Yao et al. 1998; Escapa et al. 2008a; Brink
et al. 2009; Rothwell et al. 2011; Zhang et al. 2012; Serbet
et al. 2013; Atkinson et al. 2014a,2014b; Herrera et al. 2017).
The Patagonian taxon described here shares various combina-
tions of characters with the more completely known fossil taxa
and is most comparable to Austrohamia,Sewardiodendron,
and Elatides (tables 1, 2).
The new species is assigned to the extinct genus Austro-
hamia Escapa, Cúneo et Axsmith on the basis of numerous
shared features (table 1), most notably having two ovules po-
sitioned medially on each ovuliferous complex and the simi-
larity of the overall morphology of the ovuliferous complexes,
including the presence of an abaxial keel and the absence of a
morphologically distinct bract and ovuliferous scale (Escapa
et al. 2008a; Zhang et al. 2012). Furthermore, Austrohamia
species have pollen cones arranged in a cluster of few (two
to ve or more) pollen cones and helically arranged, bifacially
attened leaves that are often twisted into roughly planar ori-
entation (Escapa et al. 2008a; Dong et al. 2018).
Austrohamia asfaltensis is distinct from living and fossil
Taiwania and Cunninghamia species (table 3) in several re-
spects. Cunninghamia differs from A. asfaltensis by having
three ovules per ovuliferous complex, a small, membranous
lobed ovuliferous scale, and more pollen cones per cluster
(Farjon and Ortiz Garcia 2003; Farjon 2005; Serbet et al.
2013). Austrohamia asfaltensis is similar to Taiwania in not
showing a distinctive ovuliferous scale, having two ovules per
ovuliferous complex, and usually having fewer than ve pollen
cones per cluster (Farjon and Ortiz Garcia 2003; Farjon 2005,
2010; Lepage 2009). However, A. asfaltensis differs from
Taiwania but is more similar to Cunninghamia in the general
morphology (i.e., shape, apex) of the ovuliferous complexes,
the size of seed cones, and the number of ovuliferous complexes
per cone (tables 1, 3). Cunninghamia also has dorsiventrally
attened, spreading leaves that on ultimate shoots may be
curved to dispose in roughly planar orientation (at several
levels), similar to A. asfaltensis. The leaves in Cunninghamia,
however, are longer, lanceolate in shape, and narrowed at the
base and have serrate margins and sharply acute apexes (Page
1990; Farjon 2005; Serbet et al. 2013). Taiwania has distinct
leaf morphology, which varies between juvenile and adult
leaves. The leaves are helically disposed around shoots, bilat-
erally attened and tetragonal in cross section, falcate, and
awlescent with long, free blades in juveniles and shorter leaves
in adults, both with distinct leaf base cushions (Page 1990;
Farjon 2005; Lepage 2009). Leaves below cones are often
scale-like and have imbricate decurrent bases as opposed to
basal cushions.
Sewardiodendron laxum (Phillips) Florin was described from
the Middle Jurassic of central China based on compressions and
impressions of foliage, ovulate cones, and pollen cones (Yao
et al. 1998). Sewardiodendron laxum is similar to A. asfaltensis
in having pollen cone clusters consisting of fewer than eight
cones and in general aspects of foliage, including having bifa-
cially attened leaves with a high angle of departure and a lax
appearance, and a semiplanar orientation of leaves on ultimate
shoots (table 1). However, in Sewardiodendron, the leaves are
borne opposite and disposed in a double helix. Sewardio-
dendron also has distinctly larger seed cones, six ovules per
ovuliferous complex, and a small, but morphologically discrete,
lobed ovuliferous scale associated with the ovules (table 1).
The genus Elatides Heer comprises many species with vari-
able morphology, many of which share various features of
leaves, pollen cone clusters, and seed cones with the new species
(see tables 1, 2). The external morphology of seed cones of most
Elatides species is similar to that of A. asfaltensis. They all are
composed of helically arranged, coriaceous, and bifacially at-
tened ovuliferous complexes with acute to acuminate apexes,
occasionally with a distinct abaxial keel (tables 1, 2). Several
species (e.g., Elatides zhoui Shi, Leslie, Herendeen, Ichinnorov,
Takahashi, Knopf et Crane from the early Cretaceous of
Mongolia, Elatides harrisii Zhiyan from the Lower Cretaceous
of China, and Elatides bommeri Harris from the Lower Creta-
ceous of Belgium; Harris 1953; Zhou 1987; Shi et al. 2014) also
have seed cone sizes similar to A. asfaltensis. However, most
Elatides species have a distinct, small, membranous ovuliferous
scale, three or more seeds per ovuliferous complex, and leaves
that are rhomboidal in cross section and falcate in prole (tables 1,
2). These features clearly differentiate most Elatides species from
A. asfaltensis, with two exceptions. Elatides zhoui has dorsiven-
trally attened leaves that are helically disposed on shoots (Shi
et al. 2014). Elatides thomasii Harris from the middle Juras-
sic of Yorkshire, originally described by Harris (1979) and later
given a more detailed treatment by Schweitzer and Kirchner
(1996), does not have a recognizable free ovuliferous scale tip.
Interestingly, the morphological details of the ovuliferous com-
plexes of E. thomasii bear notable resemblance to A. asfaltensis
in having long acuminate apexes, a distinct abaxial keel, and
similar cone size (table 2), but otherwise, the species possesses
general characteristics typical of other Elatides species (e.g.,
three ovules per ovuliferous complex and leaves that are rhom-
boidal in cross section and falcate in prole).
Among fossil taxa with foliate ovuliferous complexes, the
only others known to not have distinct ovuliferous scale tips
are Stutzeliastrobus foliatus Herrera et al. from the Early Creta-
ceous of Mongolia (Herrera et al. 2017), the specimen described
as Cunninghamiostrobus yubariensis Stopes et Fujii by Ohana
and Kimura (1995) from the Late Cretaceous of Japan, and the
plants described by Seward (1895) and Harris (1953, 1979) as
Sphenolepis kurriana (Dunker) Schenk from the Early Creta-
ceous of Belgium (tables 46). Stutzeliastrobus foliatus differs
in most aspects of leaf morphology and in general morpholog-
ical features of the ovuliferous complexes such as the presence
of an abaxial keel and the long acuminate tip (Herrera et al.
2017). Cunninghamiostrobus yubariensis has very large cones
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 845
Fig. 7 Details of ovuliferous complexes of Austrohamia asfaltensis Contreras, Escapa, Iribarren, & Cúneo, sp. nov. AD, Longitudinal sec-
tions of ovuliferous complexes and seeds. EG, Variation in size and position/orientation of seed impressions on adaxial surfaces of ovuliferous
complexes. A, Likely near-mature cone split longitudinally, showing position of ovules/seeds. Note rhomboidal scar of ovuliferous complex (sc)
and seed impression on ovuliferous complex near the cone apex (arrow; MPEF-Pb2469/1619b). B, Detail of apical ovuliferous complexes with
seed impressions (s) in longitudinal section (left) and face view (right). The seed is attached (att) to the midregion of the ovuliferous complex (oc)
and inverted so that the micropyle (m) is facing the cone axis (MPEF-Pb2469/1619b). Illustrated as line drawing in H.C, Detail of counterpart of
lower left ovuliferous complex in Ashowing impression of ovule/seed positioned medially (MPEF-Pb1619a). D, Ovuliferous complex (oc) with
elliptic seed impression (s) in longitudinal section (MPEF-Pb2958). E, Adaxial surface of ovuliferous complex with two seed impressions (s) po-
sitioned in the lower middle part of the complex (MPEF-Pb2496b). F, Apical region of cone split longitudinally, showing upper part of the
with numerous ovuliferous complexes that fall well outside the
range of cone sizes for the plants described here (tables 1, 4).
Sphenolepis kurriana differs from A. asfaltensis by having a
small thickening on the adaxial surface of ovuliferous com-
plexes (forming a crest), two to six seeds per ovuliferous
complex, and scale-like leaves (Harris 1953).
Many other taxa have been erected based on anatomical
descriptions of permineralized or lignied seed cones, some of
which also have leaves, including Hubbardiostrobus cunning-
hamioides Atkinson, Rothwell et Stockey, Hughmillerites jud-
dii (Seward and Bancroft) Rothwell, Stockey, Mapes et Hilton,
Hughmillerites vancouverensis Atkinson, Rothwell et Stockey,
Mikasastrobus Saiki et Kimura, Parataiwania nihongii Nishida,
Ohsawa et Nishida,Acanthostrobus edenensis Klymiuk, Stockey
et Rothwell, three species of Cunninghamiostrobus (Cunning-
hamiostrobus goedertii Miller et Crabtree, Cunninghamiostro-
bus hueberi Miller, and C. yubariensis Stopes et Fujii), and
Pentakonos diminutus Herrera, Shi, Knopf, Leslie, Ichinnorov,
Takahashi, Crane et Herendeen (Stopes and Fujii 1910; Miller
1975, 1990; Miller and Crabtree 1989; Ohsawa et al. 1992,
1993; Saiki and Kimura 1993; Rothwell et al. 2011; Atkinson
et al. 2014a, 2014b; Klymiuk et al. 2015; Herrera et al. 2017).
All of these differ from A. asfaltensis in that they have more than
two ovules per ovuliferous complex and free ovuliferous scale
tips (either lobed or unlobed; tables 46). Additionally, leaves
in Hubbardiostrobus,Mikasastrobus,andAcanthostrobus are
tetragonal (to bilaterally attened) in cross section and generally
falcate in prole (tables 5, 6). Leaf morphology in C. goedertii
and C. hueberi ranges from dorsiventrally attened to rhom-
boidal in cross section (table 4; Miller 1975, 1990; Miller and
Crabtree 1989).
Scitistrobus duncaanensis Spencer, Mapes, Hilton et Roth-
well was recently described from the Middle Jurassic of western
Scotland based on an anatomically preserved ovuliferous cone
and has been suggested as a potential Cupressaceae stem taxon
(Spencer et al. 2015), although this position is not clear in phy-
logenetic analyses (Herrera et al. 2017). It is notably different
from the fossils described here and the other cunninghamioid-
like taxa mentioned above in that S. duncaanensis has distinctly
cylindrical ovuliferous cones composed of numerous ovulif-
erous complexes, each of which bears three ovuliferous scale
lobes that curve back toward the cone axis, with each lobe hold-
ing one seed distally (Spencer et al. 2015).
Species Diversity of Austrohamia
Two species of Austrohamia have been previously described
based on foliage, pollen cones, and seed cones: the type species
A. minuta Escapa, Cúneo et Axsmith from the Early Jurassic
Cerro Bayo locality in Patagonia (Pleinsbachian, ~183187 Ma),
Argentina (Escapa et al. 2008a), and A. acanthobractea Zhang,
DRozario, Wang, Li et Yao from the Daohugou ora in Inner
Mongolia (late Middle Jurassic, ~165 Ma), China (Zhang et al.
2012; Dong et al. 2018).
The differences between A. acanthobractea and A. minuta
are relatively minor, with the most distinct differences being
their leaf sizes and that A. acanthobractea has an acute or acu-
minate bract apex whereas A. minuta has an acute apex. The
dimensions of their seed and pollen cones are largely over-
lapping, and both species have a similar number of ovuliferous
complexes per cone (table 1). The new species described here is
consistent with the generic diagnosis for Austrohamia but with
amendment for cone size, as it has much larger seed cones than
both A. minuta and A. acanthobractea (table 1). The bimodal
distribution of seed cone sizes between the new taxon and those
previously described (most of which were also interpreted to be
mature or near mature but not yet having dispersed seeds) sug-
gests that these differences do not represent ontogenetic tra-
jectories, but rather, they represent real differences between
species. This is further supported by the greater number of
ovuliferous complexes per seed cone in A. asfaltensis (table 1).
The new taxon also differs from previously described species
A. minuta and A. acanthobractea in external details of ovu-
liferous complexes. Austrohamia asfaltensis has a large and more
well-dened abaxial keel than either preexisting taxon, with its
wide, protruding, and seemingly eshy keel extending from the
base of each complex to its apex. The keel in A. minuta and A.
acanthobractea is thinner and most noticeable toward the dis-
tal tip of each complex. The new taxon also has long acumi-
nate tips that curve outward from the cone, which is similar to
the specimens of A. acanthobractea described by Zhang et al.
(2012). Some differences in the orientation and placement of
seeds on the ovuliferous complex have been noted between A.
minuta and A. acanthobractea (g. 7I; Zhang et al. 2012). Spec-
imens of A. asfaltensis exhibit the full range of variability in seed
orientation and placement observed for the other two species
(g. 7I), and therefore, all three taxa are considered similar in
these respects (g. 7I).
Comparatively, the leaves of A. asfaltensis are larger than
those of A. minuta (after more precise measurements were made
for A. minuta), although they are similar to A. acanthobractea.
The leaves on both sterile and reproductive axes are spreading
(not incurved), with a consistently greater angle of departure
from the shoot axes.
Attached and dispersed pollen cones are known for all three
species. All species are similar in the aggregation of pollen cones
into distinct clusters, but A. asfaltensis has larger pollen cones
with more microsporophylls per cone (estimated to have over
twice as many; table 1). Details of the microsporangia are not
known for A. minuta.
adaxial surface of an ovuliferous complex with two distinct seed impressions (s; MPEF-Pb2484). Shape and position of impressions reconstructed
in line drawing in H.G, Compressed cone split obliquely to reveal adaxial surfaces and overall shape of ovuliferous complexes, showing
narrowed base (b) expanding to an ovate distal lamina with acuminate tip (a), bearing two seed impressions (ss; MPEF-Pb2901). H, Diagrams
of Austrohamia species shown to relative scale (A. minuta and A. acanthobractea redrawn from Escapa et al. 2008aand Zhang et al. 2012).
Adaxial seed placement of A. asfaltensis illustrated from specimens shown in F,G, and I. Abaxial surface based on specimen from Fand G.
Longitudinal section illustrated from specimen in B. Note the variation in seed position, orientation, and size for A. asfaltensis as reconstructed
from specimens, in comparison with A. acanthobractea and A. minuta (br pbract, k pkeel, mp pmicropyle, se pseed). I, Detail of
ovuliferous complex in Grotated, showing seed impressions (ss). Scale bars p5mm(A), 2 mm (B,C,EI), 1 mm (D).
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 847
Fig. 8 Pollen cone clusters in Cunninghamia and Taiwania.AF,Cunninghamia lanceolata (University of California Botanical Garden at
Berkeley, accession 65.0587). GN,Taiwania cryptomerioides (University of California Botanical Garden at Berkeley, accession 74.074).
O, Diagrammatic representations of the structure of pollen cone clusters. A, Mature pollen cone cluster after expansion of pollen cones. Note
the distinct bracts (br) associated with the pollen cones. B, Nearly mature pollen cone cluster prior to expansion of pollen cones and pollen re-
lease. C, Longitudinal section through pollen cone cluster in B, with several pollen cones removed to show structure of subtending bracts (br) and
ensheathing leaves (e) on interior cones. D, Top view of bract (br) and ensheathing leaves (e1e3) surrounding the axis of pollen cones removed
from cluster in B. Note the keeled and incurved apex of bract. Also note denticulate margin of microsporophylls. E, Side view of same pollen
cones as in Dshowing bracts (br) subtending each cone with ensheathing leaves (e). F, Several years of growth, showing continued elongation of
the shoot after dispersal of pollen and persistence of pollen cones on axis long after maturity. Note the blue waxy color of new foliage, where the
Overall, these comparisons suggest that the new taxon is best
accommodated within the previously existing genus Austro-
hamia as a new species, with amendment of the generic diagno-
sis to remove the maximum ovuliferous cone size and to adjust
the description of the pollen cone clusters. This is done in favor
of erecting a new genus for size and minor morphological differ-
ences. Parsimony-based phylogenetic analyses using an existing
morphological matrix (Shi et al. 2014; Herrera et al. 2017;
Dong et al. 2018) generally support the inclusion of the new
species in the genus Austrohamia; however, these analyses do
not resolve relationships among Austrohamia and other cun-
ninghamioid and taiwanioid conifers (results not shown). There
are numerous alternative congurations that are equally parsi-
monious given the limited characters included and the range of
morphological variation among taxa (e.g., Escapa et al. 2008a;
Herrera et al. 2017; Dong et al. 2018).
Notably, the occurrences of the three species of Austrohamia
are each separated by approximately 10 million years, yet they
are strikingly similar in morphology and are all found in lacus-
trine deposits. The species described here was deposited in a
large rift lake (see Figari et al. 2015) and shows evidence of
transportation, indicating that it grew near the lake or in the
surrounding area. The region has been suggested to have had
a wet, warm temperate climate, based on sedimentary evidence
coupled with the rich biota of the Cañadón Asfalto Formation,
which is among the most diverse and best known for the Juras-
sic of Gondwana (see Escapa et al. 2008b; Figari et al. 2016).
Austrohamia acanthobractea from the Daohugou ora of Inner
Mongolia grew in a highly diverse mountain-lake-forest envi-
ronment under a warm to cool temperate, moderately humid
climate (Na et al. 2017; Huang et al. 2018; Sun et al. 2018).
The broadly similar habitat and climate for these Austrohamia
species is likely related to their conserved morphology over long
time spans and geographic distance.
Morphological Aspects of Early-Diverging
Cupressaceae Lineages
The abundance of specimens of A. asfaltensis from a single lo-
cality has allowed for a better understanding of intraspecic
morphological variability and the growth habits and develop-
mental trajectories of various organs. The resulting reconstruc-
tion of A. asfaltensis from multiple organs has enabled compar-
ison with other fossil and living Cupressaceae over a broad set
of characters. Comparisons across species further demonstrate
a high degree of mosaicism among early cupressaceous taxa
(e.g., Atkinson et al. 2014a; Buczkowski et al. 2016), in which
different taxa are often delineated based on unique combina-
tions of characters rather than autapomorphies (table 16).
Although this mosaicism may indicate that the Cupressaceae
experienced a rapid morphological diversication, it has also
notoriously complicated the understanding of the early evolu-
tion of the family. In some cases, even intrageneric variation
in traits may be greater than the trait variation between genera
(tables 16). Furthermore, when considered across organs,
character mosaicism is even more extreme than can be recog-
nized by single organ comparisons. It is therefore important to
gain a better understanding of trends across organs. In the fol-
lowing sections, the morphologies of seed cones, pollen cones,
and foliage are discussed based on insights from comparison
of Austrohamia with other fossil and extant evidence and used
to explore commonalities and variation among Mesozoic
Cupressaceae.
Seed cones. The temporal pattern of appearance of seed
cone characteristics during the Mesozoic follows a trajectory
consistent with the pattern predicted by the order of divergence
of extant Cupressaceae lineages (e.g., Price and Lowenstein
1989; Gadek et al. 2000; Kusumi et al. 2000; Rothwell et al.
2011; Leslie et al. 2012; Mao et al. 2012; Yang et al. 2012;
Lu et al. 2014; Shi et al. 2014). The earliest forms that appear
in the Jurassic have cones with numerous bifacially attened,
coriaceous ovuliferous complexes that are composed mostly
of the bract (Harris 1943, 1953, 1979; Schweitzer and Kirchner
1996; Escapa et al. 2008a; Zhang et al. 2012; Wang et al.
2016). Cones with ovuliferous complexes that are woody, thick-
ened, and often peltate appear by the Early Cretaceous (e.g.,
Archangelsky 1963; Upchurch et al. 1994; Miller and Hickey
2010; Sokolova et al. 2017) and increase in diversity through
the Cretaceous and early Cenozoic (see Stockey et al. 2005).
Woody cones with a reduced number of ovuliferous complexes,
including valvate forms like those that occur in the Cupressoid
and Callitroid clades, appear by the Late Cretaceous (e.g.,
Samylina 1988; Boyd 1992; McIver 1994; McIver and Aulen-
back 1994; LePage 2003). Seed cones with morphology very
similar to extant taxa (and often assigned to living genera) occur
throughout the Cenozoic (e.g., McIver and Basinger 1989;
Kvaček et al. 2000; Liu and Basinger 2009; Wilf et al. 2009;
Paull and Hill 2010; He et al. 2012).
There is a high degree of similarity in the seed cones of Juras-
sic through Early Cretaceous taxa, particularly compared with
the morphological diversity observed for the entire extant fam-
ily. They primarily possess features that are now restricted to
most distal pollen cone clusters matured early in the same season as the new growth. G, Mature pollen cone cluster before expansion of pollen
cones. Note the distinct bracts associated with the pollen cones, as seen in C. lanceolata in gure 8A.H, Two mature pollen cones removed
from cluster along with their subtending bracts (br) and pairs of ensheathing leaves (e1, e2). I, Mature pollen cone cluster after expansion of
pollen cones. J, Longitudinal section through pollen cone cluster showing expanded central mass (cm), apical meristem (a) of shoot, and bracts
(br) subtending pollen cones. Note the smaller size of the central mass relative to Cunninghamia in C.K, Pollen cone cluster with front pollen
cone removed and one that has been stripped to its axis (left) showing subtending bract (br) and ensheathing leaves (e) at base of axis.
Ensheathing leaves are also visible on cone to the right. L, Rotated view of Kshowing the three ensheathing leaves (e1e3) attached at base
of pollen cone axis in the axil of the subtending bract (br). M, Growth habit of Taiwania pollen cone clusters showing numerous clusters on
tips of successive ultimate branches, in February 2015. N, Numerous pollen cone clusters freshly dispersed on ground beneath same tree from
M, in August 2015, after pollen release earlier in the season. O, Diagrams of pollen cone clusters showing similarity of structures, including the
central mass with apical meristem (black), bracts (brown), and ensheathing leaves (blue) at the base of each pollen cone. Scale bars p1cm(A,
B), 2 mm (C,D,H,J,K), 5 mm (G,I).
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 849
Table 1
Comparison of Relevant Fossil and Living Cupressaceae Taxa with Austrohamia asfaltensis (Austrohamia minuta to Elatides harrisii )
Austrohamia asfaltensis
Austrohamia
minuta
Austrohamia
acanthobractea
Sewardidendron
laxum Elatides williamsonii Elatides harrisii
Branching arrangement
and orientation
Alternate to subopposite,
one plane
Alternate to subopposite,
one plane
Alternate to subopposite,
one plane
Alternate to subopposite ? ?
Orientation of leaf blades
on ultimate vegetative
shoots
Semiplanar Semiplanar Semiplanar Semiplanar Helical Helical
Orientation of leaf blades
on reproductive shoots
Semiplanar Helical Helical Semiplanar Helical Helical
Prole of leaf tip relative
to shoot axis
Spreading (lax) Spreading (straight
or incurved)
Spreading (straight) Spreading (lax) Spreading (incurved) Spreading (straight or
sometimes incurved)
Leaf outline in transverse
section
Dorsiventrally attened Dorsiventrally attened Dorsiventrally attened Dorsiventrally attened Rhomboidal Rhomboidal
Leaf blade narrowed
at base
No No No No No No
Leaf margin Entire Entire Entire Entire Entire Denticulate
Leaf size (mm) 3.810 #.81.8 2.54#.4.6 411.5 #.61.3 10.022.0 #1.32.5 ? ca. 1015 #!1
Resin canals in leaf ? ? ? ? ? 1
Anticlinal walls of
epidermal cells
Straight ? Straight Straight Straight Straight
Leaf stomatal distribution ? ? Hypostomatic Hypostomatic Hypostomatic Epistomatic
Stomatal orientation Irregular? ? Irregular Irregular Irregular, transverse Irregular
Pollen cone position Borne axillary, aggregated
into terminal clusters
Borne axillary, aggregated
into clusters
Borne axillary, aggregated
into clusters
Borne axillary, aggregated
into clusters
Borne axillary, aggregated
into clusters
Borne axillary, aggregated
into clusters
No. pollen cones per
cluster
251447836?
Shoot elongation from
pollen cone cluster
Yes Yes ? Not observed Not observed Not observed
Modied leaves (bracts)
subtending pollen
cones
Yes Yes Yes ? Probably Yes
Ensheathing leaves at
base of pollen cone axis
? ? Yes? ? ? ?
Pollen cone size (mm) Immature 3.95.7 #
2.63.2; dispersed
8.013.0 #3.14.3
Expanded 5.6 #1.9 Immature 1.82.7 #
1.11.5; expanded 3.8
6.8 #1.62.3
Expanded 22.5 #36.5 Immature !16 long;
dispersed 1528 #57
Only immature known?
Microsporophylls per
pollen cone
Est. 35501(124 in f.v.) Est. 2639 (13 in l.s.) ? Est. ~501(130 partial
f.v.)
Est. 150 (138 in partial
f.v.)
?
Pollen sacs per microspo-
rophyll
21??3345
850
Seed cone size (mm) 1235 #717 57.8 #3.45.8 7.59.8 #5.07.5 Up to 65 #35 4060 #2025 1318 #1013
No. OCs Est. 2457 (1621 in
incomplete f.v.;
1619 in l.s.)
Est. 1218 (612 in l.s.
with partial f.v.)
!16 Numerous Numerous ?
OC morphology Foliate Foliate Foliate Foliate Foliate Foliate
OC abaxial keel Large, tapering toward
apex
Thin Thin Absent Absent Absent?
OC apex Acuminate Acute Acute or acuminate Acute Acute to acuminate Long acuminate
OC margin Entire Entire Entire Entire? Entire Denticulate
Distinct ovuliferous scale
a
Absent Absent Absent Small membranous
structure, lobed,
margin denticulate
Small membraneous
structure, lobed
Small membraneous
structure, margin
serrulate
Interseminal ridges Present, depressions Present, depressions Present, depressions? Absent Absent? Absent?
First division of OC
vascular trace vertical
? ? ? Absent ? ?
Resin canal system
b
??????
Resin canal branching
in bract
c
??????
No. resin canals at origin
of axial system
c
??????
No. resin canals in base
of OC at divergence
from axis
c
??2(1?)???
No. resin canals abaxial
to vasculature in distal
OC
??2(1?)???
Position of resin canals
relative to vascular
trace at level of seed
body
c
??????
No. seeds per OC 2 1 or 2 2 6 5 Probably 3
No. rows of seeds 1 1 1 1 1 ?
Seed lateral wings Probably ? Present Absent Present ?
Age Early Jurassic Early Jurassic Middle Jurassic Middle Jurassic Middle Jurassic Early Cretaceous
Location Patagonia, Argentina Patagonia, Argentina Inner Mongolia, China China Yorkshire China
Preservation Compression/impression Compression/impression Compression/impression Compression/impression Compression/impression Compression/impression
Sources. Harris (1943, 1979); Zhou (1987); Kurmann (1991); Yao et al. (1998); Escapa et al. (2008a); Zhang et al. (2012); Dong et al. (2018).
Note. OC povuliferous complex, l.s. plongitudinal section, f.v. pface view, est. pestimated. Estimated ranges for the numbers of ovuliferous complexes per seed cone and
microsporphylls per pollen cone were made based on gured specimens using the following guidelines: the number counted in face view represents two-thirds to one-half the total number,
and the number in longitudinal section represents one-half to one-third the total number.
a
Modied from Shi et al. (2014).
b
Modied from Atkinson et al. (2014b).
c
Modied from Klymiuk et al. (2015).
851
Table 2
Comparison of Relevant Fossil and Living Cupressaceae Taxa with Austrohamia asfaltensis (Elatides bommeri to Elatides sandaolingensis)
Characters Elatides bommeri Elatides zhoui Elatides curvifolia Elatides thomasii Elatides sandaolingensis
Branching arrangement and orientation Irregular Alternate, multiple planes Irregular Irregular ?
Orientation of leaf blades on ultimate
vegetative shoots
Helical Helical Helical Helical Helical
Orientation of leaf blades on reproductive
shoots
Helical Helical Helical Helical Helical
Prole of leaf tip relative to shoot axis Spreading (incurved) Spreading (incurved) Spreading (incurved) Spreading (incurved) Spreading (straight)
Leaf outline in transverse section Rhomboidal Dorsiventrally attened Rhomboidal Rhomboidal Dorsiventrally attened
Leaf blade narrowed at base No No No No No
Leaf margin Entire Denticulate Entire Entire Entire
Leaf size (mm) 13#1.3 611 #1.41.8 210 #.52.0 !5#.751810.5 #.81.8
Resin canals in leaf 1 1 ? 1 ?
Anticlinal walls of epidermal cells Straight Straight Straight Straight Straight
Leaf stomatal distribution Epistomatic Amphistomatic predominantly adaxial Amphistomatic ? Hypostomatic
Stomatal orientation Irregular, mostly
transverse
Irregular Mostly longitudinal,
some transverse
Irregular, mostly
transverse
Irregular, mostly trans-
verse
Pollen cone position ? Borne axillary, aggregated into clusters Single and terminating
shoot apex
? Borne axillary, aggre-
gated into clusters
No. pollen cones per cluster ? 79na?35
Shoot elongation from pollen cone cluster ? Yes na ? ?
Modied leaves (bracts) subtending pollen
cones
? Yes na ? ?
Ensheathing leaves at base of pollen cone
axis
??No??
Pollen cone size (mm) ? 2.32.7 #1.21.7 1122 #712 Expanded 1517 #34?
Microsporophylls per pollen cone ? ? Numerous ? ?
Pollen sacs per microsporophyll ? 3 2 (-3) ? 3
Seed cone size (mm) 1020 #11 1823 #1317 4050 #2528 1320 #1015 33.8 #8.6
No. OCs Est. 3869 (1928
in f.v.; 33 in l.s.)
150 Numerous? ? ~40
OC morphology Foliate Foliate Foliate Foliate Foliate
OC abaxial keel Probably present,
toward apex
Thin, mostly toward apex Present Present Absent
852
OC apex Obtuse, long spine-
like projection
Acuminate Acute Long acuminate Acute
OC margin Entire Denticulate ? ? Entire
Distinct ovuliferous scale
a
Small membranous
structure, lobed
Small membranous structure, entire
or lobed, margin mbriate
? Absent ?
Interseminal ridges Absent Absent ? Possibly? ?
First division of OC vascular trace vertical ? ? ? ? ?
Resin canal system
b
Continuous Continuous ? ? ?
Resin canal branching in bract
c
Absent Absent ? ? ?
No. resin canals at origin of axial system
c
0? ? ? ? ?
No. resin canals in base of OC at divergence
from axis
c
1? (13)? ? ? ?
No. resin canals abaxial to vasculature in
distal OC
13 ???
Position of resin canals relative to vascular
trace at level of seed body
c
Abaxial Abaxial ? ? ?
No. seeds per OC 3 46?3?
No. rows of seeds 1 1 ? 1 ?
Seed lateral wings Absent Present ? ? ?
Age Early Cretaceous Early Cretaceous Early Cretaceous Middle Jurassic Middle Jurassic
Location Belgium Mongolia Montana; Europe Yorkshire Northwestern China
Preservation Lignite (little
compression)
Lignite Compression/impression Compression/impression;
3-D (crystalline clay)
Compression/
impression
Sources. Harris (1953, 1979); Miller and LaPasha (1984); Schweitzer and Kirchner (1996); Shi et al. (2014); Wang et al. (2016).
Note. OC povuliferous complex, l.s. plongitudinal section, f.v. pface view, est. pestimated, na pnot applicable. Estimated ranges for the numbers of ovuliferous complexes per seed
cone and microsporphylls per pollen cone were made based on gured specimens using the following guidelines: the number counted in face view represents two-thirds to one-half the total
number, and the number in longitudinal section represents one-half to one-third the total number.
a
Modied from Shi et al. (2014).
b
Modied from Atkinson et al. (2014b).
c
Modied from Klymiuk et al. (2015).
853
Table 3
Comparison of Relevant Fossil and Living Cupressaceae Taxa with Austrohamia asfaltensis (Cunninghamia taylorii to Taiwania c.f. T. cryptomeroides)
Cunninghamia taylorii
Cunninghamia
konishii Cunninghamia lanceolata Taiwania cryptomeroides
Taiwania c.f.
T. cryptomeroides
Branching arrangement and orientation Pseudowhorl Pseudowhorl, higher
order plagiotropic
Pseudowhorl, higher order
plagiotropic
Alternate, irregular Alternate, irregular
Orientation of leaf blades on ultimate
vegetative shoots
Semiplanar, helical Semiplanar, helical Semiplanar, helical Helical Helical
Orientation of leaf blades on
reproductive shoots
Helical Helical Semiplanar/helical Helical Helical
Prole of leaf tip relative to shoot axis Spreading (incurved) Spreading (incurved) Spreading Spreading (incurved,
straight)
Spreading (incurved,
straight)
Leaf outline in transverse section Dorsiventrally attened
to rhomboidal
Dorsiventrally
attened
Dorsiventrally attened Rhomboidal to bilaterally
attened, triangular
Rhomboidal to bilaterally
attened, triangular
Leaf blade narrowed at base ? Yes Yes No No
Leaf margin Denticulate Denticulate Denticulate Entire Entire
Leaf size (mm) 820 #1.53.5 2030 #233060 #3536#1.23!6#!2
Resin canals in leaf 3 13131(2) ?
Anticlinal walls of epidermal cells Appearing undulate Appearing undulate Appearing undulate Straight ?
Leaf stomatal distribution Hypostomatic Amphistomatic Amphistomatic, predominantly
abaxial
Amphistomatic, predomi-
nantly adaxial
?
Stomatal orientation Mostly longitudinal Mostly longitudinal Mostly longitudinal Mostly longitudinal ?
Pollen cone position Borne axillary, aggregated into
clusters
Borne axillary, aggre-
gated into clusters
Borne axillary, aggregated
into clusters
Borne axillary, aggregated
into clusters
?
No. pollen cones per cluster 117 142011630 27?
Shoot elongation from pollen
cone cluster
Not observed (but probable) Yes Yes No ?
Modied leaves (bracts) subtending
pollen cones
Yes Yes Yes Yes ?
Ensheathing leaves at base
of pollen cone axis
Yes Yes Yes Yes ?
Pollen cone size (mm) ? Expanded 1015 #
34
Expanded 1020 #35 Expanded 47.2 #2.43?
Microsporophylls per pollen cone ? 5881; 30100 5286 (avg. 65); 30100 1220 (avg. 15) ?
Pollen sacs per microsporophyll ? 242424?
854
Seed cone size (mm) 30 #23 1530 #1520(-35) 2545 #2535(-45) 825 #312 714 #59
No. OCs Numerous 3265 4772 1436 ?
OC morphology Foliate Foliate Foliate Foliate Foliate
OC abaxial keel ? Thin, mostly toward
apex
Thin, mostly toward apex Absent Absent
OC apex Acuminate Acute, pointed Acute, pointed Obtuse, mucronate Obtuse, mucronate
OC margin Ornamented Denticulate Denticulate Entire Entire
Distinct ovuliferous scale
a
Small membranous structure,
lobed, margin mbriate
Small membranous
structure
Small membranous structure, entire
or lobed, margin mbriate
Absent Absent
Interseminal ridges Absent Absent Absent Absent ?
First division of OC vascular
trace vertical
Present ? Present Absent ?
Resin canal system
b
Continuous Continuous Continuous Discontinuous ?
Resin canal branching in bract
c
Present Present Present Present ?
No. resin canals at origin
of axial system
c
1? 1 1?
No. resin canals in base of OC
at divergence from axis
c
1? ? 1 1 ?
No. resin canals abaxial to vasculature
in distal OC
Many (16) ? Many (110) Many ?
Position of resin canals relative to
vascular trace at level of seed body
c
Abaxial Abaxial Abaxial Abaxial ?
No. seeds per OC 3 3 3 2 ?
No. rows of seeds 1 1 1 1 ?
Seed lateral wings Present Present Present Present Present
Age Late Cretaceous Extant Extant Extant Early Cretaceous
Location Near Alberta, Canada China, Laos, Taiwan,
Vietnam
China, Laos, Taiwan, Vietnam Southwest China,
Myanmar, Taiwan,
Vietnam
Alaska
Preservation Permineralized na na na Compression / impression
Sources. Liu and Su (1983); Farjon and Ortiz Garcia (2003); Farjon (2005); Schulz et al. (2005); Schulz and Stützel (2007); Eckenwalder (2009); Lepage (2009); Ma et al. (2009); Serbet
et al. (2013); Shi et al. (2014).
Notes. OC povuliferous complex, na pnot applicable, avg. paverage. Estimated ranges for the numbers of ovuliferous complexes per seed cone and microsporphylls per pollen cone
were made based on gured specimens using the following guidelines: the number counted in face view represents two-thirds to one-half the total number, and the number in longitudinal section
represents one-half to one-third the total number.
a
Modied from Shi et al. (2014).
b
Modied from Atkinson et al. (2014b).
c
Modied from Klymiuk et al. (2015).
855
Table 4
Comparison of Relevant Fossil and Living Cupressaceae Taxa with Austrohamia asfaltensis (Cunninghamiostrobus hueberi to Hughmillerites juddii)
Cunninghamiostrobus
hueberi
Cunninghamiost-robus
yubariensis Cunninghamiost-robus goedertii
Hughmillerites
vancouverensis Hughmillerites juddii
Branching arrangement and orientation ? ? ? ? ?
Orientation of leaf blades on ultimate vegeta-
tive shoots
Helical ? Semiplanar, helical ? ?
Orientation of leaf blades on reproductive
shoots
Helical ? Helical Helical ?
Prole of leaf tip relative to shoot axis ? ? Spreading (some incurved) Spreading (incurved) ?
Leaf outline in transverse section Dorsiventrally attened ? Dorsiventrally attened, some
transversely rhombic
Triangular to dorsiven-
trally attened
Rhomboidal
Leaf blade narrowed at base ? ? Yes No? ?
Leaf margin ? ? Denticulate Entire ?
Leaf size (mm) 18#23.5 ? Up to 23 #33.5 3 #1.3 ?
Resin canals in leaf 3 ? 1511
Anticlinal walls of epidermal cells ? ? Straight ? ?
Leaf stomatal distribution Amphistomatic ? Hypostomatic, amphistomatic ? ?
Stomatal orientation ? ? Irregular, mostly transverse ? ?
Pollen cone position ? ? ? ? ?
No. pollen cones per cluster ? ? ? ? ?
Shoot elongation from pollen cone cluster ? ? ? ? ?
Modied leaves (bracts) subtending
pollen cones
?? ? ??
Ensheathing leaves at base of pollen cone axis ? ? ? ? ?
Pollen cone size (mm) ? ? ? ? ?
Microsporophylls per pollen cone ? ? ? ? ?
Pollen sacs per microsporophyll ? ? ? ? ?
Seed cone size (mm) 3035 #25 165 #25 40 #3045 Up to 21 #20 147 #2238
No. OCs Est. 4466 (22 in l.s.) Numerous, 150 Numerous Numerous? ?
OC morphology Foliate Foliate Foliate Foliate Foliate
OC abaxial keel ? Thin ? Absent? Absent?
OC apex ? Broadly acute to
obtuse, pointed
Acute Attenuate Tapering, pointed
856
OC margin ? Entire ? ? ?
Distinct ovuliferous scale
a
Small membranous structure,
entire or lobed
Absent Small membranous structure 3 small membranous
lobes, margin?
3 small membranous
lobes, margin?
Interseminal ridges Absent Present, socket-like
cavities
Absent Present Present
First division of OC vascular trace vertical Present Present Present Absent Absent
Resin canal system
b
Continuous Continuous Continuous Discontinuous Discontinuous
Resin canal branching in bract
c
Present Present? Present Absent Absent
No. resin canals at origin of axial system
c
31133511
No. resin canals in base of OC at divergence
from axis
c
31133511
No. resin canals abaxial to vasculature
in distal OC
93 1215 131
Position of resin canals relative to vascular
trace at level of seed body
c
Adaxial and abaxial Abaxial Adaxial and abaxial Adaxial and abaxial Adaxial and abaxial
No. seeds per OC 3 3 3(-4) 3 3
No. rows of seeds 1 1 1 1 1
Seed lateral wings Present Absent ? Present ?
Age Early Cretaceous Late Cretaceous Oligocene Early Cretaceous Late Jurassic
Location California Upper Yezo Group,
Japan
Washington Vancouver Island,
British Columbia
Scotland
Preservation Permineralized Permineralized Permineralized Permineralized Permineralized
Sources. Rothwell et al. (2011); Atkinson et al. (2014a, 2014b); Spencer et al. (2015); Herrera et al. (2017).
Notes. OC povuliferous complex, l.s. plongitudinal section. Estimated ranges for the numbers of ovuliferous complexes per seed cone and microsporphylls per pollen cone were made
based on gured specimens using the following guidelines: the number counted in face view represents two-thirds to one-half the total number, and the number in longitudinal section represents
one-half to one-third the total number.
a
Modied from Shi et al. (2014).
b
Modied from Atkinson et al. (2014b).
c
Modied from Klymiuk et al. (2015).
857
Table 5
Comparison of Relevant Fossil and Living Cupressaceae Taxa with Austrohamia asfaltensis (Hubbardiostrobus cunninghamioides to Stutzeliastrobus foliatus)
Hubbardiostrobus
cunninghamioides Acanthostrobus edenensis
Scitistrobus
duncaanensis Pentakonos diminutus Stutzeliastrobus foliatus
Branching arrangement and orientation Alternate ? ? ? ?
Orientation of leaf blades on ultimate
vegetative shoots
Helical ? ? ? Helical
Orientation of leaf blades on reproductive
shoots
Helical Helical ? ? Helical
Prole of leaf tip relative to shoot axis Spreading (incurved) Spreading (incurved) ? ? Spreading (incurved)
Leaf outline in transverse section Rhomboidal Rhomboidal ? ? Square to triangular and
dorsiventrally attened
Leaf blade narrowed at base No No? ? ? No
Leaf margin ? Entire? ? ? Entire
Leaf size (mm) 47#1.42.5 18#1.7 ? ? 1.73.3 #1.52.8
Resin canals in leaf 3 1 ? ? 1
Anticlinal walls of epidermal cells ? ? ? ? Straight
Leaf stomatal distribution ? Hypostomatic ? ? Amphistomatic
Stomatal orientation ? ? ? ? Irregular
Pollen cone position ? ? ? ? ?
No. pollen cones per cluster ? ? ? ? ?
Shoot elongation from pollen cone cluster ? ? ? ? ?
Modied leaves (bracts) subtending
pollen cones
?? ? ? ?
Ensheathing leaves at base of pollen
cone axis
?? ? ? ?
Pollen cone size (mm) ? ? ? ? ?
Microsporophylls per pollen cone ? ? ? ? ?
Pollen sacs per microsporophyll ? ? ? ? ?
Seed cone size (mm) 1315 #425#89130 #7.5 6.66.7 #4.76.4 732 #615
No. OCs 140 Numerous, est. 150 Numerous 12530 3070
OC morphology Foliate Foliate Foliate Foliate Foliate
OC abaxial keel ? Possibly? Weakly, toward apex Absent Present?
OC apex ? Long acuminate Acuminate Obtuse, mucronate Obtuse, mucronate
858
OC margin ? ? Entire Toothed Erose distally, entire to
minutely toothed proximally
Distinct ovuliferous scale
a
3 small membranous
lobes, margin?
Small membranous struc-
ture, entire, margin?
3 lobes that are fully
separate at divergence
Small membraneous structure,
entire, margin minutely toothed
Absent
Interseminal ridges Absent Absent Absent Absent Absent
First division of OC vascular trace vertical Absent Absent Absent ? ?
Resin canal system
b
Discontinuous Continuous Discontinuous ? Continuous
Resin canal branching in bract
c
Absent Present Present ? Absent
No. resin canals at origin of axial system
c
01 0 ? ?
No. resin canals in base of OC
at divergence from axis
c
13 23? ?
No. resin canals abaxial to vasculature in
distal OC
799 4 ? 1
Position of resin canals relative to vascular
trace at level of seed body
c
Abaxial Abaxial Abaxial ? Abaxial
No. seeds per OC 3 (2-) 343 5 24
No. rows of seeds 1 1 1 2 12
Seed lateral wings Present Present Present Present Present, distal and asymmetrical
Age Early Cretaceous Late Cretaceous Middle Jurassic Early Cretaceous Early Cretaceous
Location Vancouver Island,
British Columbia
Vancouver Island, British
Columbia
Isle of Sky, Scotland Mongolia Mongolia
Preservation Permineralized Permineralized Permineralized Lignite Lignite
Sources. Miller (1975, 1990); Miller and Crabtree (1989); Nishida et al. (1992); Ohana and Kimura (1995); Klymiuk et al. (2015).
Notes. OC povuliferous complex, est. pestimated. Estimated ranges for the numbers of ovuliferous complexes per seed cone and microsporphylls per pollen cone were made based on
gured specimens using the following guidelines: the number counted in face view represents two-thirds to one-half the total number, and the number in longitudinal section represents one-half
to one-third the total number.
a
Modied from Shi et al. (2014).
b
Modied from Atkinson et al. (2014b).
c
Modied from Klymiuk et al. (2015).
859
Table 6
Comparison of Relevant Fossil and Living Cupressaceae Taxa with Austrohamia asfaltensis (Mikasostrobus hokkaidoensis to Athrotaxis selaginoides)
Mikasostrobus hokkaidoensis Parataiwania nihongii Sphenolepis kurriana Athrotaxis selaginoides
Branching arrangement and orientation ? ? Alternate, irregular Irregular
Orientation of leaf blades on ultimate
vegetative shoots
Helical ? Helical, appressed Helical
Orientation of leaf blades on
reproductive shoots
Helical ? Helical, appressed Helical
Prole of leaf tip relative to shoot axis ? ? Appressed Spreading (incurved)
Leaf outline in transverse section Rhomboidal ? Triangular Dorsiventrally attened and keeled (triangular
to rhomboidal at base)
Leaf blade narrowed at base No ? No No
Leaf margin ? ? Entire Entire
Leaf size (mm) 13#!2?.72.5 #.51.0 5.98.2 #1.42.45
Resin canals in leaf ? ? 1 3
Anticlinal walls of epidermal cells ? ? Straight, often slightly
sinuous
Straight
Leaf stomatal distribution Hypostomatic ? Hypostomatic Amphistomatic, predominantly adaxial
Stomatal orientation ? ? Transverse Longitudinal
Pollen cone position ? ? ? Single and terminating shoot apex
No. pollen cones per cluster ? ? ? na
Shoot elongation from pollen cone cluster ? ? ? na
Modied leaves (bracts) subtending
pollen cones
??? na
Ensheathing leaves at base of pollen cone axis ? ? ? Yes?
Pollen cone size (mm) ? ? ? 24#24
Microsporophylls per pollen cone ? ? ? 3959
Pollen sacs per microsporophyll ? ? ? 15 (avg. 2)
Seed cone size (mm) 2540 #2035 22 #16 1214 #710 1021 #821
No. OCs 140 Est. 3860 (119 in l.s.) Est. ~3648 (24 in f.v.) 2036
OC morphology Foliate Foliate Thin with slight adaxial
thickened edge
Thin with adaxial thickening
OC abaxial keel Absent? No No No
860
OC apex Obtuse, mucronate Tapered Obtuse, pointed Long tapering acute, positioned apically
on distal head
OC margin Entire Entire Entire Entire
Distinct ovuliferous scale
a
Small membranous structure,
entire, margin entire
Very small membranous
structure, entire, margin?
Probably absent Adaxial swelling distal to seeds
Interseminal ridges Absent Absent Present, grooves
with ridges
Absent
First division of OC vascular trace vertical Absent Absent Absent . . .
Resin canal system
b
Continuous? Discontinuous Discontinuous? Continuous?
Resin canal branching in bract
c
Present Present ? Present
No. resin canals at origin of axial system
c
110 1
No. resin canals in base of OC
at divergence from axis
c
3 1(-3) 233
No. resin canals abaxial to vasculature
in distal OC
1014 113 3 Many (110)
Position of resin canals relative to vascular
trace at level of seed body
c
Abaxial Abaxial Abaxial Adaxial and abaxial
No. seeds per OC 4542636
No. rows of seeds 1 1 121
Seed lateral wings Present Present Present Present
Age Late Cretaceous Late Cretaceous Early Cretaceous Extant
Location Upper Yezo Group, Japan Upper Yezo Group, Japan Wealden Formation,
Belgium
Tasmania, Australia
Preservation Permineralized Permineralized Lignite na
Sources. Seward (1895); Harris (1953); Saiki and Kimura (1993); Farjon (2005); Schulz et al. (2005); Schulz and Stützel (2007); Herrera et al. (2017).
Notes. OC povuliferous complex, l.s. plongitudinal section, f.v. pface view, est. pestimated, avg. paverage, na pnot applicable. Estimated ranges for the numbers of ovuliferous
complexes per seed cone and microsporphylls per pollen cone were made based on gured specimens using the following guidelines: the number counted in face view represents two-thirds to
one-half the total number, and the number in longitudinal section represents one-half to one-third the total number.
a
Modied from Shi et al. (2014).
b
Modied from Atkinson et al. (2014b).
c
Modied from Klymiuk et al. (2015).
861
the earliest-diverging extant taxa Cunninghamia and Taiwania
namely, ovuliferous complexes that are foliate/coriaceous and
bifacially attened. There is, however, appreciable variation in
the overall size and shape of seed cones, the number of ovules,
the number and general morphology of the ovuliferous com-
plexes (apex shape, keel), and the presence and morphology of
a membraneous, free ovuliferous scale tip. In cases where cones
are permineralized, anatomical characters have provided a
wealth of additional information, such as the course of vascula-
ture and resin canals, although variability can be difcult to as-
sess, and the corresponding surface morphology may not be well
understood (Escapa and Leslie 2017).
Among the Jurassic-Cretaceous species, A. minuta has been
considered notable for the small size of its seed cones in rela-
tion to other Cupressaceae, and this characteristic has been
emphasized in supporting a closer relationship to Taiwania
than to Cunninghamia (Shi et al. 2014). The signicantly larger
seed cones of A. asfaltensis demonstrate that seed cone size is
not a dening feature of the genus but rather the expression of
a range of variation (probably to an extent environmentally
driven) that commonly exists among closely related plants with
differing ecologies and/or environmental conditions (e.g., Cu-
pressus L.; Farjon 2005). Therefore, while the absolute sizes
of seed cones may be important in species level differentiation
(as with extant plants), it is unclear whether they provide much
systematic importance for understanding suprageneric relation-
ships within families. Instead, the number of parts, such as the
number of bract-scale complexes, may provide more phyloge-
netically useful information on relationships (Shi et al. 2014).
It has long been recognized that the extant Cupressaceae ex-
hibit a general trend toward reduction in the number of parts of
the seed cone (despite having a wide range of absolute cone size
for any given number of ovuliferous complexes; e.g., Ecken-
walder 1976; Farjon and Ortiz Garcia 2003; Leslie 2011). The
earliest-diverging extant taxa and older fossil Cupressaceae also
tend to have numerous ovuliferous complexes (tables 16), and
several Late Jurassic to Cretaceous taxa have a more cylindrical
shape (greater LW ratio) than extant relatives (e.g., Atkinson
et al. 2014a; Klymiuk et al. 2015; Spencer et al. 2015). These
characteristics have been linked to the more cylindrical cones
of Voltziales and suggested to have been the ancestral condi-
tion (Leslie 2011; Spencer et al. 2015). Although A. minuta
and A. acanthobractea may be notable among Jurassic Cupres-
saceae for having relatively fewer complexes per cone and
hence a smaller LW ratio (i.e., more globose to elliptic), A.
asfaltensis has distinctly ovoid/ellipsoidal cones and is similar
in its number of ovuliferous complexes to many other cun-
ninghamioidtaxa (tables 16). The three Jurassic Austroha-
mia species thus complicate the narrative of cylindrical cones
being the ancestral condition for the family with subsequent
progressive reduction in number of parts. Of course, much re-
mains unknown about potential sister or stem lineages be-
tween Sciadopitys,Taxaceae s.l., and Cupressaceae. This in-
formation, together with more robust phylogenetic analyses,
would help clarify whether cylindrical cones with numerous
complexes represent the ancestral/pleisomorphic condition for
the basalmost lineages of Cupressaceae or whether they are
simply a unique feature of several taxa.
In regard to the general external morphology of the ovu-
liferous complexes, attenuated apexes and distinct abaxial keels
appear to be fairly common among Jurassic and Cretaceous
Cupressaceae (see tables 16). The systematic and functional
importance of both of these characters have yet to be explored,
and comparative inference is complicated by the fact that these
traits are not expressed with such prominence among extant
Cupressaceae. Although no living taxa exhibit the long, atten-
uated apexes on their mature ovuliferous complexes, several
have abaxial keels (Cunninghamia,Athrotaxis selaginoides D.
Don). However, their keels are much less distinct than those ob-
served in fossil taxa, appearing mostly toward the apex of the
bract. The keels in A. asfaltensis are notably thick and extend
along the full length of each ovuliferous complex. Although it
is unclear what the functional attributes of a thick, prominent
keel may have been, one might speculate that the keel served
as structural support for the relatively thin ovuliferous com-
plexes as seeds grew and matured. The wrinkled texture of
the thick, protruding keel can give the impression that it was
somewhat eshy, which also raises the possibility that it served
a function in closing and opening the cone, mediated through
turgor of the keel.
Another character of fossil taxa that is not expressed among
the living representatives is the interseminal ridges separating
seeds on the adaxial surface of the ovuliferous complexes. In
the Cupressaceae, this feature has been described mainly in
permineralized specimens, where the ridges can be recognized
in transverse sections of the ovuliferous complex (Rothwell
et al. 2011; Atkinson et al. 2014b). Several authors have also
described socket-like cavities that bear the seeds, separated by
ridges (Harris 1953; Ohana and Kimura 1995; Spencer et al.
2015). These ridges and cavities most likely represent impres-
sions of the seed body in the adaxial surface of the complex,
which remain visible even after seed dispersal. This situation
is quite distinct from the at adaxial surfaces of ovuliferous
complexes in living Cupressaceae taxa, including Cunningha-
mia and Taiwania. In these cases, after seed dispersal, the seed
position and number can be determined only from seed attach-
ment scars rather than from recessed impressions. The distinct
seed impressions in Austrohamia are interpreted here to be the
same as the socket-like cavities and interseminal ridges identi-
ed in the permineralized cones, thereby expanding the known
occurrence of this character among the early Cupressaceae and
extending its recognition to compression/impression material.
The absence of a morphologically discrete ovuliferous scale
in Austrohamia has been inuential in the assessment of its re-
lationship with other fossil and living taxa. In general, the pres-
ence of small membraneous ovuliferous scale tips in Cunning-
hamia and many Mesozoic fossil Cupressaceae (tables 16) has
been heavily emphasized in ideas regarding the evolution of
Cupressaceae (Farjon and Ortiz Garcia 2003; Schulz and Stüt-
zel 2007; Rothwell et al. 2011; Atkinson et al. 2014a; Spencer
et al. 2015). The free ovuliferous scale tips are thought to repre-
sent a stage in the hypothesized reduction series of the ovu-
liferous scale (see Rothwell et al. 2011) and are often considered
a synapomorphy of the cunninghamioid clade (sensu Shi et al.
2014; Herrera et al. 2017). The absence of the ovuliferous scale
tips in Austrohamia has thus resulted in it being closely com-
pared with Taiwania and excluded from the cunninghamioid
clade. Interestingly, several other early taxa do not possess
this feature but otherwise share numerous, or most, features
of seed cones with cunninghamioids (e.g., E. thomasii and
862 INTERNATIONAL JOURNAL OF PLANT SCIENCES
C. yubariensis sensu Ohana and Kimura 1995). It is also worth
noting that variable expression of the free tips, including the
degree of fusion between lobes, has been documented within
species (e.g., E. zhoui,Cunninghamia), and in extant Cunning-
hamia, the tips have been noted to change with ontogenetic
stage (often fusesto form a ridge at maturity; Farjon and
Ortiz Garcia 2003). The similarities, or differences, in seed cone
morphology between taxa do not naturally fall into morpholog-
ical groupings coinciding with the presence/absence of this
character but rather exhibit marked patterns of homoplasy
and mosaicism that are difcult to reconcile (see tables 16).
Many morphological and anatomical characters seen in these
taxa are not currently included in available morphological ma-
trices and have therefore yet to be evaluated in a phylogenetic
context. However, it seems that for the ovuliferous scale tips
to be an unambiguous synapomorphy of cunninghamioids, thus
excluding the taxa without the scale tips from the clade, there
must exist signicant homoplasy in many other seed cone, leaf,
and pollen cone characters. Alternatively, given that the free
ovuliferous scale tips represent a single character, it is possible
that the expression of the free tips (the timing or extent) is a labile
trait among early cupressaceous taxa (see also the discussions
of heterochrony and organ development in Spencer et al. 2015
and Rothwell et al. 2011).
Pollen cone aggregations. Aspects of pollen cones and their
disposition show remarkable similarity among the earliest Cu-
pressaceae. In contrast to leaf and seed cone characteristics,
aspects of pollen cones appear to be more conserved among
taxa (Leslie 2011; Buczkowski et al. 2016), although there are
notable trends across clades in the Cupressaceae that are useful
in the assessment of afnities (Schulz et al. 2014).
The similarity of Jurassic through Cenozoic fossil pollen cone
clusters to those of extant Cunninghamia, in particular, has
been well recognized (Escapa et al. 2008a; Serbet et al. 2013;
Shi et al. 2014; Buczkowski et al. 2016), and such clusters are
also shared with Taiwania (Liu and Su 1983; Farjon 2005;
Dong et al. 2018). The basic construction of the clusters is sim-
ilar between Cunninghamia and Taiwania, although there are
differences in the absolute size of the clusters, the number of pol-
len cones per cluster, and the number of microsporophylls per
pollen cone (table 3; summarized in g. 8Oillustrations). Ex-
amination of the living representatives provides a solid compar-
ative foundation for understanding the fossil taxa. The general
construction of the clusters is as follows: Pollen cones are borne
in axillary position at the end of a shoot (g. 8A8C,8G8J).
Each pollen cone is subtended by a keeled bract (g. 8A,8I),
and there are several scale-like ensheathing leaves(commonly
three in Cunninghamia and two or three in Taiwania) arising at
the base of each pollen cone axis (g. 8D,8K,8L). Each of these
repeated units (bract 1ensheathing leaves 1pollen cone) occurs
at successive nodes in a helix, with extremely short internodes,
resulting in a dense cluster surrounding an expanded central
mass of tissue (g. 8C,8
J). The pollen cones themselves consist
of a central axis with helically arranged microsporophylls. Var-
iation between Taiwania and Cunninghamia is mostly due to the
size and number of parts. Taiwania has smaller pollen cones
with fewer microsporophylls per cone and fewer pollen cones
per cluster than Cunninghamia (27and14201, respectively;
g. 8A,8B,8G,8I). The central mass of Taiwania clusters is also
notably smaller than that of Cunninghamia (g. 8C,8J), which is
not surprising given that the central mass should become more
prominent when there is a greater number of pollen cones. In
both taxa, the apex of the shoot supporting the pollen cone clus-
ter is not terminated by a pollen cone, but instead, the shoot apex
remains distinct in the center of the cluster, protected by several
overlapping leaves (g. 8C,8J). In Cunninghamia, the shoot
apex regularly resumes normal vegetative growth following pol-
len release early in the growth season. This can result in succes-
sive seasonal increments of leaves alternating with the persistent
remains of the pollen cone clusters (mostly bracts and scale-like
leaves, as the delicate pollen cones eventually break off; g. 8F).
This can also result in the lateral appearance of pollen cones on
older shoots. In Taiwania, however, the shoots supporting the
pollen cone clusters have not been observed to resume vegetative
growth (D. Contreras, personal observation), and instead, these
shoots are shed shortly after pollen dispersal (g. 8M,8N).
In the fossil record, pollen cone clusters are denitively ob-
served in all Austrohamia species, Elatides williamsoni Harris,
E. harrissi,E. zhoui,E. sandaolingensis Wang et Sun, Sewar-
diodendron laxum,Cunninghamia taylorii,andCunninghamia
beardii Buczkowski, Stockey, Atkinson et Rothwell (Harris
1943; Zhou 1987; Yao et al. 1998; Escapa et al. 2008a;Serbet
et al. 2013; Buczkowski et al. 2016; Wang et al. 2016; Dong
et al. 2018). Of these, all but C. taylorii and C. beardii have
fewer than nine pollen cones per cluster. Where preservation
is good enough to assess details, the pollen cones are each ax-
illary in position and subtended by specialized bracts (e.g.,
Austrohamia). The large number of pollen cones per cluster
seen in Cunninghamia appears to be a characteristic unique
to the genus and is observed in the earliest fossil Cunning-
hamia representatives from the Cretaceous (Serbet et al. 2013;
Buczkowski et al. 2016). Among the fossil taxa, there is vari-
ation in the number of microsporophylls comprising each pol-
len cone, which results in pollen cones with an overall shape
ranging from long cylindrical to more globose (even when
only expanded cones are considered). Sewardiodendron laxum
and E. williamsoni have numerous (501) microsporophylls
per pollen cone, as compared with 124 (estimated 3050) in
A. asfaltenis and 1220 in Taiwania. The greater number of
microsporophylls (and thus long, cylindric pollen cones) seems
to be a common feature of Jurassic Cupressaceae. It is not with-
out notice that more recent taxa have fewer microsporophylls per
cone (e.g., Cupressoids often have fewer than 10), possibly
paralleling general reductive trends observed for seed cones.
Evidence for the continued elongation of the pollen cone
bearing axes, similar to Cunninghamia, is seen in A. minuta,
A. asfaltensis, and E. zhouii (Escapa et al. 2008a; Shi et al.
2014). This interpretation is based on clusters of lateral pollen
cones subtended by specialized bracts found on some shoots,
which would have been produced by the apical meristem at the
time of original shoot growth, placing the pollen cone clusters
originally at the end of the shoot and then secondarily appearing
lateral after the shoot resumes elongation. It is important to note
that in all taxa with pollen cone clusters, branchlets with the
clusters are also shed as units without further elongation. Thus,
it may be difcult to condently discern, withoutvery large sam-
ple sizes (and still this would be an assumption based on negative
evidence), whether resumed shoot elongation occurs in fossil
taxa with pollen cone clusters. It therefore remains unknown
whether the resumed shoot elongation is a characteristic of other
CONTRERAS ET AL.ANEWAUSTROHAMIA FROM THE EARLY JURASSIC 863
species of Elatides,Sewardiodendron,andA. acanthobractea.It
is interesting, however, that this appears to be a habit shared by
fossil taxa and extant Cunninghamia but not with extant
Taiwania, which sheds the pollen cone clusters following pollen
release (g. 8N).
Overall, the organization of pollen cones into clusters ap-
pears to be a dening feature, and a plesiomorphic condition,
of early-divergent Cupressaceae (Escapa et al. 2008a; Shi et al.
2014; Herrera et al. 2017; Dong et al. 2018). The few excep-
tions (e.g., the single, terminal pollen cone in Elatides curvifo-
lia; Miller and LaPasha 1984) are not well understood, and it
would be worthwhile to reexamine this character. While both
Taiwania and Cunninghamia share the same basic structure
as the Jurassic representatives, Taiwania is more similar in the
size of its pollen cones clusters. The smaller clusters thus appear
to be the plesiomorphic condition for Cupressaceae. The large
clusters observed in fossil and extant Cunninghamia are thus
far a feature unique to the genus. Conversely, the continued
elongation of the pollen conebearing axis, as in Cunninghamia
but not Taiwania, may be more characteristic of the early fossil
species. Notably, two of the extant lineages most closely related
to Cupressaceae, Cephalotaxus Siebold et Zucc. ex Endl. and
Sciadopitys Siebold et Zucc., also have aggregations of axillary
pollen cones. However, in these taxa, the apical meristem of the
supporting shoot is terminated by a pollen cone (among other
differences), and thus, their pollen cones are considered to form
a compound structure (Schulz et al. 2014).
Foliage. The leaf morphology of members of the Cupres-
saceae was already diverse during the Jurassic. De Laubenfels
(1953) suggested that the ancestral leaf type for all conifers
was tetragonal in cross section with a free, spreading blade that
was falcate in prole (Type Ileaves sensu de Laubenfels). In-
deed, this type of leaf is common among Jurassic and Creta-
ceous Cupressaceae, particularly among the widespread Elatides
species. The Jurassic taxa Sewardiodendron and Austrohamia,
however, have linear, bifacially attened leaves (Type IIleaves
sensu de Laubenfels). Furthermore, numerous species of the
morphogenus Elatocladus (Halle) Harris (equivalent to Type II
leaves) have been described from Argentina and Antarctica from
the Triassic and Jurassic and throughout both the Southern and
the Northern Hemispheres through the Cretaceous (see Bodnar
et al. 2015). In many cases for the Southern Hemisphere record,
the leaves of Elatocladus have been attributed to the Podocar-
paceae, whereas in the Northern Hemisphere, Elatocladus remains
have been mostly associated with the Cupressaceae (Bodnar et al.
2015; Blomenkemper et al. 2018). Recently, Bodnar et al. (2015)
reconstructed a tree from the Middle Triassic Cortaderita For-
mation of Argentina based on co-occurring permineralized wood
(Cupressinoxylon zamunerae Bodnar, Ruiz, Artabe, Morel et
Ganuza) and impressions of branches with leaves (Elatocladus
planus [Feistmantel] Seward), which, on the basis of numerous
wood anatomical and leaf characters, was assigned to Cupressa-
ceae sensu lato. In this case, branches were described to have
dimorphic leaves (scale-like on the penultimate branches and at
the base of ultimate branches but of the Elatocladus type on ulti-
mate branches). This record suggests that at least some of the
E. planus records described from the Southern Hemisphere, as
far back as the Triassic, may belong to Cupressaceae rather than
to Podocarpaceae (Bodnar et al. 2015). Several other leaf forms
have been described from the Jurassic and attributed to Cupres-
saceae in the absence of attached reproductive material, includ-
ing Cupressinocladus Seward, Thuites Newberry, and Cyparis-
sidium Heer (Chaloner and Lorch 1960; Miller 1977), all of
which are essentially scale-like (Type IIIleaves sensu de Lau-
benfels). Despite the lack of reproductive material associated
with some of the foliage remains and the resulting uncertainty
in relationships (e.g., some of these materials are now attrib-
uted to the Cheirolepideaceae; Alvin 1982), it seems that most of
the basic leaf types were probably present in the Cupressaceae
by the end of the Jurassic, although representatives with bifa-
cially attened blades and tetragonal (awl-like) leaves appear to
be the most common, particularly among the more condently
assigned remains.
Much of the variation in general leaf morphology is due to
environmental differences, and for this reason, some authors
have deemphasized the systematic importance of such charac-
ters (e.g., de Laubenfels 1953). These include the orientation
of leaf blades on the shoot, characteristics of the leaf margin,
and even stomatal distributions. Some of these characters are
known to vary within species and even within individual trees.
For example, intraindividual variation in leaf orientation from
helically disposed to planar is commonly observed in living taxa
(e.g., Cunninghamia spp.; Farjon 2005) and can often be recog-
nized in fossil specimens as well (e.g., Miller and LaPasha
1984). This variability can be due to the light environment dur-
ing development, with planar orientations being the result of
low light during shoot development and three-dimensional
orientations being the result of high-light environments (Bro-
dribb and Hill 1997). It can also be due to programmed differ-
ences between vegetative and reproductive shoots, generally in
which reproductive axes bear helically disposed leaves, regard-
less of the disposition of leaves on strictly vegetative regions of
shoots. The latter is likely the case for the originally described
differences in leaf orientation between A. minuta and A. acan-
thobractea (Zhang et al. 2012). The abundant specimens of
A. asfaltensis show this full range of variation across different
shoots. Nonetheless, these characteristics are still useful when
natural variability is characterized and taken into account, as
distinct differences exist between taxa that never show a charac-
teristic (e.g., Taiwania and Elatides spp. never show planar ori-
entation of leaves) versus ones that exhibit it on some shoots
or specic shoot types.
Interestingly, the distinct leaf characteristics of living Cun-
ninghamia and Taiwania are unique compared with the Juras-
sic leaf forms. The distinct leaf morphology of extant Cun-
ninghamia (large lanceolate leaves with serrated edges, wide
stomatal bands with sunken stomata, and three resin canals)
is not seen until the Late Cretaceous (C. taylorii; Serbet et al.
2013). Likewise, the mature foliage of Taiwania is rather unique
for the family and seen only in the extant species and its nearly
identical fossil representatives.
Early Evolution of Cupressaceae
Although unambiguous fossil records of Cupressaceae (i.e.,
including reproductive material) are currently known only from
the Jurassic and more recent periods, other lines of evidence
have long pointed to a Triassic origin for the family (see Bodnar
et al. 2015). The records of A. minuta and A. asfaltensis, with
multiple reproductive and vegetative organs, provide condent
864 INTERNATIONAL JOURNAL OF PLANT SCIENCES
assignment to Cupreassaceae that denitely supports its pres-
ence by the early Jurassic in South America. The biogeograph-
ically disjunct occurrence of A. acanthobractea in China dur-
ing the late Middle Jurassic prompted Zhang et al. (2012) to
hypothesize that Austrohamia migrated from South America
through northern Africa and Europe to East Asia. Mao et al.
(2012) concluded, based on maximum likelihood ancestral area
reconstructions, that the center of origin for the Cupressaceae
was in East Asia during the Triassic and that land dispersal
through North America led to the Southern Hemisphere occur-
rences (Mao et al. 2012). The expanding record of early occur-
rences of Cupressaceae in the Southern Hemisphere (Escapa et al.
2008a; Bodnar et al. 2015; Bodnar and Escapa 2016; this arti-
cle) hint at even greater undiscovered diversity, suggesting that
the apparent paucity of early-diverging cupressaceaeous taxa in
the less well-known Southern Hemisphere is not a true reec-
tion of paleodistributions. This emphasizes that additional
work on Triassic and Jurassic oras will be needed to advance
our understanding of the early biogeography of the family, in
conjunction with a better understanding of the phylogeny of
the group since the relationships among Cunninghamia-like
forms are not clear. Regardless, it is clear that by the middle Ju-
rassic, the family was established in both hemispheres (e.g.,
Harris 1943, 1979; Yao et al. 1998; Zhang et al. 2012; Spencer
et al. 2015). Middle-upper Jurassic collections all over the
world contain abundant cupressaceous remains, particularly
those of the Elatides type, making it apparent that these coni-
fers were an important component of Jurassic and Cretaceous
landscapes worldwide.
The emerging picture of the earliest Cupressaceae is that of a
diverse lineage of cunninghamioid and taiwanioid-like conifers,
adapted to a range of habitats (evidenced by different deposi-
tional settings and various leaf morphologies that are thought
to be adaptive under different environmental conditions/light
regimes). The oldest Jurassic taxa, namely, Austrohamia and
Sewardiodendron, had broader leaves and grew in wet environ-
ments, congruent with physiological studies suggesting that
ancestral (and especially Mesozoic) Cupressaceae were drought
intolerant and depended on moist habitats (Pittermann et al.
2012). All of the conifers associated with the cunninghamioid-
taiwanioid complex had seed cones that were not extensively
lignied or thickened and (if known) pollen cones that were ar-
ranged in small clusters. The seed cone characteristics suggest
that they were not adapted to frequent or intense re regimes,
unlike many of the later diverging sequoioid, cupressoid, and
callitroid lineages.
The evolutionary relationships of the earliest taxa sharing
these similar seed cone and pollen cone morphologies remain
unsatisfactorily understood. The difculty in understanding re-
lationships among fossil and extant Cupressaceae is due in part
to the apparent mosaic character evolution and is compounded
by the incomplete understanding of fossil taxa as whole or-
ganisms and the differential information available from various
modes of preservation. Moreover, throughout the Mesozoic,
the taxodiaceous Cupressaceae likely formed large clades that
were evolving along their own trajectories. Extinction has largely
erased most of this history. For instance, Cunninghamia repre-
sents the earliest-diverging crown lineage for Cupressaceae, but
evaluation of the fossil record suggests that it possesses many de-
rived characteristics from the basal plexus of Jurassic-Cretaceous
cunninghamiods.These derived characteristics become appar-
ent only when the pollen cone and leaf characteristics of extinct
taxa are also considered, as demonstrated from the comparisons
of Austrohamia with other Jurassic and Cretaceous taxa. In the
endeavor to further understand the early evolution of the family,
the development of additional whole-plant concepts for cupres-
saceous taxa throughout the Mesozoic will be particularly valu-
able (e.g., Escapa and Leslie 2017), in conjunction with further
discovery of new organ-based taxa with detailed understand-
ing of anatomical and structural characteristics (Rothwell et al.
2011; Spencer et al. 2015). These will help to generate a more
complete picture of the basalmost characteristics for the family,
which will in turn aid in the search for potential stem taxa be-
tween other living and extinct conifer groups as the broader
evolutionary history of conifers sensu lato is pieced together.
Conclusions
The Early Jurassic A. asfaltensis (~179 Ma) and A. minuta
(~183187 Ma) are the oldest fossil taxa that can be condently
assigned to Cupressaceae sensu lato based on multiple repro-
ductive and vegetative organs. The new whole-plant recon-
struction of A. asfaltensis provides an important new record
of taxodiaceous Cupressaceae for the Southern Hemisphere
and adds to the known diversity of extinct taxa associated with
the cunninghamioid-taiwanioid complex. Assignment of the
new species to Austrohamia adds morphological diversity to
the genus, which was previously known from two morpholog-
ically near-identical species (Escapa et al. 2008a; Zhang et al.
2012; Dong et al. 2018). With three known Jurassic species
and reconstructions from multiple organs, including new records
of wood (Protaxodioxylon patagonicum Bodnar et Escapa;
Bodnar and Escapa 2016), Austrohamia represents the most
well-understood genus of Jurassic Cupressaceae.
Acknowledgments
We thank Mariano Caffa, Pablo Puerta, Laura Nicoli, and
many others for assistance in eld collections; the UC Botanical
Garden and Holly Forbes for assistance in collecting extant ma-
terial; and the University of California and Jepson Herbaria.
This study was supported by the Evolving Earth Foundation
(grant to D. L. Contreras), the National Science Foundation
(Graduate Research Fellowship Grant no. DGE 1106400 to
D. L. Contreras), and the Agencia Nacional de Promoción Cien-
ca y Tecnológica (PICT 12 1224, PI: IE; PICT 1520, PI: RC).
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868 INTERNATIONAL JOURNAL OF PLANT SCIENCES
... Sobre esta base comenzó una nueva etapa en el conocimiento de las floras, enfocada principalmente en reconstrucciones de índole paleobiológico, poniendo énfasis en la descripción de detalle de especies, en base a múltiples órganos, tanto vegetativos como reproductivos, y su asociación para desarrollar conceptos de planta más completos. Así, se reconstruyeron especies de linajes diversos tales como equisetales (Elgorriaga et al. 2015), helechos de las familias Osmundaceae, Dipteridaceae y Marattiaceae , Choo et al. 2016, coníferas de las familias Cupressaceae, Araucariaceae y Cheirolepidiaceae (Escapa et al. 2008b, Escapa 2009, Bodnar y Escapa 2016, Escapa y Leslie 2017, Contreras et al. 2019), y pteridospermas de las familias Caytoniaceae y Peltaspermaceae (Elgorriaga et al. 2019a,b), constituyendo un núcleo de diversidad que se completa con otros elementos que aún no han sido estudiados en detalle, como las Bennettitales o especies de afiliación sistemática incierta (e.g. Archangelskya furcata, Sphenopteris nordenskjöldii). ...
... 5F,J-I. Cupressaceae), recientemente descripta en base a más de 200 especímenes que presentan numerosos conos polínicos y ovulíferos, preservados en conexión orgánica con ramas y hojas (Contreras et al. 2019). Esta nueva especie coincide morfológicamente con lo mencionado originalmente por Frenguelli (1949b) como Palissya, y ubicado posteriormente en la familia Cupressaceae por Escapa (2009), dentro del género Elatides. ...
... El hecho que Frenguelli determinara la presencia de dos especies de Palissya, posiblemente responde a un sesgo en la colección original. Los nuevos especímenes muestran que los dos tipos descriptos corresponden a dos estadíos en la ontogenia del cono ovulífero, creciendo sobre la misma planta (Contreras et al. 2019). La reconstrucción de Austrohamia asfaltensis representa la tercera en este género relacionado con las cupresáceas más basales, sumándose a Austrohamia minuta (Jurásico inferior, Argentina) y A. acanthobractea (Jurásico medio, China), delimitando un linaje con amplia distribución durante el Jurásico. ...
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En la cuenca de Cañadón Asfalto se reconocen cuatro formaciones depositadas durante el Jurásico: Las Leoneras y Lonco Trapial (Sinemuriano - Pliensbachiano), Cañadón Asfalto (Toarciano - Aaleniano?) y Cañadón Calcáreo (Oxfordiano - Kimmeridgiano). Todas ellas preservan restos megaflorísticos a modo de impresiones, compresiones y permineralizaciones, como así también una diversa microflora. Las megafloras se componen de especies pertenecientes a diversos grupos, incluyendo Equisetales, helechos de las familias Dipteridaceae, Marattiaceae y Osmundaceae, coníferas de las familias Araucariacaeae, Cupressaceae y Cheirolepidiaceae, bennettitales y pteridospermas de las familias Caytoniaceae y Peltaspermaceae, y otras especies de afinidad sistemática incierta. El hallazgo de nuevas localidades y la colección extensiva de especímenes permitieron la reconstrucción de un número importante de especies sobre la base de órganos vegetativos y reproductivos; un recurso significativo para comprender la paleobiología de cada especie y de las comunidades vegetales jurásicas de Gondwana. En base a comparaciones de las especies reconstruidas con sus parientes vivientes más cercanos, y en conjunto con el estudio detallado de caracteres de relevancia para reconstrucciones paleoclimáticas y paleoecológicas (e.g., disposición y tipos de estomas), se discuten y establecen tres períodos dentro del Jurásico representados por las reconstrucciones del bioma reinante en cada una de las formaciones. En el Jurásico inferior bajo, representado por las formaciones Las Leoneras (y equivalentes laterales) y Lonco Trapial, se habrían desarrollado climas con altas temperaturas y niveles de humedad. Luego, hacia la parte más alta del Jurásico inferior, representado por la Formación Cañadón Asfalto, el clima habría sido fuertemente estacional y templado cálido con inviernos húmedos. Finalmente, hacia el Jurásico superior, representado por la Formación Cañadón Calcáreo, las condiciones climáticas se habrían asemejado a las del Jurásico inferior bajo, con altas temperaturas y niveles de humedad.
... To infer the evolutionary relationships of the described conifers, phylogenetic analyses were conducted within maximum parsimony and Bayesian frameworks using the morphological matrix of Herrera et al. (2017), with the addition of more recently described whole-plant taxa Austrohamia asfaltensis D.L. Contreras, I.H. Escapa, R.C. Iribarren et Cúneo (Contreras et al. 2019) and Austrohamia acanthobractea Zhang, D'Rozario, Wang, Li et Yao Dong et al. 2018), and taxa known from ovulate cones, Mukawastrobus satoi Stockey, Nishida et Rothwell (Stockey et al. 2020a) and Comoxostrobus rossii Stockey, Rothwell et Atkinson (Stockey et al. 2020b). TNT version 1.5 (Goloboff and Catalano 2016) was used for the parsimony analyses, with all characters equally weighted and character states unordered. ...
... Grey boxes encompass the temporal range for taxa assigned to the modern genera Cunninghamia and Taiwania. Taxon references: Atkinson et al. 2014aAtkinson et al. , 2014bBarale et al. 2002;Bell 1956;Boyd 1992;Contreras et al. 2019;Dai et al. 2011;Dillhoff et al. 2005;Dong et al. 2018;Escapa et al. 2008;Harris 1943Harris , 1953Harris , 1979Heer 1874Heer , 1876Herrera et al. 2017;Jin et al. 2018;Klymiuk et al. 2015;Krassilov 1967;Kva cek et al. 2018;Lepage 2009;Miller 1975Miller , 1990Miller and Crabtree 1989;Miller and LaPasha 1984;Nishida et al. 1992;Ohana and Kimura 1995;Rothwell et al. 2011;Saiki and Kimura 1993;Samylina 1988;Serbet et al. 2013;Shi et al. 2014;Si 1963;Spencer et al. 2015;Stockey et al. 2020aStockey et al. , 2020bStopes and Fujii 1910;Schweitzer and Kirchner 1996;Tan and Zhu 1982;Walther 1989;Wan 1996;Wang 1984;Wang et al. 2016;Yao et al. 1998;Zhang and Xiong 1983;Zhang et al. 1980Zhang et al. , 2012Zheng and Zhang 1982;Zhou 1987Zhou , 2009 centripetal margins of the wood represent metaxylem with helical and (or) scalariform wall thickenings. The cortex is broad and made up of thick-walled parenchyma and conspicuous resin canals (Fig. 5A) that branch to produce the central canal in each bract-scale complex (Fig. 4D). ...
... Systematic studies using nucleotide sequence characters have designated the above extant genera as comprising the subfamilies, Cunninghamioideae, Taiwanioideae, and Athrotaxoideae, which form the three basal lineages of the taxodiaceous grade of Cupressaceae with living species, respectively (Gadek et al. 2000;Kusumi et al. 2000;Mao et al. 2012). The fossil record of conifers associated with these lineages is extensive, with representatives appearing in the Early Jurassic (Escapa et al. 2008) in Patagonia and across both hemispheres by the Middle Jurassic (see Herrera et al. 2017 andContreras et al. 2019 for recent reviews; Fig. 8). Here, Ohanastrobus and Nishidastrobus are considered to be most comparable to the Cunninghamioideae based on the presence of numerous foliate bract-scale complexes with free ovuliferous scale tips, inverted winged seeds borne adaxially on bract-scale complexes, and their phylogenetic positions (Fig. 7). ...
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Conifers of the taxodiaceous grade of Cupressaceae were more diverse and widespread during the Mesozoic than they are today. The earliest diverging subfamily, Cunninghamioideae, only includes a single extant genus, but has at least 10 fossil genera. Here, two additional cunninghamioid genera are characterized on the basis of permineralized seed cones from the Upper Cretaceous of Hokkaido, Japan. These conifers display seed cone characters typical of cunninghamioids; however, they have a mosaic of characters that are not seen in any reported conifer of Cupressaceae. They are, therefore, designated as two new extinct species: Ohanastrobus hokkaidoensis gen. et sp. nov. and Nishidastrobus japonicum gen. et sp. nov. These newly reported conifers expand the taxonomic and morphological diversity of cunninghamioids. The stratigraphic and paleobiogeographic records of cunninghamioids and other fossil Cupressaceae with foliate seed cones indicate they peak in diversity during the Cretaceous. The living genera Taiwania and Cunninghamia appear during the Albian and Campanian, respectively, and maintain a nearly continuous fossil record through to today, while nearly all other extinct genera of Cupressaceae with foliate cones disappear by the close of the Campanian. As more ancient cunninghamioids are recovered, our understanding of macroevolutionary patterns of this once diverse lineage will be further elucidated.
... Some authors argue that the extant conifer lineage of Podocarpaceae originated before the end-Permian mass extinction (e.g., Blomenkemper et al. 2018). The major radiation started during the Triassic, with the origination of several families such as Araucariaceae, Taxaceae, Taxodiaceae, Cupressaceae, and Pinaceae (e.g., Miller 1982;Archibold 1995;Farjon 2005Farjon , 2008Rothwell et al. 2005Rothwell et al. , 2012Stockey et al. 2005;Anderson et al. 2007;Axsmith et al. 2008;Eckenwalder 2009;Escapa 2009;Hedges and Kumar 2009;Williams 2009;Escapa et al. 2010Escapa et al. , 2011Escapa and Catalano 2013;Contreras et al. 2019). ...
... The wood Brachyoxylon currumilii Bodnar, Escapa, Cúneo & Gnaedinger from the Cañadón Asfalto Formation (late Early-early Middle Jurassic), Chubut Province, Argentina, was tentatively referred to the Hirmeriellaceae (Bodnar et al. 2013). However, the Cañadón Asfalto Formation has not yet yielded unquestionable Hirmeriellaceae reproductive organs, except pollen, and yielded however the wood Protaxodioxylon patagonicum Bodnar & Escapa and Cupressaceae remains (Contreras et al. 2019). ...
Article
The Hirmeriellaceae are an extinct family of Mesozoic conifers. Their foliage has been described in the genera Brachyphyllum , Frenelopsis , Pseudofrenelopsis , etc., while their pollen corresponds to the genus Classopollis , the male cones to e.g. Classostrobus or Tomaxellia and the female scales were named Hirmeriella and Paraucaria , for example. Reproductive structures are necessary for a definite identification of the family. Such fossils are rarely found in connection with mature secondary xylem. As a result, very little is known about the wood anatomy of the Hirmeriellaceae. This work reviews available evidences, either from connections between wood and reproductive structures typical for the Hirmeriellaceae or from associations of such fossils within Mesozoic rocks. Connection cases are rare