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Paleogene records of birds in the Eastern margin of the Pacific Ocean have increased in recent years, being almost exclusively restricted to fossil Sphenisciformes (penguins). New avian remains (Ornithurae, Neornithes) from Middle-to-Late Eocene levels of the Estratos de Algarrobo unit, in Algarrobo, central Chile, are disclosed in the present work. These new finds are significant in representing the first non-spheniscid bird remains of Middle to Late Eocene age, recovered in mid-latitudes of the eastern Pacific and probably belonging to a procelarid. It complements the regional record of Eocene birds, previously known only at high-latitudes such as Seymour Island (Antarctica) and Magallanes (Chile), and low-latitude locations in Peru. RESUMEN. Primeros restos de aves del Eoceno de Algarrobo, Chile central. Los registros de aves paleógenas en el margen oriental del Océano Pacífico se han incrementado en los últimos años, estando casi exclusivamente restringidos a Sphenisciformes fósiles (pingüinos). Nuevos fósiles avianos (Ornithurae, Neornithes) provenientes de niveles del Eoceno Medio a Tardío de los Estratos de Algarrobo, en Algarrobo, Chile central, son dados a conocer en el presente trabajo. Estos nuevos hallazgos son significativos en representar los primeros restos de aves no-spheníscidos de edad Eoceno Medio a Tardío, recuperadas en latitudes intermedias del Pacífico oriental y probablemente pertenezcan a un procelárido. Este hallazgo complementa el registro regional del grupo durante el Eoceno, anteriormente conocido en localidades de altas latitudes como isla Seymour (Antártica) y Magallanes (Chile), y localidades de bajas latitudes en Perú.
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Andean Geology 39 (3): 548-557. September, 2012 Andean Geology
formerly Revista Geológica de Chile
First bird remains from the Eocene of Algarrobo, central Chile
Roberto E. Yury-Yáñez1, Rodrigo A. Otero2, Sergio Soto-Acuña3, Mario E. Suárez4,
David Rubilar-Rogers2, Michel Sallaberry1*
1 Laboratorio de Zoología de Vertebrados, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile. Las
Palmeras 3425, Ñuñoa, Santiago, Chile.;
2 Área Paleontología, Museo Nacional de Historia Natural. Casilla 787, Santiago.;
Laboratorio de Ontogenia y Filogenia, Departamento de Biología, Facultad de Ciencias, Universidad de Chile. Las Palmeras 3425,
Santiago, Chile.
4 Museo Paleontológico de Caldera. Av. Wheelwright 001, Caldera, Atacama, Chile.
* Corresponding author.
ABSTRACT. Paleogene records of birds in the Eastern margin of the Pacific Ocean have increased in recent years,
being almost exclusively restricted to fossil Sphenisciformes (penguins). New avian remains (Ornithurae, Neornithes)
from Middle-to-Late Eocene levels of the Estratos de Algarrobo unit, in Algarrobo, central Chile, are disclosed in the
present work. These new finds are significant in representing the first non-spheniscid bird remains of Middle to Late
Eocene age, recovered in mid-latitudes of the eastern Pacific and probably belonging to a procelarid. It complements
the regional record of Eocene birds, previously known only at high-latitudes such as Seymour Island (Antarctica) and
Magallanes (Chile), and low-latitude locations in Peru.
Keywords: Birds, Eocene, Biogeography, Algarrobo, Chile.
RESUMEN. Primeros restos de aves del Eoceno de Algarrobo, Chile central. Los registros de aves paleógenas en el
margen oriental del Océano Pacífico se han incrementado en los últimos años, estando casi exclusivamente restringidos
a Sphenisciformes fósiles (pingüinos). Nuevos fósiles avianos (Ornithurae, Neornithes) provenientes de niveles del
Eoceno Medio a Tardío de los Estratos de Algarrobo, en Algarrobo, Chile central, son dados a conocer en el presente
trabajo. Estos nuevos hallazgos son significativos en representar los primeros restos de aves no-spheníscidos de edad
Eoceno Medio a Tardío, recuperadas en latitudes intermedias del Pacífico oriental y probablemente pertenezcan a un
procelárido. Este hallazgo complementa el registro regional del grupo durante el Eoceno, anteriormente conocido en
localidades de altas latitudes como isla Seymour (Antártica) y Magallanes (Chile), y localidades de bajas latitudes en Perú.
Palabras clave: Aves, Eoceno, Biogeografía, Algarrobo, Chile.
doi: 10.5027/andgeoV39n3-a10
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1. Introduction
The fossil record of birds from Chile is especially
well-represented during the Neogene, with finds
recovered from levels of the La Portada Forma-
tion (Ferraris and Di Biase, 1978), Bahía Inglesa
Formation (Rojo, 1985 emmended by Marquardt
et al., 2000) and Coquimbo Formation (Moscoso et
al., 1982), in the northern area of the country (e.g.,
Walsh and Hume, 2001; Emslie and Guerra Correa,
2003; Acosta Hospitaleche et al., 2006; Walsh and
Suárez, 2006; Sallaberry et al., 2007; Mayr and
Rubilar-Rogers, 2010), being mostly comprised by
marine taxa (Chávez, 2007). The fossil record of
continental birds is restricted to Meganhiga chilensis,
Alvarenga (1995) from Miocene levels correlated
with Curamallín Formation (Niemeyer and Muñoz,
1983) in Lonquimay, south-central Chile and an
isolated tarsometatarsus of Milvago sp. from La
Portada Formation, Antofagasta (Emslie and Guerra
Correa, 2003).
To date, the Paleogene record of birds from the
eastern margin of South America is known from
localities in the southernmost part of the continent,
and low-latitude localities, some of them near the
Equator. The southernmost record of fossil birds in
South America comes from the Leticia Formation (late
Middle Eocene), Tierra del Fuego, Argentina, where
an associated pelvic girdle and limb were recovered
and assigned to Pansphenisciformes indet. (sensu
Clarke et al., 2003). From the San Julián Formation
(?Late Eocene-?Early Oligocene), southernmost
Argentina, came two stem penguin belonging to
extinct species: Arthrodytes andrewsi (Ameghino,
1901) and Paraptenodytes robustus (Ameghino,
1895). Their systematic position has been revised
by Acosta Hospitaleche (2005) confirming their
stem position. Southern discoveries also include
indeterminate penguin remains (Sphenisciformes),
represented at least by two morphotypes of different
size, also large-sized penguins of the genus Pal-
aeeudyptes, and a fragmentary tibiotarsus referred
to a probable indeterminate Ardeidae, all recovered
from three units of middle to late Eocene exposed in
Magallanes, southernmost Chile (Sallaberry et al.,
2010). The low-latitude records are represented by
endemic species such as Perudyptes devriesi Clarke
et al., 2007, from middle Eocene levels of the Paracas
Formation, Peru, and Icadyptes salasi Clarke et al.,
2007, recovered from Upper Eocene levels of the
Otuma Formation, Peru. A third endemic species,
Inkayacu paracasensis Clarke et al., 2010, was
described from Late Eocene levels of the Yumaque
Point, in the Paracas reserve, Peru. More recently
closer phylogenetic affinities between Peruvian (In-
kayacu) and Antarctic Eocene penguins have been
suggested, being considered probably congeneric
(Jadwiszczak, 2011).
No further Eocene fossil birds are known from
the Eastern South Pacific. Here we describe new
material from central Chile representing the first
non-penguin remains of the Middle to Late Eocene,
from intermediate latitude between the Magallanes
Region and Perú. Besides the fossil heron from
Magallanes, all the Eocene record of birds from the
western coast of South America are comprised by
penguins (Sphenisciformes).
The materials here described are hosted at the
Área de Paleontología, Museo Nacional de Historia
Natural, Santiago de Chile under the acronym SGO.PV.
2. Locality and Geological Setting
The studied specimens were collected at the
coastal town of Algarrobo (33°22’S; 71°40’W) in
central Chile, placed aproximately 120 km W from
Santiago (Fig. 1). In this locality, a discrete sequence
of sedimentary sequence rocks is exposed along the
coastal line, belonging to two different units:
2.1. Estratos de la Quebrada Municipalidad
(Gana et al., 1996).
Discrete succession of transgressive, marine beds
that extends about 40 m along the coastal shore. It is
mainly conformed by sandstones, with some frequently
glauconitic levels and fine conglomerate lenses
(Fig. 1). This unit was assigned to the Maastrichtian
based on representative fossils invertebrates such us
Cardium (Bucardium) acuticostatum (D’Orbigny),
Pacitrigonia hanetiana (D’Orbigny), Grossouvreites
sp. and Pachydiscus sp. (Tavera, 1980), and a radio-
isotopic date obtained from bivalvian shells (Suárez
and Marquardt, 2003) that indicates 69±01 Ma. The
fossil assemblage is also comprised by abundant
vertebrates including a few actinopterygian fishes
(e.g., aspidorhynchids; Brito and Suárez, 2003), a
great diversity of elasmobranchs (e.g., Odontas-
pididae, Palaeospinacidae, Squatinidae, Squalidae,
Echinorhinidae, Schlerorhynchidae, Dasyatidae,
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550 First bird remains From the eocene oF algarrobo, central chile
FIG. 1. 1. Schematic map of most relevant Eocene units with fossil bird remains along Chile and South America. A. Algarrobo, Val-
paraíso Region, marked with a square, indicating the locality of provenance of the studied specimens. Estratos de Algarrobo,
Middle to Late Eocene; B. Sierra Baguales. Río Baguales Formation, Middle to Late Eocene; C. Sierra Dorotea. Río Turbio
Formation, Middle to Late Eocene; D. Punta Arenas. Loreto Formation, Middle to Late Eocene. Other Eocene localities in
South America with fossil birds; E. Ica, Perú. Otuma and Paracas formations, Middle to Late Eocene; F. Tierra del Fuego,
Argentina. Leticia Formation, Middle Eocene. 2. Stratigraphic scheme of the studied section exposed at Algarrobo, based on
Tavera (1980) and present field observations, including the hosting level of the studied material.
Yuri-Yañez337.indd 550 14-09-2012 10:02:06
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Callorhynchidae and Chimaeridae; Suárez et al.,
2003; Suárez and Cappetta, 2004; Otero and Suárez,
2009) and marine reptiles (e.g., elasmosaurid ple-
siosaurs, cf. dermochelyid turtles and indeterminate
mosasaurs; Otero et al., in 2012).
Fossil invertebrates are also abundant (Philippi,
1887; Brüggen, 1915). Finally, scarce carbonized
wood remains can be often observed.
2.2. Estratos de Algarrobo (Gana et al., 1996).
This succession is conformed by sandstones of
variable grain size and hardness, very fossiliferous,
with abundant concretionary nodules in different
levels. It is exposed for approximately 150 m along
the coast (95 m of thickness) and overlies the Estratos
de la Quebrada Municipalidad through an erosive
discordance (Fig. 1). The roof of the unit is constrained
by a granitic basement through an inferred fault. This
unit was assigned to the Middle to Late Eocene based
on fossil invertebrates with good chronostratigraphic
resolution (Brüggen 1915; Tavera, 1980). Addition-
ally, endemic fossil crustaceans have been described
from this unit (Schweitzer et al., 2006).
The fossil specimens here studied were collected
from this unit, associated to dental plates of rays
(Myliobatis sp.), being later prepared at the Museo
Nacional de Historia Natural, Santiago, during 2009.
3. Systematic Paleontology
Aves Linnaeus, 1758
Ornithurae Haeckel, 1866
Neornithes Gadow, 1893
Neornithes indet.
Fig. 2
Material: SGO.PV 1024a: Distal fragment of right
femur, SGO.PV.1024b: proximal end of right femur.
Collected by one of the authors (MES).
Horizon and age: Estratos de Algarrobo (Gana et
al., 1996), Middle to Late Eocene.
Description: The anatomical nomenclature follows
Baumel and Witmer (1993). The distal portion (SGO.
PV.1024a) preserves both condyli, being eroded
in their medial and lateral surfaces. The condylus
medialis is smaller than the condylus lateralis and
it is projected medially. The condylus lateralis
extends distally beyond the condylus medialis.
In lateral view the trochlea fibularis have a more
lateral position than the condylus lateralis. In the
caudal view, the impressio ligamentaris cruciati
cranialis and the impressio ligamentaris cruciati
caudalis are both visible. The fossa poplitea is
deep and well defined by a distal ridge. The crista
tibiofibularis is conspicuous but poorly preserved.
The tuberculum musculi gastrocnemialis lateralis
appears in a lateral position. The crista supracon-
dylaris medialis is present but eroded. In caudal
view, a broad sulcus patellaris and a deep sulcus
intercondylaris are present, but the impression
ligamentaris collateralis lateralis and the fovea
tendineus of the musculi tibialis cranialis are lost due
to erosion. The preserved portion of the diaphysis
has a subcircular cross section. The measurements
of the distal fragment are: maximum preserved
proximal-distal length from the condylus lateralis
18.92 mm, width of condylus lateralis 4.86 mm,
cranio caudal width of condylus lateralis 10.64 mm,
cranio caudal width of the sulcus intercondylaris
6.36 mm, width of condylus medialis 4.89 mm,
cranio caudal width of condylus lateralis 8.85 mm,
cranio caudal width of the diaphysis 5.49 mm,
width of sulcus patellaris 4.58 mm.
FIG. 2. SGO.PV 1024; Unassociated proximal and distal fragments
of right femur A. cranial view of proximal end; B. caudal
view of proximal end; C. caudal view of distal end; D.
cranial view of distal end. Scale bar =10 mm.
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552 First bird remains From the eocene oF algarrobo, central chile
The proximal fragment (SGO.PV.1024b) is
strongly eroded in the most proximal segment. In
cranial aspect, the crista trochanteris is incomplete
and the surfaces of the facies articularis antitrochan-
terica are eroded, but extended craniocaudally. The
fossa trochanteris, facies articularis acetabularis,
and trochanter femoris cannot be appreciated due
to preservation. The impression musculi obturato-
riae is present but eroded. Caput femoris is well
developed while the fovea ligamentaris capitis is
poorly preserved (Fig. 3). The measurements of
the proximal fragment are maximum preserved
proximal-distal length 18.92 mm, cranio caudal width
of the diaphysis 5.60 mm, proximal width from the
caput femoris to the crista trochanteris 13.62 mm,
cranio caudal width of the caput femoris 5.77 mm,
proximal cranio caudal width above facies articularis
antitrochanterica 6.78 mm.
4. Discussion
In the distal fragment, the presence of the impres-
sio ansae musculi fibularis (Hutchinson, 2001) as
well as conspicuous fossa poplitea (Chiappe, 1996),
are diagnostic in the Ornithothoraces. On the other
hand, the sulcus intercondylaris with a deep proximal
depression (sulcus patellaris) is characteristic of the
clade Ornithurae (Hesperornithiformes+Ichtyorniti
formes and Neornithes) (Chiappe, 1996).
Despite the fragmentary condition of SGO.PV
1024, the presence of traits such as lateral crista
trochanteris confirms its assignment to Ornithurae
(Chiappe, 1995). However, the facies articularis
antitrochanterica extended in cranio-caudal sense,
as observed in the studied specimen, is a probable
synapomorphy of Neornithes (Hope, 2002). Although
the crista trochanteris is eroded, in SGO.PV 1024 it
preserves its proximal portion, allowing us to distin-
guish it from some birds such as ‘Pelecaniformes’
which lack an elevation of the crista trochanteris
(Hope, 2002). The shape of the cross section, the
preserved diaphysis in SGO.PV 1024 allows us
to discard affinities with Gaviiformes, which have
well-defined borders and a laterally compressed
femur (Baumel and Witmer, 1993). On the other
hand, Sphenisciformes have a femur with a flattened
lateral side in proximal portion, without convexity,
unlike SGO.PV 1024, discarding that the fossil could
represent a penguin.
The lack of pneumatic foramen in craniolateral
side of the proximal end of femur is considered a
plesiomorphy in several clades within Neornithes
(Hutchinson, 2001; Mayr and Clarke, 2003). An
apomorphic condition is independently founded in
Cracidae, Phasianidae, Anhimidae, Phoenicopteridae,
Ciconiidae, Otididae from the ‘land birds clade’ or
Node F sensu Hackett et al. (2008) (Mayr and Clarke,
2003), supporting the exclusion of SGO.PV 1024
from these derivate clades of Neornithes.
Based on general proportions and morphol-
ogy, the specimens described here resemble some
groups of aquatic birds. Morphologically, SGO.PV
1024a and SGO.PV 1024b have similar femora to
Procellariiformes and ‘Ciconiiformes’, these birds
comprises the Node H the ‘water birds clade’ sensu
Hackett et al. (2008) a monophyletic unit of aquatic
birds recovered in several phylogenetic analysis
(Mayr, 2011), but also the similarity of SGO.PV
FIG. 3. Anatomical nomenclature according to Baumel and
Witmer (1993). cf: caput femoris; cl: condylus lateralis;
cm: condylus medialis; cscm: crista supracondylaris
medialis; ct: crista trochanteris; ctf: crista tibiofibularis;
el: epicondylus lateralis; em: epicondylus medialis; faat:
facies articularis antitrochanterica; flc: fovea ligamen-
taris capitis; fp: fossa poplitea; iami: impression ansae
musculi iliofibularis; ilccd: impression ligamentaris
cruciati caudalis; ilccn: impression ligamentaris cruciati
cranialis; imo: impression musculi obturatoriae; lic: linea
intermuscularis cranialis; si: sulcus intercondylaris. sp:
sulcus patellaris; tf: trochea fibularis; tmgl: tuberculum
musculi gastrocnemialis lateralis. Scale bar =10 mm.
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Yury-Yáñez et al. / Andean Geology 39 (3): 548-557, 2012
1024 with Podicipediformes and Charadriiformes
do not allow to nested unequivocally within the
‘water birds clade’ sensu Hackett et al. (2008). We
prefer to assign both specimens to a more inclusive
taxonomical level due to the absence of unambiguous
synapomorphies. Nevertheless, we attempt to associ-
ate with high probabilities, SGO.PV 1024 specimen
with a marine bird such as a small procelarid. Figure
4 shows that the lack of a strong ridge in the caput
femoris is shared with all procelarid birds used for
comparison (Daption capense, Fulmarus glacialis,
Pelecanoides garnotti, and Pachyptila belcheri) as
well as the high of the most proximal portion of the
bone, supporting the temptative determination as a
procelarid bird.
Fossil vertebrates are not frequent in the Eocene
outcrops at Algarrobo, and to date, they are only
represented by disarticulated and fragmentary ma-
terials. The presence of bird remains is an extremely
rare finding. It is possible that the two fragments
of femur SGO.PV 1024 could represent a unique
individual, considering the very low frequence of
vertebrate remains in the hosting beds. Moreover,
the proximity of the finding of the fragment in the
field, plus the morphometric comparison of the distal
and proximal ends, particularly the similar cranio
caudal width of the diaphysis, strongly suggest that
they would belong to the same individual.
Bird bones in Algarrobo have an special paleo-
biogeographic relevance. It is the first record of this
kind in Middle-Late Eocene levels of central Chile.
This locality is important because its intermediate
location between the Magallanes Region (Sallaberry
et al., 2010), Tierra del Fuego (Clarke et al., 2003),
Antarctica (Myrcha et al., 2002; Jadwiszczak, 2006;
Tambussi and Acosta Hospitaleche, 2007) and those
from Peru during the same time interval (Acosta
Hospitaleche and Stucchi, 2005; Clarke et al., 2007;
Clarke et al., 2010). Eocene record of birds from
southernmost South America and its Pacific coast is
comprised almost exclusively by Sphenisciformes
(Clarke et al., 2003; Acosta Hospitaleche and Stucchi,
2005; Clarke et al., 2007; Clarke et al., 2010; Salla-
berry et al., 2010), while the specimens here studied
are assignable to a different order of Neornithes.
Because we are here dealing with isolated bones, it
is preferred to avoid risky taxonomic assignments,
employing a conservative criteria (see Ksepka and
Cracraft, 2008); nevertheless, it is important to recall
that SGO.PV 1024 would represent an aquatic bird.
Biogeographically, the opening of the Drake
Passage and the Tasman Rise diminished the main
seaway that crossed from eastern Australia, through
western Antarctica and into southern South America
(Lawver and Gahagan, 2003). This seaway was the
main factor to keep the ecological affinities of marine
vertebrate assemblages along different localities of
the Weddellian Biogeographic Province (Zinsmeister,
1979). Endemic assemblages seem to be restricted to
shallower waters, suggesting that these occurred as
a consequence of local biogeographic barriers. The
establishment of the Antarctic circumpolar current
during the Late Eocene probably as a consequence of
the Drake Passage nearly 41 Ma (Scher and Martin,
2006), and the later beginning of the Humboldt
Current during the Miocene, provided new and more
stable environmental conditions that favoured closer
ecologic affinities between marine vertebrates along
the Pacific in lower latitudes. This suggests a partial
hypothesis of why spheniscid species in Chile and
Perú had closer affinities during the Neogene rather
than during the Paleogene, being represented by
several common species, but retaining the presence
of the circumpolar, extant genus Pygoscelis in
northern Chile as a remarkable difference (Acosta
Hospitaleche et al., 2006; Walsh and Suárez, 2006;
Sallaberry et al., 2008). This record could probably
indicate that a biogeographical barrier existed during
the Eocene in the Pacific coast of South America,
suggesting that Eocene penguins from Peru have a
vicariant origin.
Penguins are often the most frequent birds in
avian fossil assemblages when they are present (Cruz,
2007). In the case of the studied specimens, the pres-
ence of the fragmentary bird bones is also relevant
for the local record, since vertebrate remains in the
Estratos de Algarrobo are very scarce, and to date,
only represented by dental plates of rays (Suárez and
Marquardt, 2003) and isolated fish remains (Tavera,
1980). On the other hand, invertebrate fossils from
the same unit are very abundant and diverse, being
mainly represented by bivalves, gastropods, echino-
derms and nautilids (Brüggen, 1915; Tavera, 1980),
less frequently by endemic decapods, ichnofossils
referred to Ophiomorpha sp. and Thalassinoides sp.
(Schweitzer et al., 2006), and relatively abundant
wood remains, among others. This fossil assemblage
suggest sub-tidal, shallow marine conditions for the
deposit, while the presence of fragmentary wood
remains indicates a possible deltaic environment,
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554 First bird remains From the eocene oF algarrobo, central chile
FIG. 4. Comparison between the studied remains and several femora of extant aquatics birds: A1-A4. SGO.PV 1024 Neornithes
indet; B1-B4. Cape Petrel, Daption capense; C1-C4. Northern Fulmar, Fulmarus glacialis; D1-D4. Peruvian Diving-petrel,
Pelecanoides garnotti; E1-E4. Slender-billed Prion, Pachyptila belcheri; F1-F4. Franklin’s Gull, Larus pipixcan; G1-G4.
Elegant Tern, Sterna elegans; H1-H4. Guanay Cormorant, Phalacrocorax bougainvillii; I1-I4. Humboldt penguin, Spheniscus
humboldti. Proximal portion of femora in cranial (A1, B1, C1, D1, E1, F1, G1, H1, I1) and caudal view (A2, B2, C2, D2, E2,
F2, G2, H2, I2). Distal portion of femora in cranial (A3, B3, C3, D3, E3, F3, G3, H3, I3) and caudal view (A4, B4, C4, D4,
E4, F4, G4, H4, I4). Scale bar = 20 mm.
Yuri-Yañez337.indd 554 14-09-2012 10:02:12
Yury-Yáñez et al. / Andean Geology 39 (3): 548-557, 2012
as previously proposed by Schweitzer et al. (2006).
This can explain the absence of articulated or more
complete vertebrate remains, and the mixed occur-
rence of intertidal fauna with open sea organisms
such as nautiloids. Similar environmental conditions
including marine fauna and indicators of proximity
to the coast are also observed in all Eocene outcrops
at Magallanes Region. Bird remains occur together
with elasmobranch teeth and abundant invertebrates,
mostly bivalves with several common genera present
both in Magallanes and Algarrobo (Tavera, 1946).
Also, as pointed out by Sallaberry et al. (2010), there
is a certain level of correlation between Estratos de
Algarrobo and the Eocene units in Magallanes and
Vicecomodoro Marambio Island (Seymour Island,
The present find verifies the need of more field
work at the Estratos de Algarrobo, that could help to
establish paleoecologic connections (or differences)
between the northernmost Eocene outcrops of the
Weddellian Biogeographic Province and low-latitude
localities in Peru, helping to understand the possible
northern limits of the mentioned Province and the
impact of the opening of the Drake Passage in the
local faunas.
R.E. Yury-Yáñez, R.A. Otero and D. Rubilar-Rogers
are supported by the Antarctic Ring Bicentenary Project
(Proyecto Bicentenario de Ciencia y Tecnología Anillo
Antártico, PBCT-ARTG-04, Conicyt, Chile), and the
current project ACT-105 Conicyt-Chile, both directed
by Dr. T. Torres. All extant birds were reviewed from
the Osteological Collection of the Vertebrate Zoology
Laboratory from the Facultad de Ciencias-Universidad de
Chile. M.E. Suárez and R.A. Otero are authorized by the
Consejo de Monumentos Nacionales (National Council
of Monuments) on March 2006, point 172, for collecting
samples from the studied locality. Also R.E. Yury-Yáñez
is granted with a Conicyt scolarship for Master’s studies
in Chile (Programa de Formación de Capital Humano
Acosta Hospitaleche, C. 2005. Systematic revision of
Arhrodytes Ameghino, 1905 (Aves, Spheniscidae)
and its assignment to the Paraptenodytinae. Neues
Jahrbuch für Geologie und Paläontologie, Monatshefte
7: 404-414.
Acosta Hospitaleche, C.; Stucchi, M. 2005. Nuevos restos
terciarios de Spheniscidae (Aves, Sphenisciformes)
procedentes de la costa del Perú. Revista Española
de Paleontología 20: 1-5.
Acosta Hospitaleche, C.; Chávez, M.; Fritis, O. 2006.
Pingüinos fósiles (Pygoscelis calderensis nov. sp.) en
la Formación Bahía Inglesa (Mioceno Medio- Plio-
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... Although not as complete as Vegavis, some materials overlap with the latter and lead Agnolín et al. (2017) to conclude that they were closely related. Furthermore, with the addition of the Chilean Neogaeornis wetzeli (Lambrecht, 1929), Australornis lovei (Mayr and Scofield, 2014) from New Zealand, and some fragmentary isolated material from the late Cretaceous and Paleogene of Antarctica (Case et al., 2006;Ksepka and Cracraft, 2008;Yury-Yáñez et al., 2012;Acosta Hospitaleche and Gelfo, 2015), Agnolín et al. (2017) established Vegaviidae as an austral clade of basal Anseriformes that survived the K/Pg boundary. More recently, McLachlan et al. (2017) described Maaqwi cascadensis from the Northumberland Fm. (latest Campanian), Canada, and considered this taxon as a Northern Hemisphere representative of Vegaviidae. ...
Vegavis iaai is without any doubt the most complete and well-known Mesozoic bird from Antarctica. In spite of being known by several specimens, its highly specialized postcranial anatomy has obscured the recognition of its phylogenetic affinities. Skull material from Vegavis is scarce, and the lower jaw is known by a relatively well-preserved articular region of a partially articulated specimen (MACN-PV 19.748). The aim of the present contribution is to describe this articular region and to analyze its potential phylogenetic information. The articular region of Vegavis shows a unique combination of characters that separates it from most Mesozoic lineages. On the contrary, its anatomy is congruent with that of neornithine birds, and particularly from the neoavian clade Aequorlitornithes. Detailed comparisons led to the recognition of several shared features, including a well-developed transverse crest posterior to the articular cotyles, that bears a well-developed lateral tubercle; a short and ventrally deflected retroarticular process; a dorsally exposed posterior fossa; tree cotyles for jaw articulation, with a welldeveloped caudal cotyle fused to the medial cotyle; and lateral crest anteriorly projected with respect to the lateral cotyle. The three-cotyle articulation of the jaw of Vegavis invited us to review skull anatomy of its close kin Polarornis. A review of the bones of Polarornis indicates that the element previously identified as a quadrate is an uncertain bone, and thus, skull-jaw articulation of this taxon remains unknown. In contrast with previous contributions, we were not able to find diagnostic features of the Galloanserae clade on Vegavis jaw. The neoavian-like jaw of Vegavis contrasts with the anseriform signature of its postcranium, suggesting that this bird held some kind of morphological mosaicism on its skeleton.
... Though our recently collected Eocene material is fragmentary, it provides additional support for records of the presence of mammalian and avian taxa previously proposed from even more fragmentary and controversial single elements. These new records are also consistent with those expected for the Eocene of Antarctica given longstanding hypotheses of a biotic connection between Antarctica and South America during the Paleogene as well as penecontemporaneous fossil discoveries from Patagonia (see Reguero, Marenssi & Santillana, 2002;Sallaberry et al., 2010;Yury-Yáñez et al., 2012;Acosta Hospitaleche & Olivero, 2016;Reguero et al., 2014). The Eocene mammalian record otherwise comprises gondwanatheres, marsupials, cetaceans, 'South American native ungulates' (e.g., a litoptern, astrapotheres), and additional, enigmatic eutherians (Woodburne & Zinsmeister, 1984;Borsuk-Bialynicka, 1988;Case, Woodburne & Chaney, 1988;Bond et al., 1990;Hooker, 1992;Marenssi et al., 1994;Bargo & Reguero, 1998;Fostowicz-Frelik, 2003;Reguero & Gasparini, 2006;Case, 2006;Reguero et al., 2013;Gelfo et al., 2015;Buono et al., 2016;reviewed in Gelfo et al., 2019). ...
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The middle-late Eocene of Antarctica was characterized by dramatic change as the continent became isolated from the other southern landmasses and the Antarctic Circumpolar Current formed. These events were crucial to the formation of the permanent Antarctic ice cap, affecting both regional and global climate change. Our best insight into how life in the high latitudes responded to this climatic shift is provided by the fossil record from Seymour Island, near the eastern coast of the Antarctic Peninsula. While extensive collections have been made from the La Meseta and Submeseta formations of this island, few avian taxa other than penguins have been described and mammalian postcranial remains have been scarce. Here, we report new fossils from Seymour Island collected by the Antarctic Peninsula Paleontology Project. These include a mammalian metapodial referred to Xenarthra and avian material including a partial tarsometatarsus referred to Gruiformes (cranes, rails, and allies). Penguin fossils (Sphenisciformes) continue to be most abundant in new collections from these deposits. We report several penguin remains including a large spear-like mandible preserving the symphysis, a nearly complete tarsometatarsus with similarities to the large penguin clade Palaeeudyptes but possibly representing a new species, and two small partial tarsometatarsi belonging to the genus Delphinornis. These findings expand our view of Eocene vertebrate faunas on Antarctica. Specifically, the new remains referred to Gruiformes and Xenarthra provide support for previously proposed, but contentious, earliest occurrence records of these clades on the continent.
Galloanseres, the clade including galliform and anseriform birds, is supported by virtually all analyses of different kinds of molecular data and also resulted from analyses of morphological data. A recent study obtained an early Eocene date for the split of galliform and anseriform birds, some 55 million years. However, this divergence estimate is in clear conflict with the fossil record, which includes morphologically disparate stem group representatives of both Galliformes and Anseriformes from deposits of that age (anseriform birds have an even earlier fossil record). Extant Galloanseres are mainly characterized by morphological apomorphies that concern skull features. The postcranial skeleton of extant Galliformes and Anseriformes is quite different, but the morphology of Paleogene stem group Galliformes bridges the morphological gap between the extant taxa. Various ecomorphologically disparate Paleogene taxa were assigned to the Galloanseres. The morphological and ecological diversity within Paleogene Galloanseres, therefore, appears to have been extraordinarily high, including giant flightless ground birds with greatly reduced wings, long-legged filter-feeders, and pelagic taxa with wingspans of 4–5 m.
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The fossil record of Late Cretaceous–Paleogene modern birds in the Southern Hemisphere includes the Maastrichtian Neogaeornis wetzeli from Chile, Polarornis gregorii and Vegavis iaai from Antarctica, and Australornis lovei from the Paleogene of New Zealand. The recent finding of a new and nearly complete Vegavis skeleton constitutes the most informative source for anatomical comparisons among Australornis, Polarornis, and Vegavis. The present contribution includes, for the first time, Vegavis, Polarornis, and Australornis in a comprehensive phylogenetic analysis. This analysis resulted in the recognition of these taxa as a clade of basal Anseriformes that we call Vegaviidae. Vegaviids share a combination of characters related to diving adaptations, including compact and thickened cortex of hindlimb bones, femur with anteroposteriorly compressed and bowed shaft, deep and wide popliteal fossa delimited by a medial ridge, tibiotarsus showing notably proximally expanded cnemial crests, expanded fibular crest, anteroposterior compression of the tibial shaft, and a tarsometatarsus with a strong transverse compression of the shaft. Isolated bones coming from the Cretaceous and Paleogene of South America, Antarctica, and New Zealand are also referred to here to Vegaviidae and support the view that these basal anseriforms were abundant and diverse at high southern latitudes. Moreover, vegaviids represent the first avian lineage to have definitely crossed the K–Pg boundary, supporting the idea that some avian clades were not affected by the end Mesozoic mass extinction event, countering previous interpretations. Recognition of Vegaviidae indicates that modern birds were diversified in southern continents by the Cretaceous and reinforces the hypothesis indicating the important role of Gondwana for the evolutionary history of Anseriformes and Neornithes as a whole.
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Se lista y comenta el registro de aves fósiles de Chile Continental. El registro más antiguo corresponde al gaviforme fósil Neogaeornis wetzeli Lambrecht, 1929, proveniente de Formación Quiriquina (Maastrichtiano superior). Las aves paleógenas registradas hasta el momento provienen de los Estratos de Algarrobo, Región de Valparaíso y de las formaciones Loreto, Río Turbio y Man Aike en la Región de Magallanes, todas asignables al Eoceno medio-tardío. La mayor parte de estos restos son fragmentarios, aunque bastante informativos en términos paleobiogeográficos. El ensamble faunístico de Formación Río Turbio en la Sierra Dorotea refleja una estrecha relación con la fauna conocida en el Eoceno medio-superior de la Formación La Meseta en Isla Seymour, Antártica. El registro de aves neógenas en Chile es más extenso y, en consecuencia, mejor estudiado, encontrándose representado en el Mioceno inferior de la Formación Cura-Mallín, el Mioceno medio-Plioceno superior de la Formación Bahía Inglesa y de Formación Coquimbo, y en el Plioceno superior de las formaciones La Portada y Horcón. La Formación Bahía Inglesa ha aportado con el mayor número de especímenes fósiles, estando presentes grupos tales como los Sphenisciformes (pingüinos), el cual es el mejor representado en la diversidad de aves del Cenozoico. Para el Pleistoceno, se reconocen ensambles marinos en la Región de Atacama, provenientes de la unidad Estratos de Caldera. Por otra parte, aves continentales de ambientes lacustres asociadas a restos arqueológicos se reconocen en el sitio Laguna de Tagua Tagua.
Several advances have been made on the understanding of the biotic and environmental history of South America and Antarctica including the discovery of additional fossil sites coupled with progress from multidisciplinary analyses encompassing tectonic, isotopic, and radiochemical dating and molecular studies in modern forms. This also changed the knowledge about birds. Characters of the South American (SAn) avian fossil record are: (1) presence of taxa with uncertain affinities and the absence of Passeriformes during the Paleogene; (2) progressive and accelerated increase of species starting at the Neogene (Miocene); (3) dispersal of important extinct lineages (e.g. Phorusrhacidae, Teratornithidae) to North America after the connection between both Americas; (4) scarce endemic species that are members of clades with major diversification during the Neogene (e.g., Cariamiformes) or that inhabits mainly in the southern hemisphere (e.g., Anhingidae); (5) highly diverse living groups with limited (e.g., Passeriformes) or none (e.g., Apodiformes) fossil record whose stem-groups are registered in Europe; (6) Absence of the most extant SAn bird lineages; (7) predominate of the zoophagous birds (>60 %) in all the associations (13) under scrutiny. Changes in diversity of the SAn birds during the Cenozoic could have been the result of the action of different processes (dispersal, vicariance, extirpations or extinctions) that affect groups in different ways.
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In this classic segment, many tectonic processes, like flat-subduction, terrane accretion and steepening of the subduction, among others, provide a robust framework for their understanding. Five orogenic cycles, with variations in location and type of magmatism, tectonic regimes and development of different accretionary prisms, show a complex evolution. Accretion of a continental terrane in the Pampean cycle exhumed lower to middle crust in Early Cambrian. The Ordovician magmatic arc, associated metamorphism and foreland basin formation characterized the Famatinian cycle. In Late Devonian, the collision of Chilenia and associated highpressure/ low-temperature metamorphism contrasts with the late Palaeozoic accretionary prisms. Contractional deformation in Early to Middle Permian was followed by extension and rhyolitic (Choiyoi) magmatism. Triassic to earliest Jurassic rifting was followed by subduction and extension, dominated by Pacific marine ingressions, during Jurassic and Early Cretaceous. The Late Cretaceous was characterized by uplift and exhumation of the Andean Cordillera. An Atlantic ingression occurred in latest Cretaceous. Cenozoic contraction and uplift pulses alternate with Oligocene extension. Late Cenozoic subduction was characterized by the Pampean flat-subduction, the clockwise block tectonic rotations in the normal subduction segments and the magmatism in Payenia. These processes provide evidence that the Andean tectonic model is far from a straightforward geological evolution.
We describe a new species of penguin, Spheniscus chilensis, from Cuenca del Tiburón, late Pliocene, northern Chile. This species was found in association with a small species of cormorant. Phalacrocorax sp., and a caracara, Milvago sp., and is the first Pliocene penguin to be described from South America. Other vertebrates at this site include fish, sharks, and cetaceans. An extensive invertebrate fauna, including the late Pliocene muricid gastropod Herminespina mirabilis, also is present. The avifauna suggests a low diversity of seabirds existed in northern Chile from the late Pliocene to the present, unlike the much higher diversity found in Patagonia in the late Oligocene/early Miocene.
Three new penguin skulls (Spheniscidae), assigned to the new species Pygoscelis calderensis sp. nov. from the Bahía Inglesa Formation of Middle Miocene-Pliocene age located south of Caldera on the coast of the III Región de Atacama, Chile (27°00′S, 70°45′W to 28°00′, 71°00′W), are described. This finding broadens the geographic and chronologic distribution of the genus, constituting its most northern record. Before the present work, the genus was known from the Late Pliocene of New Zealand. This record, together with other faunistic evidences, suggests the existence of periods or cold oceanic currents during the Neogene.