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Ornithuromorpha is the most inclusive clade containing extant birds but not the Mesozoic Enantiornithes. The early evolutionary history of this avian clade has been advanced with recent discoveries from Cretaceous deposits, indicating that Ornithuromorpha and Enantiornithes are the two major avian groups in Mesozoic. Here we report on a new ornithuromorph bird, Archaeornithura meemannae gen. et sp. nov., from the second oldest avian-bearing deposits (130.7[thinsp]Ma) in the world. The new taxon is referable to the Hongshanornithidae and constitutes the oldest record of the Ornithuromorpha. However, A. meemannae shows few primitive features relative to younger hongshanornithids and is deeply nested within the Hongshanornithidae, suggesting that this clade is already well established. The new discovery extends the record of Ornithuromorpha by five to six million years, which in turn pushes back the divergence times of early avian lingeages into the Early Cretaceous.
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Received 6 Jan 2015 |Accepted 20 Mar 2015 |Published 5 May 2015
The oldest record of ornithuromorpha from the
early cretaceous of China
Min Wang1, Xiaoting Zheng2,3, Jingmai K. O’Connor1, Graeme T. Lloyd4, Xiaoli Wang2,3, Yan Wang2,3,
Xiaomei Zhang2,3 & Zhonghe Zhou1
Ornithuromorpha is the most inclusive clade containing extant birds but not the Mesozoic
Enantiornithes. The early evolutionary history of this avian clade has been advanced
with recent discoveries from Cretaceous deposits, indicating that Ornithuromorpha and
Enantiornithes are the two major avian groups in Mesozoic. Here we report on a new
ornithuromorph bird, Archaeornithura meemannae gen. et sp. nov., from the second oldest
avian-bearing deposits (130.7 Ma) in the world. The new taxon is referable to the
Hongshanornithidae and constitutes the oldest record of the Ornithuromorpha. However,
A. meemannae shows few primitive features relative to younger hongshanornithids and is
deeply nested within the Hongshanornithidae, suggesting that this clade is already well
established. The new discovery extends the record of Ornithuromorpha by five to six million
years, which in turn pushes back the divergence times of early avian lingeages into the Early
Cretaceous.
DOI: 10.1038/ncomms7987 OPEN
1Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology,
Chinese Academy of Sciences, Beijing 100044, China. 2Institue of Geology and Paleontology, Linyi University, Linyi, Shandong 276000, China.
3Tianyu Natural History Museum of Shandong, Pingyi, Shandong 273300, China. 4Department of Biological Sciences, Faculty of Science, Macquarie
University, Sydney, New South Wales 2019, Australia. Correspondence and requests for materials should be addressed to M.W. (email: wangmin@ivpp.ac.cn)
or to Z.Z. (email: zhouzhonghe@ivpp.ac.cn).
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Ornithuromorpha is the clade of birds that all living birds
but not Enantiornithes nest in refs 1,2. Until now the
earliest record of this group was from the lower
Cretaceous Yixian Formation (125 Ma), the middle phase in the
evolution of the Jehol Biota—the most important and diverse
fossil avifauna known to science1,3,4. More than half the known
diversity of Mesozoic birds belongs to this biota, which includes,
from the oldest to the youngest, the Protopteryx horizon and the
Yixian and Jiufotang Formations, which together encompass over
ten million years of avian evolution (130.7–120 Ma)5. Bio- and
lithostratigraphic works confirmed that the Protopteryx-bearing
deposits in Sichakou basin of Fengning Country are referable to
the interbedded shales from the lower part of the Huajiying
Formation5,6. Recent 40Ar/39Ar dating produced a weighted
mean age of 130.7 Ma for this horizon7. Therefore, the Huajiying
Formation is the second oldest avian-bearing deposit in the
world, only after the Upper Jurassic Solnhofen Limestones that
preserve Archaeopteryx in Germany6. Only three avian taxa have
been collected from this horizon: the basal confuciusornithiform
Eoconfuciusornis and two enantiornithines Protopteryx
and Eopengornis8–10. Here we report on the first two
ornithuromorph fossils from the same locality as the holotype
of Protopteryx fengningensis in Sichakou basin8, which constitute
the earliest known record of Ornithuromorpha. These two
specimens are referable to a single taxon, which appears to be
deeply nested within the Hongshanornithidae, a fairly diverse
clade of small, specialized wading ornithuromorphs. Currently,
four hongshanornithids, Hongshanornis longicresta,Longicrusavis
houi,Parahongshanornis chaoyangensis and Tianyuornis cheni,
have been reported from the Yixian and Jiufotang Formations in
Inner Mongolia and Liaoning2,11–14. These new specimens
reported here push back the first appearance datum of
Ornithuromorpha by approximately six million years.
Results
Systematic paleontology.
Aves
Ornithothoraces
Ornithuromorpha
Hongshanornithidae
Type genus. Hongshanornis, Zhou and Zhang11.
Archaeornithura meemannae gen. et sp. nov.
Etymology. The generic name is derived from Greek
Archae’ and ‘ornithura’, meaning ‘ancient ornithuromorph’.
The specific name is in honour of Dr Meemann Chang for
her continuous support of the study of the Jehol Biota.
Holotype. An articulated partial skeleton with feathers
(STM7-145), housed at the Tianyu Natural History Museum
of Shandong (STM), China (Fig. 1).
Paratype. An articulated partial skeleton with feathers
(STM7-163; Supplementary Fig. 1).
Locality and horizon. Protopteryx horizon in Sichakou
basin, Fengning County, Hebei, northeastern China; Lower
Cretaceous Huajiying Formation6,7.
Differential diagnosis. The new taxon is referable to the
Hongshanornithidae and can be distinguished from the
known hongshanornithids by the following combined
features: it differs from Hongshanornis and Longicrusavis,
in that the cranial margin of the sternum is strongly vaulted;
it is distinguished from Hongshanornis and Parahongsha-
nornis, in that the zyphoid process of the sternum is
well developed and squared; it differs from other
hongshanornithids except Longicrusavis, in that the alular
digit extends further distally than the major metacarpal; it
is distinguishable from other hongshanornithids except
Parahongshanornis, in that the penultimate phalanx of the
major digit is longer than the preceding phalanx; and the
new taxon has proportionally shorter femur relative to the
tarsometatarsus.
Description. The skull is not well preserved in either specimen
(Fig. 1; Supplementary Fig. 1). The cervical vertebrae are poorly
preserved in articulation with the skull; 10 vertebrae are preserved
including the ring-like axis, although the exact position of
the cervicothoracic transition cannot be determined due to
poor preservation. The vertebrae are clearly not elongated,
being approximately equal in width and length, as in other
hongshanornithids (Figs 1 and 2b,c; Supplementary Fig. 1). The
thoracic vertebrae are only preserved in the counter slab of
STM7-145, covered by the sternum. The synsacrum appears
to comprise 9–10 vertebrae, although preservation makes this
estimate equivocal. Six free caudals are followed by a poorly
preserved pygostyle (Fig. 3e). The transverse processes of the
caudal vertebrae are less than the width of the centrum in length
and caudolaterally directed, at least in the first free caudal. Two
well-preserved uncinate processes are preserved in the counter
slab of STM7-163, and they are straight and tapered (Fig. 2a).
Although not in articulation with the ribs, we infer they would
have crossed at least one rib, reaching and potentially crossing a
second. Four sets of gastralia are preserved in articulation in
STM7-163 (Supplementary Fig. 2b).
The scapula is curved, as in other ornithuromorph birds, but
the distal end is not well preserved in either specimen (Figs 1
and 2c). The furcula is typically hongshanornithid: delicate,
U-shaped, with tapered omal margins and a small tubercle-like
hypocleidium as in Tianyuornis and Parahongshanornis12–14,
which, however, is short and sharply tapered in Hongshanornis
(Fig. 2)11. In contrast, a hypocleidium is absent from most other
Cretaceous ornithuromorphs, although a short one has been
reported in Schizooura15. The furcular symphysis is much
thicker craniocaudally compared with the omal rami as in
Hongshanornis, whereas the furcula appears to be nearly of equal
thickness throughout in Longirostravis and Tianyuornis12,13. The
coracoid is narrow along the proximal half, and wide distally with
a well-developed sternocoracoidal process (Fig. 2b), as in
hongshanornithids and most other ornithuromorphs2,12–14.
Although poorly preserved, a procoracoid process is visible on
the right coracoid in the counter slab of both specimens; it is
medially oriented although the distal half appears more cranially
directed (Fig. 2b). This process is perforated at the base by a small
circular supracoracoidal nerve foramen. The coracoid is preserved
in the dorsal view in the counter slab of STM7-163 (Fig. 2b); the
acrocoracoid is blunt, the scapular cotyla is deeply concave, and
the laterally positioned glenoid is developed as a weak convexity.
Distally, the corpus is concave, more so than the condition in
Yixianornis but not so deeply as in some Late Cretaceous
enantiornithines16. The sternum is not well preserved, but a
fragment in STM7-163 indicates the rostral margin is vaulted as
in Tianyuornis and Parahongshanornis (Fig. 2d,g,h)13,14,
but more pointed than in Longicrusavis and Hongshanornis,in
which the cranial margin is broad and parabolic (Fig. 2e,f)2,11,12.
A well-developed zyphoid process is present and squared in
shape, as in Longicrusavis and Tianyuornis (Fig. 2a,f,g)12,13,
whereas the process is absent in Hongshanornis and
Parahongshanornis, and the corresponding lateral margin only
bulges laterally (Fig. 2e,h)11,14. A second fragment in the same
slab indicates that the lateral trabecula was short and narrow
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as in other hongshanornithids, with a distinct triangular
distal expansion similar to that of Tianyuornis but smaller
(Supplementary Fig. 2a)13.
The humerus is short and robust with a large rounded
deltopectoral crest that extends 44% the length of the humerus
and slightly exceeds the width of the shaft, as in other
hongshanornithids (Fig. 3a). The distal margin is perpendicular
to the shaft. The condyles are well developed and bulbous, and a
dorsal supracondylar process is present as in other hongshanor-
nithids (Fig. 3a; Supplementary Fig. 2d)2,12; however, the process
has so far been reported only in Ichthyornis among other
Mesozoic birds2,17. The ulna is bowed and more robust than the
straight radius as in all basal birds. An olecranon process is not
developed. The carpometacarpus appears to be fused proximally
but not distally in STM7-145. All the metacarpals are straight,
and the minor metacarpal is less than half the thickness of the
major metacarpal. The alular metacarpal bears a small extensor
process that is less than half the width of the articular facet of this
metacarpal. The alular digit is long, with half of the ungual
extending just beyond the distal margin of the major metacarpal
as in Longicrusavis, whereas in other hongshanornithids, only the
tip of the ungual slightly surpasses the distal end of the major
metacarpal (Fig. 3a,c). The ungual phalanx of the alular digit is
larger and more recurved than that of the major digit, as in other
hongshanornithids2,11–14. The first phalanx of the major digit is
mediolaterally compressed and caudally expanded, as in other
ornithuromorphs. As in Parahongshanornis, the penultimate
phalanx is longer than the preceding phalanx, whereas these two
phalanges are subequal in length in other hongshanornithids
(Table 1). The minor digit only preserves a single reduced
wedge-shaped phalanx that tapers distally. A second phalanx,
which is extremely reduced in other hongshanornithids2,11–14,
may have being missing due to preservation. Similar to
other hongshanornithids, the forelimb is much shorter than
the hindlimb, with an intermembral index (humerus þulna/
femur þtibiotarsus) of B0.84 (Table 1), whereas the forelimb is
typically longer in other Early Cretaceous ornithuromorphs18,19.
The pelvic girdle is not well preserved in either specimen; the
ilium is displaced cranially in STM7-145. Visible in the main slab,
the cranial margin is convex, while the lateral margin proximal to
the acetabulum is concave; the two margins are separated by a
weakly developed ventral hook present in most ornithuromorphs
and some enantiornithines. The pubes are long and contact along
their distal tenth but remain unfused, as in Hongshanornis
(Supplementary Fig. 2c). Although incomplete, the distal ends of
pubes are well preserved in lateral and medial views in the
counter slab of STM7-163, revealing a small distally expanded
boot as in Hongshanornis and Parahongshanornis (unclear in
Tianyuornis and Longirostravis; Fig. 3d,e)2,14. The ischia appear
to be just over half the length of the pubes, straight, narrow and
tapered along their distal halves (Fig. 3e), lacking the low dorsal
process located mid-corpus and the concave ventral margin
present in most other ornithuromorphs, including Yixianornis
and Piscivoravis20,21.
The femora are short and fairly robust, approximately equal in
length to the tarsometatarsi; in contrast, the femur is considerably
longer than the latter in most other basal birds, including
Jeholornis,Sapeornis,Confuciusornis, enantiornithines and
ornithuromorphs18,19. The tibiotarsus is proportionally shorter
than other hongshanornithids relative to the tarsometatarsus. As
in Longicrusavis, the fibula is preserved bowing out from the
tibiotarsus, not appressed against it, and only appears to extend to
the midshaft of the tibiotarsus12. The proximal medial surface
bears a shallow excavation, visible on the left side in the counter
slab of STM7-163.
The tarsometatarsi are well preserved in the main slab of
STM7-163 (Fig. 3f). They are fully fused, although the individual
metatarsals can be distinguished. Overall, the foot is very similar
to other hongshanornithids2,11–14. The proximal half of
metatarsal III is plantarly displaced relative to metatarsals II
and IV, as in all ornithuromorphs. Metatarsal III is the longest
and metatarsals II and IV end approximately at the same level.
The hallux is small and placed above the trochlea of the
other digits as in most ornithuromorphs including other
hongshanornithids. The first phalanx is approximately as long
as metatarsal I itself; the ungual phalanx is more strongly
recurved than that of the other digits. As in other
hongshanornithids, the phalanges decease in length distally,
digit III is the longest and digit II is substantially shorter than IV.
Both specimens preserve nearly complete plumage (Figs 1
and 4; Supplementary Fig. 1). Six long asymmetrical primary
remiges are preserved in the left wing of the main slab in the
ba
cv
co
hu
ra
ul
al
ma
mi
fe
ti
fi
tm
d I
d II
d II I
d IV
fu
sc st
pu
re pr
ul
ra
hu
fe
ti
fi
tm
re
cv
Figure 1 | Holotype of Archaeornithura meemannae gen. et sp. nov., STM7-145. (a) Main slab; (b) counter slab. Anatomical abbreviations: al, alular
digit; ba, basicranium; co, coracoid; cv, cervical vertebrae; d I–IV, pedal digit I–IV; fe, femur; fi, fibula; fu, furcula; hu, humerus; ma, major digit; mi, minor
digit; pr, primary remiges; pu, pubis; ra, radius; re, rectrices; sc, scapula; st, sternum; ti, tibiotarsus; tm, tarsometatarsus; ul, ulna. Scale bars, 10 mm.
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holotype (Fig. 4a); the second and third feathers are the longest.
The primary remiges are overlain by a layer of short feathers,
which measure just under half the length of the primary remiges
themselves—we interpret these feathers as the dorsal coverts
(Fig. 4a,b). They appear to be symmetrical, definitely lacking the
strong asymmetry present in the primary remiges in which the
leading edge vane is less than one-third the width of the trailing
edge vane (Fig. 4a). Portions of a few secondary feathers are also
preserved; these appear to be narrower than the primary remiges
and symmetrical with rounded distal margins. An alula is
preserved in both specimens, composed of at least three feathers
in STM7-163, visible where the alular digit is disarticulated on the
left side (Fig. 4d). The rounded distal margins of three large
symmetrical pennaceous feathers are preserved near the right foot
in STM7-145 (Figs 1 and 4b). These feathers are staggered so that
each medial feather ends distal to the lateral feather, suggesting
that these feathers represent the distal portion of an incomplete
fan-shaped array of rectrices, like that present in Hongshanornis
(IVPP V14533 and DNHM D2945/6)2.
Short rachis-less covert feathers are found all over the body,
particularly well preserved in STM7-163 (Supplementary Fig. 1).
These feathers cover the head, neck, shoulders, extend off the
co
hu
fu
cv
zp
st
uc
fu
co
sl hy
pc
ne
sc
co
pc
hy
st
ca
fu
zp
lt
zp
hy
Figure 2 | Pectoral girdle and sternum of Archaeornithura meemannae gen. et sp. nov., in comparison with other hongshanornithids. (a) STM7-163,
counter slab (zyphoid process of the sternum is outlined by a dash line); (b) STM7-145, main slab; (c) photograph and (d) line drawing of STM7-145,
counter slab. Line drawing (not scaled) of furcula and sternum of other hongshanornithids: (e)Hongshanornis longicresta;(f)Longicrusavis houi;
(g)Tianyuornis cheni;(h)Parahongshanornis chaoyangensis. Anatomical abbreviations: ca, carina; co, coracoid; cv, cervical vertebrae; fu, furcula; hy,
hypocleidium; lt, lateral trabecula of the sternum; ne, supracoracoidal nerve foramen; pc, procoracoid process; sc, scapula; sl, sternocoracoidal process;
st, sternum; uc, uncinate process; zp, zyphoid process of the sternum. Scale bars, 5 mm.
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proximal ulna and humerus and line the caudal end of the body
(Fig. 4c; Supplementary Fig. 1). These feathers are notably absent
from the distal three-quarters of the tibiotarsus in both specimens
(Figs 1 and 4a; Supplementary Fig. 1), consistent with the wading
habitat inferred for hongshanornithids12.
Discussion
Archaeornithura is referable to the Hongshanornithidae, which is
distinguishable from other Cretaceous ornithuromorphs by
the following synapomorphies: the U-shaped furcula bears a
tubercle-like hypocleidium; the humerus has a well-developed
supracondylar process; the manus is longer than the humerus; the
forelimb is shorter than the hindlimb with an intermembral index
of about 0.8; and the femur and tarsometatarsus are subequal in
length, while the former is considerably longer in most other
basal birds. Phylogenetic analysis was conducted using a
comprehensive matrix targeted at Mesozoic birds (58 taxa
and 262 characters; Supplementary Data 1 and Supplementary
Data 2)22; the results confirm the close affinity between the new
specimens and younger hongshanornithids, resolving all
purported members together in a clade, the Hongshanornithidae
(Fig. 5; Supplementary Fig. 3). This represents the most diverse
recognized clade of Early Cretaceous ornithuromorphs.
Synapomorphies of the Hongshanornithidae retained from the
analysis include: teeth present throughout the premaxillary
(character 4:0); mandibular ramus sigmoidal in shape (character
42:1); acromion process of scapula nearly parallel to the scapular
shaft in costal or lateral view (character 98:1); dorsal
supracondylar process of humerus developed (character 134:2);
second phalanx of the major digit longer than the proximal one
(character 171:0); intermembral index between 0.7 and 0.9
(character 177:1); the claw of the fourth pedal digit smaller
than that of other digits (character 256:1); and the ratio (length of
del
ul
ra
hu
sp
am
al
ma
mim mam
mi
pu
pb pb
pu
pb
is
py
is
ti
tm
mt I d I
d II
d III
d IV
ca
1
2
3
4
5
6
Figure 3 | Detail anatomy of Archaeornithura meemannae gen. et sp. nov. (a) Photograph and (b) line drawing of the left wing, STM7-145, counter
slab; (c) line drawing of hands of other hongshanornithids (not scaled; from left): Hongshanornis longicresta,Longicrusavis houi,Tianyuornis cheni,
Parahongshanornis chaoyangensis;(d) STM7-163, counter slab; (e) STM7-163, main slab; (f) feet, STM7-163, main slab. Anatomical abbreviations:
al, alular digit; am, alular metacarpal; ca, caudal vertebrae (six vertebrae counted); del, deltopectoral crest; d I–IV, pedal digit I–IV; hu, humerus; is, ischium;
ma, major digit; mam, major metacarpal; mi, minor digit; mim, minor metacarpal; mt I, metatarsal I; pb, pubic boot; pu, pubis; py, pygostyle; ra, radius;
sp, supracondylar process; ti, tibiotarsus; tm, tarsometatarsus; ul, ulna. Scale bars, 10mm (a,f), 5 mm (d,e).
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tibiotarsus/tarsometatarsus) between 2 and 1.6 (character 257:1).
Archaeornithura is resolved to be the sister taxon to the younger
Tianyuornis and this clade is supported by two synapomorphies:
outermost trabecula of sternum with a simple bulb-like distal
expansion (character 113:1; Supplementary Fig. 2a) and
metatarsals II–IV partially fused with discernible sutural
contacts (222:1; Fig. 3f). It is notable that, despite being the
oldest recognized ornithuromorph, Archaeornithura is deeply
nested within the Hongshanornithidae, which itself is more
deeply nested within Ornithuromorpha than some taxa known
entirely from younger deposits15,17,18,21,22. These inconsistencies
between stratigraphy and phylogeny require the presence
of ghost lineages and a much earlier origination date for
the Ornithuromorpha, which in turn pushes back the
Table 1 | Comparative measurements of Archaeornithura meemannae gen. et sp. nov. and other hongshanornithid taxa.
Elements STM 7-145 STM 7-163 IVPP V 14533 DNHM D2945 PKUP 1069 PMOL-AB00161 STM7-53
Coracoid 15.4 12.7 11.7 12.7 14.7
Scapula 423.2 22.4 23.1 424.5
Humerus 25.9 27.5 26.0 22.9 26.0 29.4 25.4
Ulna 25.8 28.3 24.4 23.9 25.0 28.4 26.4
Radius 23.9 26.0 23.0 23.1 24.0 26.8 24.6
Carpometacarpus 13.1 13.8 11.8 12.6 13.1 11.4 13.2
Alular digit 1 6.0 7.6 6.3 6.6 6.9 6.7 6.6
Alular digit 2 3.0 3.9 2.8 2.8 4.3 2.7 2.9
Major digit 1 6.6 6.8 5.8 6.6 7.0 7.1 6.9
Major digit 2 7.6 7.0 5.9 6.8 7.3 8.0 7.0
Major digit 3 2.4 3.0 2.5 3.4 2.6
Minor digit 1 3.3 2.8 4.0 3.2, 3.5 3.3
Femur 23.8 22 24.3 24.8 24.8
Tibiotarsus 38.0 37.5 38 34.6 37.6 41.3 39.0
Tarsometatarsus 23.0 21.0 19.1 21.5 21.2 23.1
(Humerus þulna)/(femur þtibiotarsus) 0.84 0.84 0.82 0.87 0.81
Archaeornithura meemannae (STM7-145, STM7-163), Hongshanornis longicresta (holotype, IVPP V 14533; paratype, DNHM D2945), Longicrusavis houi (holotype, PKUP V1069), Tianyuornis cheni (holotype,
STM7-53) and Parahongshanornis chaoyangensis (holotype, PMOL-AB00161). Lengths are measured in millimetres.
dc
pr
pr
re af
Figure 4 | Plumage of Archaeornithura meemannae gen. et sp. nov. (a) Left wing, STM-7-145, main slab; (b) right wing, STM-7-145, main slab;
(c) covert feathers over the skull and neck, STM 7-163, counter slab; (d) alular feathers on the left alular digit, STM7-163, main slab. Abbreviations:
af, alular feather; dc, dorsal coverts; pr, primary remiges; re, rectrices. Scale bars, 10 mm (ac), 5 mm (d).
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divergence time with enantiornithines and other primitive avian
lineages.
Archaeornithura preserves fairly advanced plumage including a
well-developed alula and fan-shaped rectrices (Figs 1 and 4;
Supplementary Fig. 1). Both the alula (bastard wing) and a fan-
shaped tail are aerodynamically important for living birds during
slow flight and increases manoeuvrability23,24. These advanced
feather structures are inferred to be plesiomorphic at least to
Ornithothoraces2,10; an alula is also present in the basal
enantiornithine Protopteryx from the same locality8. Because
the alular digit is well developed in both hongshanornithids and
Protopteryx (extends beyond the distal end of the major
metacarpal), the morphology of the alula would be expected to
somewhat differ from that in living birds. However, preservation
of the alula in a Mesozoic bird has never been clearer than as
preserved in STM7-163 (Fig. 4d), which reveals a morphology
that is remarkably similar to that in living birds: it is formed by at
least three feathers (three to five in living birds), with the short
proximal feather ending level with the alular digit and the longer
feathers extending to the end of the major digit. Both
Archaeornithura and Hongshanornis preserve a fan-shaped
array of rectrices2, a feature plesiomorphic to Ornithuromorpha
Eoconfuciusornis
Changchengornis
Dromaeosauridae
Archaeopteryx
Jeholornis
Confuciusornis dui
Jinzhouornis
Confuciusornis sanctus
Sapeornis
Protopteryx
Patagopteryx
Hongshanornis
Parahongshanornis
Yanornis
Yixianornis
Piscivoravis
Gansus
Apsaravis
Hesperornis
Ichthyornis
Longipteryx
Shanweiniao
Eoenantiornis
Rapaxavis
Longicrusavis
Tianyuornis
Archaeornithura
Eoalulavis
Concornis
Fortunguavis
Vescornis Neuquenornis
Gobipteryx
Longirostravis
Boluochia
Eocathayornis
Jianchangornis
Archaeorhynchus
Schizooura Vorona
Songlingornis
Vegavis
Enaliornis
Baptornis advenus
Baptornis varneri
Parahesperornis
Pengornis
Eopengornis
Cathayornis
Qiliania
Shenqiornis Sulcavis
Parabohaiornis
Longusunguis
Zhouornis
Bohaiornis
Neornithes
Aves
Pygostylia
Enantiornithines
Ornithothoraces
Ornithuromorpha
Confuciusornithidae
Pengornithidae
Bohaiornithidae
Longipterygidae
Hongshanornithidae
c
d
e
100
3
111
1112
2
1111
1
1
11
1
11
1
1
1
11
1
1
3
3
3
250/
1
e
d
c
b
a
a
b
54/159/3
54/4
80/2
70/1
82/2
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69/1
62/2
99/11
Figure 5 | Cladogram showing the systematic position of Archaeornithura meemannae among Mesozoic birds. Bootstrap and bremer values are labelled
to the corresponding nodes in normal and bold italic formats, respectively.
NATURE COMMUNICATIONS | DOI: 10.1038/ncomms7987 ARTICLE
NATURE COMMUNICATIONS | 6:6987 | DOI: 10.1038/ncomms7987 | www.nature.com/naturecommunications 7
&2015 Macmillan Publishers Limited. All rights reserved.
and apparently lost in Enantiornithes10. Enantiornithines and the
Confuciusornithiformes typically have only a pair of elongated
rachis-dominant rectrices8,9,25,26. The rachis of these feathers is
proportionately wide and always preserves a longitudinal stripe,
which is interpreted as a central groove in some studies10,26. More
recently, the same striped morphology was recognized in the
primary feathers of Confuciusornis and enantiornithines,
supporting hypotheses that rachis-dominated feathers are
modified flight feathers10.Archaeornithura documents this
feather morphology for the first time in the Ornithuromorpha;
a medial stripe is visible in the rachises of some of the primary
remiges. Although evidence from Archaeopteryx indicates
modern feather morphology including fully pennaceous coverts
and rachises that clearly lacked a longitudinal groove27, these
features are absent in Jehol birds despite the huge wealth of
specimens25,26. This suggests that modern feather morphologies
evolved independently within the Archaeopteryx lineage and a
derived subset of ornithuromorphs.
Bird fossils are extremely rare in the Mesozoic fossil record,
and until the wealth of specimens discovered from Early
Cretaceous deposits in northeastern China, very little was known
about the early evolution of birds1,3,4. The Jehol Biota
encapsulates a unique window into the biology and morphology
of the oldest known avifauna; however, this fauna is clearly
already well within the diversification of birds, given that both
ornithothoracine clades are present3,28. Until now no
ornithuromorphs had been described from the Huajiying
Formation, which preserves very few fossil birds10;
because diversity is low and geographic area is restricted, the
Huajiying Formation is interpreted as the earliest stage in the
diversification of the Jehol Biota. However, the discovery of
a new species belonging to the specialized clade of waders—the
Hongshanornithidae, indicates that ornithuromorphs themselves
were already quite specialized at this point in their evolution. This
also strongly supports inferences that this clade originated in a
semi-aquatic environment1,29,30.
Methods
Provenance of the two specimens of A. meemannae.The two specimens
(STM7-145, 7-163) of A. meemannae were acquired by the Tianyu Natural History
Museum of Shandong from a fossil dealer. The dealer confirmed that the fossils
were collected from the same locality of the holotype of Protopteryx fengningensis
(IVPP V11665) in Sichakou basin of Fengning Country, Hebei Province, north-
eastern China. Lithostratigraphic and biostratigraphic fieldworks have been
performed in the basin for years, and confirm that the Protopteryx-bearing horizon
belongs to the Lower member of the Huajiying Formation5,6,8. The Cretaceous
Strata cropping out in Sichakou basin consist of the Huajiying Formation and the
overlying Qingshila Formation; the Huajiying Formation consists of lacustrine
deposits with abundant pyroclastics, and all the known fossil birds, including the
two specimens of A. meemannae, were unearthed from the lower part of the
Huajiying Formation (‘Sichakou sedimentary member’ in ref. 6). Currently, no
fossil birds have been reported from the Qingshila Formation. A weighted mean
age of 130.7 Ma was reported using 40Ar/39Ar dating of the K-feldspars samples
from the interbedded tuffs about 6 m below the Protopteryx-bearing layer7, largely
consistent with previous results using the SHRIMP U-Pb method31. The two
specimens of A. meemannae are preserved in slabs that are identical to the matrixes
containing the holotype of Protopteryx fengningensis,Eoconfuciusornis zhengi and
Eopengornis martini, in that all the slabs are composed of tufaceous siltstones,
which are grey in colour and rigid in nature, consistent with mineralogical
composition of the birds-bearing deposits from the lower part of the Huajiying
Formation6. We have compared hundreds fossil birds, housed in the Institute of
Vertebrate Paleontology and Paleoanthropology, which are unearthed from the
Yixian and Jiufotang Formations from a wide geological area in Jehol Biota.
We have noticed that these slabs are off-white (rather than grey as in the
Archaeornithura-bearing slabs) in colour and mainly composed of weakly
laminated siliciclastic sandstones and shales, which are conspicuously softer than
the bird-bearing slabs from the Huajiying Formation (including the slabs
containing A. meemannae). In addition, we have requested the dealer to show us
the exact locality where these two specimens were unearthed, and confirmed that
they were collected from the Huajiying Formation in Sichakou basin. Detail
comparisons and geological correlation indicate that the slabs preserving the two
specimens of A. meemannae are identical in all visible lithological features to the
sediments of the lower part of the Huajiying Formation. Therefore, the provenance
of the two specimens of A. meemannae can be justified. The two specimens of
A. meemannae are housed in the Tianyu Natural History Museum of Shandong
and are publicly accessible.
Phylogenetic analysis.Phylogenetic analysis was performed using the modified
data set of Wang et al.22, a comprehensive morphological character matrix
targeting the phylogeny of Mesozoic birds (Supplementary Data 1 and 2. Rahonavis
was removed from the data set, given the fact that recent studies indicate that
Rahonavis is an unenlagiine dromaeosaurid rather than a bird32,33. Two
enantiornithines, Elsornis and Iberomesornis, were removed because of their
incompleteness. Two recently reported Jehol birds, Eopengornis martini
(enantiornithine) and Piscivoravis lii (ornithuromorph), were added and scored
from their holotypes (STM24-1, IVPP V17078)10,21. All the known
hongshanornithids were included, and Archaeornithura,Parahongshanornis and
Tianyuornis were coded from their corresponding holotypes. The revised data
matrix consists of 58 taxa (55 are Mesozoic birds), scored across 262 morphological
characters. Phylogenetic analysis was conducted using PAUP software package
version 4.0b10 (ref. 34), with the following settings: all characters equally weighted;
unconstrained heuristic search starting with Wagner trees; 1,000 replicates of
random stepwise addition (branch swapping: tree-bisection-reconnection) holding
10 trees at each step; and branches are collapsed to create polytomies if the
minimum branch length is equal to zero. Bootstrap and Bremer values were
calculated as indices of support. Bootstrap values were performed using the TNT
software package (ref. 35) with default setting, except that 1,000 replicates were
used. Only nodes with bootstrap values greater than 50% are shown in Fig. 5.
Bremer values were calculated using the bremer scripts embedded in TNT.
The phylogenetic analysis produced four most parsimonious trees of 997 steps,
and had a consistency index of 0.367 and retention index of 0.684 (Supplementary
Fig. 3). The strict consensus tree is well resolved, and the new cladogram is
essentially consistent with previous studies with regards to the placement of
major clades10,17,18,22,29,36. In the strict consensus tree, Longicrusavis,
Parahongshanornis and Hongshanornis form the successive outgroups to
Tianyuornis þArchaeornithura clade, and these five taxa together constitute a
clade, the Hongshanornithidae (Fig. 5).
Nomenclatural Acts.This published work and the nomenclatural acts it contains
have been registered in ZooBank, the proposed online registration system for the
International Code of Zoological Nomenclature. The ZooBank LSIDs (Life Science
Identifiers) can be resolved and the associated information viewed through any
standard web browser by appending the LSID to the prefix ‘http://zoobank.org/’.
The LSIDs for this publication are: urn:lsid:zoobank.org:pub:B55C95A7-1AB4-
4645-BEA4-FC7EE139C4A7.
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Acknowledgements
We thank Zongda Zhang for the reconstruction of the specimen. This research was
supported by the National Basic Research Program of China (973 Program,
2012CB821906), the National Natural Science Foundation of China (41172020,
41372014, 41472023 and 41172016), the National Science Foundation for Fostering
Talents in Basic Research of the National Natural Science Foundation of China
(J1210008) and the Australian Research Council grant (DE140101879).
Author contributions
Z.Z., X.Z., M.W. and J.K.O’C. designed the project. M.W., Z.Z., J.K.O’C., G.T.L., X.W.,
Y.W. and X.W. performed the research. M.W. performed the phylogenetic analysis.
M.W., Z.Z., J.K.O’C. and G.T.L. wrote the manuscript.
Additional information
Supplementary Information accompanies this paper at http://www.nature.com/
naturecommunications
Competing financial interests: The authors declare no competing financial interests.
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reprintsandpermissions/
How to cite this article: Wang, M. et al. The oldest record of ornithuromorpha
from the early cretaceous of China. Nat. Commun. 6:6987 doi: 10.1038/ncomms7987
(2015).
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NATURE COMMUNICATIONS | DOI: 10.1038/ncomms7987 ARTICLE
NATURE COMMUNICATIONS | 6:6987 | DOI: 10.1038/ncomms7987 | www.nature.com/naturecommunications 9
&2015 Macmillan Publishers Limited. All rights reserved.
... In K. mater the hypotarsus is morphologically simple. It lacks proximal vascular foramina, unlike crownward ornithuromorphs, such as hongshanornithids, Patagopteryx deferrariisi, Gansus yumenensis, Iteravis huchzermeyeri, Hollanda luceria, and ornithurines (Bell et al., 2010;Zhou et al., 2014;M. Wang et al., 2015), in which the vascular foramina are well defined. ...
... The oldest record of Ornithuromorpha occurs in the middle Lower Cretaceous (Hauterivian-Barremian) in China (Wang et al., 2015) and roughly coeval beds in Mongolia (O'Connor and Zelenkov, 2013). In contrast, several ornithuromorphs, representing different lineages are recorded in early Aptian Jehol deposits (see Zhou et al., 2003;O'Connor et al., 2011;Wang et al., 2015. ...
... The oldest record of Ornithuromorpha occurs in the middle Lower Cretaceous (Hauterivian-Barremian) in China (Wang et al., 2015) and roughly coeval beds in Mongolia (O'Connor and Zelenkov, 2013). In contrast, several ornithuromorphs, representing different lineages are recorded in early Aptian Jehol deposits (see Zhou et al., 2003;O'Connor et al., 2011;Wang et al., 2015. Recent findings of basal ornithuromorph from coeval beds in Inner Mongolia imply an extended paleogeographic range for the early diversification of Mesozoic birds in eastern Asia (Wang, O'Connor et al., 2020). ...
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The fossil record of Early Cretaceous birds in South America has been restricted to members of Enantiornithes from the Crato Formation (Aptian) of Brazil. Here we describe a new genus and species of bird discovered at Pedra Branca Mine, Nova Olinda County, Ceará State, Brazil, which adds to the avian fossil record from the Crato Formation. The specimen is represented by an isolated foot that is exposed in plantar view. A plantarly displaced metatarsal III with a well-developed hypotarsus supports its referral to Ornithuromorpha, representing the oldest member of the clade reported for Gondwana. Its unique foot conformation indicates that it may belong to an unknown ornithuromorph clade with some cursory similarities to extant flightless ratites. The presence of Early Cretaceous ornithuromorphs in Brazil indicates that the clade was widespread in Gondwana during the Mesozoic. http://zoobank.org/urn:lsid:zoobank.org:pub:08333BA3-F231-4E61-9E89-105C7478AE31
... Longipterygid branches were then grafted onto this tree following the topology of [4] (Shengjingornis, not included in their phylogeny, was assumed to form a polytomy with the [Rapaxavis + Longirostravis] clade as it was recovered sister to the latter in the describing study [13]). We chose to place the Ornithothoraces node at 131 Ma given the age of the oldest known ornithothoracine taxa [119], though the taxa this old are diverse enough that the split likely occurred earlier. The oldest longipterygid, Shanweiniao, is known from the Dawangzhangzi Beds of the Yixian Formation [11], formed approximately 122 Ma [120]. ...
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Background Birds are key indicator species in extant ecosystems, and thus we would expect extinct birds to provide insights into the nature of ancient ecosystems. However, many aspects of extinct bird ecology, particularly their diet, remain obscure. One group of particular interest is the bizarre toothed and long-snouted longipterygid birds. Longipterygidae is the most well-understood family of enantiornithine birds, the dominant birds of the Cretaceous period. However, as with most Mesozoic birds, their diet remains entirely speculative. Results To improve our understanding of longipterygids, we investigated four proxies in extant birds to determine diagnostic traits for birds with a given diet: body mass, claw morphometrics, jaw mechanical advantage, and jaw strength via finite element analysis. Body mass of birds tended to correspond to the size of their main food source, with both carnivores and herbivores splitting into two subsets by mass: invertivores or vertivores for carnivores, and granivores + nectarivores or folivores + frugivores for herbivores. Using claw morphometrics, we successfully distinguished ground birds, non-raptorial perching birds, and raptorial birds from one another. We were unable to replicate past results isolating subtypes of raptorial behaviour. Mechanical advantage was able to distinguish herbivorous diets with particularly high values of functional indices, and so is useful for identifying these specific diets in fossil taxa, but overall did a poor job of reflecting diet. Finite element analysis effectively separated birds with hard and/or tough diets from those eating foods which are neither, though could not distinguish hard and tough diets from one another. We reconstructed each of these proxies in longipterygids as well, and after synthesising the four lines of evidence, we find all members of the family but Shengjingornis (whose diet remains inconclusive) most likely to be invertivores or generalist feeders, with raptorial behaviour likely in Longipteryx and Rapaxavis. Conclusions This study provides a 20% increase in quantitatively supported fossil bird diets, triples the number of diets reconstructed in enantiornithine species, and serves as an important first step in quantitatively investigating the origins of the trophic diversity of living birds. These findings are consistent with past hypotheses that Mesozoic birds occupied low trophic levels.
... O'Connor, 2019;Pittman et al., 2020a)], and so missing information can be preferentially filled by family members. A similar situation is true for the three widely recognised families of non-avian ornithuromorphs [Hesperornithiformes (Clarke, 2004;Bell & Chiappe, 2016), Hongshanornithidae (O'Connor, Gao & Chiappe, 2010a;Wang et al., 2015b;Pittman et al., 2020a), and Songlingornithidae (Hou, 1997;Clarke et al., 2006;Pittman et al., 2020a)]. In addition, the level of error introduced by chimerisation can be estimated by creating similar chimeras of extant bird skulls and comparing results of individuals to that of the composite. ...
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Birds are some of the most diverse organisms on Earth, with species inhabiting a wide variety of niches across every major biome. As such, birds are vital to our understanding of modern ecosystems. Unfortunately, our understanding of the evolutionary history of modern ecosystems is hampered by knowledge gaps in the origin of modern bird diversity and ecosystem ecology. A crucial part of addressing these shortcomings is improving our understanding of the earliest birds, the non‐avian avialans (i.e. non‐crown birds), particularly of their diet. The diet of non‐avian avialans has been a matter of debate, in large part because of the ambiguous qualitative approaches that have been used to reconstruct it. Here we review methods for determining diet in modern and fossil avians (i.e. crown birds) as well as non‐avian theropods, and comment on their usefulness when applied to non‐avian avialans. We use this to propose a set of comparable, quantitative approaches to ascertain fossil bird diet and on this basis provide a consensus of what we currently know about fossil bird diet. While no single approach can precisely predict diet in birds, each can exclude some diets and narrow the dietary possibilities. We recommend combining (i) dental microwear, (ii) landmark‐based muscular reconstruction, (iii) stable isotope geochemistry, (iv) body mass estimations, (v) traditional and/or geometric morphometric analysis, (vi) lever modelling, and (vii) finite element analysis to reconstruct fossil bird diet accurately. Our review provides specific methodologies to implement each approach and discusses complications future researchers should keep in mind. We note that current forms of assessment of dental mesowear, skull traditional morphometrics, geometric morphometrics, and certain stable isotope systems have yet to be proven effective at discerning fossil bird diet. On this basis we report the current state of knowledge of non‐avian avialan diet which remains very incomplete. The ancestral dietary condition in non‐avian avialans remains unclear due to scarce data and contradictory evidence in Archaeopteryx. Among early non‐avian pygostylians, Confuciusornis has finite element analysis and mechanical advantage evidence pointing to herbivory, whilst Sapeornis only has mechanical advantage evidence indicating granivory, agreeing with fossilised ingested material known for this taxon. The enantiornithine ornithothoracine Shenqiornis has mechanical advantage and pedal morphometric evidence pointing to carnivory. In the hongshanornithid ornithuromorph Hongshanornis only mechanical advantage evidence indicates granivory, but this agrees with evidence of gastrolith ingestion in this taxon. Mechanical advantage and ingested fish support carnivory in the songlingornithid ornithuromorph Yanornis. Due to the sparsity of robust dietary assignments, no clear trends in non‐avian avialan dietary evolution have yet emerged. Dietary diversity seems to increase through time, but this is a preservational bias associated with a predominance of data from the Early Cretaceous Jehol Lagerstätte. With this new framework and our synthesis of the current knowledge of non‐avian avialan diet, we expect dietary knowledge and evolutionary trends to become much clearer in the coming years, especially as fossils from other locations and climates are found. This will allow for a deeper and more robust understanding of the role birds played in Mesozoic ecosystems and how this developed into their pivotal role in modern ecosystems. Video abstract
... Unlike China, however, North America does not yet have many localities that produce well-preserved skeletal specimens of Cretaceous birds: skeletal records of birds from the Cretaceous of North America are mostly of fragmentary specimens. Archaeornithura has well-preserved flight feathers with welldeveloped alulae (Wang et al., 2015) and supports the hypothesis that the track-makers responsible for bird tracks from the Lower Cretaceous were volant birds. Also, tracks from volant birds are documented from the Lower Cretaceous Eumeralla Formation (Albian) of Australia: one trackway is interpreted as the tracks of a large wading bird in the process of landing (Martin et al., 2013). ...
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This is the first report of the webbed bird tracks from the middle part of the Jinju Formation (Lower Cretaceous: upper Aptian–lower Albian) in Bito Island, Seopo-myeon, Sacheon City, Gyeongnam, South Korea. Although it is well known that the avian tracks are very abundant and diverse in the Cretaceous Hayang and Yucheon groups of the Gyeongsang Supergroup, bird tracks of the Sindong Group have never been reported. The bird tracks, which are comparatively small (about 3.5 cm length excluding hallux), tetradactyl with a functional reversed hallux, asymmetric and semi-palmate webbing in the hypex between digits II–III and III–IV and are characterized by narrow divarication angle (about 79.8°) between digits II and IV, are described herein as a new ichnotaxon, Ignotornis seoungjoseoi ichnosp. nov. Left and right footprints set showing standing traces is well preserved on the track surface. Tracks of Jindongornipes ichnosp. were also recovered from the intertidal zone of Bito Island, and is the first report of this ichnogenus from the Jinju Formation on Bito Island. The discovery of two ichnotaxa of bird tracks from the Jinju Formation demonstrates that bird diversity from the Lower Cretaceous (upper Aptian–lower Albian) to Upper Cretaceous (Maastrichtian) track record, and the record of terrestrial vertebrate diversity from the Cretaceous Period of Korea, is still in the process of being fully documented and understood.
... All volant and some flightless Mesozoic birds of which the coracoid is known have a cup-shaped cotyla scapularis (Fig. 1d;Clarke 2004;Clarke et al. 2006;Longrich 2009;Wang et al. 2015Wang et al. , 2016Bell and Chiappe 2020), which is likely to be plesiomorphic for Neornithes. However, the coracoscapular joint of extant birds shows much variation, and a cup-shaped cotyla scapularis is replaced by a flat articular facet in many taxa (Fig. 1f). ...
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A survey is given of the morphological variation of the coracoscapular joint of neornithine birds. In Mesozoic stem group representatives, the coracoid exhibits a deeply concave cotyla scapularis, which articulates with a globose tuberculum coracoideum of the scapula. This morphology is likely to be functionally related to the development of a powerful supracoracoideus muscle and the formation of a triosseal canal as a pulley for the tendon of this muscle. In neornithine birds, the coracoid articulates with the scapula either via a concave cotyla or a flat facies articularis, with the latter largely restricting movements of the coracoid to the paramedian plane. Ancestral state reconstruction suggests that a cotyla scapularis is plesiomorphic for Neornithes and that a flat facies articularis scapularis evolved at least 13 times independently within the clade. For several lineages, the transition to a flat facies articularis scapularis can be traced in the fossil record, and the replacement of a cup-shaped cotyla by a flat articular facet seems to have been due to various functional demands. Often, a flat facies articularis scapularis is associated with reduced shafts of the furcula. A weakly developed furcula enables transverse movements of the coracoid and therefore enables a restriction of the mobility of the coracoscapular joint to the paramedian plane. In taxa with a large crop, a flat facies articularis scapularis is likely to be associated with a reorganization of the pectoral musculature, whereas in procellariiform birds, the transition from a cotyla to a facies articularis appears to have been correlated with the capacity for sustained soaring without wing flapping.
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The Early Cretaceous Jehol Biota in northern China is a terrestrial lagerstätte that contains exceptionally-preserved fossils, including birds, dinosaurs, pterosaurs, mammals, insects, and flowering plants. The biota underwent three developmental phases, with relatively limited biodiversity in an early phase that rapidly diversified in a middle phase; however, the relationship between this biological radiation and climate remains uncertain. In this paper, we study fossils from the early-to-middle phases of the Jehol Biota preserved in the Lower Cretaceous (middle Valanginian-lower Barremian) Dabeigou and Dadianzi formations of Hebei Province to ascertain climatic impact on biotic evolution. The occurrence of a cool to warm climate turnover during the deposition of these strata is inferred based on a synthesis of geochemical and paleontological evidence. Palaeogeographic distribution of the middle phase of the biota is wider and positioned more southerly than that of the early phase, possibly indicating that the biota in the early and middle phases lived in boreal and temperate climate realms, respectively. Biotic diversity shows an increasing trend from the early phase to the middle phase of the Jehol Biota, closely coinciding with the cool to warm turnover of the climate. The body sizes of some taxa in the middle phase were significantly smaller than those in the early phase, which is also interpreted as a climatic effect. This study represents the first attempt to correlate the response of terrestrial evolution of the Jehol Biota to climate change, with a focus on Early Cretaceous paleotemperatures.
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The globally distributed extinct clade Enantiornithes comprises the most diverse early radiation of birds in the Mesozoic with species exhibiting a wide range of body sizes, morphologies, and ecologies. The fossil of a new enantiornithine bird, Brevirostruavis macrohyoideus gen. et sp. nov., from the Lower Cretaceous Jiufotang Formation in Liaoning Province, northeastern China, preserves a few important skeletal features previously unknown among early stem and extant birds, including an extremely elongate bony hyoid element (only slightly shorter than the skull), combined with a short cranial rostrum. The long hyoid provides direct evidence for the evolution of specialized feeding in this extinct species, and appears similar to the highly mobile tongue that is mobilized by the paired epibranchials present in living hummingbirds, honeyeaters, and woodpeckers. The likely linkage between food acquisition and tongue protrusion might have been a key factor in the independent evolution of particularly elongate hyobranchials in early birds. The fossil of a new enantiornithine bird, Brevirostruavis macrohyoideus gen. et sp. nov., from the Lower Cretaceous Jiufotang Formation in Liaoning Province, northeastern China, preserves a long hyoid bone that only slightly shorter than the skull. The long hyoid suggests previously unknown specialized feeding in this extinct species and allowed it to utilize a resource that other known birds did not.
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The Valanginian and Hauterivian stages of the Early Cretaceous are an important time interval for the co-evolution of key vertebrate taxa and flowering angiosperm, as well as for the diversification of dinosaurs and early birds on continents. Among these, the Early Cretaceous Jehol Biota in northern China provides the most valuable fossil evidence. Lower Cretaceous terrestrial strata in the Luanping Basin, northern China, is notable for its continuous sedimentary sequence and preservation of the early Jehol Biota, thus providing crucial evidence for probing into terrestrial ecosystem and paleoclimatic change. In this study, we present a chronology for the Lower Cretaceous Dabeigou and Dadianzi formations based on SIMS UPb zircon analyses and previous biostratigraphy and lithostratigraphy from the Zhangjiagou section in the Luanping Basin, northern China. The lowest Dabeigou Formation yields age of 134.1 ± 1.0 Ma, and the upper Dadianzi Formation is constrained to 127.8 Ma, respectively. Previous geochronologic, biostratigraphic studies, and our new geochronology show that the Dabeigou and Dadianzi formations in the Luanping Basin are coeval with the Huajiying Formation in the Sichakou basins, representing the early Jehol Biota evolution, and thus are undoubtedly deposited earlier than the Yixian Formation in western Liaoning. Our findings, combining with the fossil evidence and geochemistry data show that the early evolution of the early stage of the Jehol Biota is constrained to ~132 Ma, characterized by a positive carbon isotope excursion (CIE) and increased biodiversity. The cooler temperature than the underlying sediments attribute to the primary productivity and thus helps the Jehol Biota to thrive.
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Most modern birds have scales covering the foot, while our knowledge of early avian scales is limited, mainly due to the scarcity of fossil record. Here we characterize the morphological details of two types of scales preserved in IVPP V15077, a referred specimen of the Early Cretaceous bird Gansus . The scutellate and interstitial scales, which, in combination with previous discovery of scutate and reticulate scales in other Early Cretaceous birds, indicates that all four types present in modern birds have appeared in the Early Cretaceous. A phylogenetic context of fossilized scales suggests that the evolution of reticulate scales is conservative while that of the other types is more variable. It is consistent with the molecular hypothesis of the scales in modern birds and reptiles that most integumentary structures in amniotes are homologous with modified signaling modules to form various integumentary phenotypes, among which the reticulate scales may use the conserved signaling pathway.
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A new genus and species of a basal ornithurine bird is reported from the Lower Cretaceous Jiufotang Formation of Jianchang, Liaoning, China. It is represented by a nearly complete articulated skeleton of a sub-adult individual. It is distinguishable from other known ornithurines by possessing a combination of features including at least 16 small and conical teeth on the dentary, scapula strongly curved, metacarpal I robust and wider than other metacarpals, first manual digit long and extending beyond distal metacarpal II, and length ratio of humerus+ulna+metacarpal II to femur+tibiotarsus+tarsometatarsus is approximately 1.1. Phylogenetic analysis indicates that the the new taxon is a basal ornithurine. Jianchangornis represents the second Early Cretaceous bird with the preservation of a predentary bone, which may further confirm that a predentary could be a feature common to Mesozoic ornithurines. The advanced features of the pectoral girdle, sternum and wings of the new bird indicate its powerful flight capability, and the hindlimb bone and toe proportions as well as the ungual morphology suggest a terrestrial locomotion similar to those of Yanornis and Yixianornis. The associated fish fragments may indicate a piscivorous diet consistent with the dentation of the new bird. The discovery of a new basal ornithurine further shows that the diversification of the Ornithurae is probably no less than the enantiornithes, and the near lakeshore adaptation had definitely played a key role in the early ornithurine radiation.
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A new genus and species (Parahongshanornis chaoyangensis) of a basal ornithurine bird from the Jiufotang Formation in Yuanjiawa Town, Chaoyang, western Liaoning Province is reported. It is morphologically most similar to the basal ornithurines Hongshanornis and Longicrusavis, two only known genera of the Hongshanornithidae by possessing a shorter wing compared to the leg and a “U”-shaped furcula that is significantly longer than wide. The new taxon can be distinguished from these two genera in having a furcula that is anteroposteriorly compressed proximally, with a deep groove along the clavicular symphysis, a sternum with two pairs of posterior excavations, and a pair of short posterior processes between the lateral trabecula and the medial ridge of the sternum, a short and robust first phalanx of the major digit, and a pubis with a distinctive pubic foot. The discovery of the new hongshanornithid from the Jiufotang Formation not only extends the temporal distribution of the Hongshanornithidae, but also provides new data for discussing the evolutionary differentiation of basal ornithurines in the Early Cretaceous.
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We report a new species of basal ornithurine bird, Schizooura lii gen. et sp. nov., based on a well-preserved specimen from the Lower Cretaceous Jiufotang Formation in Jianchang, western Liaoning, China. Phylogenetic analysis indicates that it is more derived than Jianchangornis and Archaeorhynchus, but more basal than all other known Jehol ornithurines. The new specimen preserves a unique suite of characters that differentiate it from other known taxa, including several features previously unreported in Early Cretaceous ornithurines, including a V-shaped furcula with a short hypocleidium, a rostrocaudally elongate unperforated sternum with deep caudal notches absent, and a deltopectoral crest that extends for half the length of the humerus. The specimen preserves a nearly perfectly articulated skull that indicates the species was beaked and preserves details of the skull anatomy such as the premaxilla-frontal articulation. The most notable feature of this new specimen is the preservation of a feathered tail morphology previously unknown among Mesozoic birds. It is the second tail morphology known among early ornithurines, which have until now only preserved fan-shaped tails. The new specimen preserves a forked tail composed of elongate rectrices medially separated by a deep notch. This tail feather morphology in modern birds decreases aerodynamic efficiency relative to the fan-shaped tail, but increases chance of sexual reproduction. This discovery suggests that this tradeoff convergently evolved in basal members of Ornithurae, and is consistent with the wooded environment inferred for the Jehol.
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We report on a new species of basal ornithuromorph bird, Tianyuornis cheni gen. et sp. nov., based on a nearly complete and articulated subadult individual from the Lower Cretaceous Yixian Formation in the eastern region of Nei Mongol, China. The new specimen shows features characteristic of the Hongshanornithidae (Hongshanornis longicresta, Longicrusavis houi, and Parahongshanornis chaoyangensis), such as small body size and elongate hindlimbs relative to their forelimbs, but it also possesses some unique features that support the erection of a new genus and species, including a straight dentary (a sigmoidal dentary was previously considered an autapomorphy of hongshanornithids), teeth preserved on both the upper and lower jaws, sternal caudolateral trabecula has a distinct fan-shaped expanded distal end. With the addition of this new taxon, Hongshanornithidae represents the most diverse recognized clade of Early Cretaceous ornithuromorphs. The new specimen reveals new important morphological information regarding the Hongshanornithidae and confirms the controversial presence of teeth in this clade.
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We report on a new species of basal ornithuromorph bird, Piscivoravis lii gen. et sp. nov., based on a well-preserved and nearly complete specimen from the Lower Cretaceous Jiufotang Formation in western Liaoning Province, northeastern China. The new specimen preserves several unique anatomical features previously unreported in Early Cretaceous ornithuromorphs, such as a robust furcula with strongly tapered omal tips, a broad sternum without craniocaudal elongation and large and strongly curved manual unguals. Phylogenetic analysis indicates that Piscivoravis is more derived than Archaeorynchus, but in a basal polytomy with Jianchangornis, Patagopteryx, and the clade including all more derived ornithuromorphs. The preserved wing and tail feathers provide new information on feather diversity and evolution in Early Cretaceous ornithuromorphs. The preservation of fish bones ventral to the dentary and in the stomach provides direct evidence that the new species was piscivorous – previously only reported in Yanornis, and as in some living birds, was capable of moving food bidirectionally through the alimentary canal.http://www.zoobank.org/urn:lsid:zoobank.org:pub:92F23126-9E89-4E51-9700-C6608E0D66EB
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Discoveries of bird-like theropod dinosaurs and basal avialans in recent decades have helped to put the iconic 'Urvogel' Archaeopteryx into context and have yielded important new data on the origin and early evolution of feathers. However, the biological context under which pennaceous feathers evolved is still debated. Here we describe a new specimen of Archaeopteryx with extensive feather preservation, not only on the wings and tail, but also on the body and legs. The new specimen shows that the entire body was covered in pennaceous feathers, and that the hindlimbs had long, symmetrical feathers along the tibiotarsus but short feathers on the tarsometatarsus. Furthermore, the wing plumage demonstrates that several recent interpretations are problematic. An analysis of the phylogenetic distribution of pennaceous feathers on the tail, hindlimb and arms of advanced maniraptorans and basal avialans strongly indicates that these structures evolved in a functional context other than flight, most probably in relation to display, as suggested by some previous studies. Pennaceous feathers thus represented an exaptation and were later, in several lineages and following different patterns, recruited for aerodynamic functions. This indicates that the origin of flight in avialans was more complex than previously thought and might have involved several convergent achievements of aerial abilities.
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— We studied sequence variation in 16S rDNA in 204 individuals from 37 populations of the land snail Candidula unifasciata (Poiret 1801) across the core species range in France, Switzerland, and Germany. Phylogeographic, nested clade, and coalescence analyses were used to elucidate the species evolutionary history. The study revealed the presence of two major evolutionary lineages that evolved in separate refuges in southeast France as result of previous fragmentation during the Pleistocene. Applying a recent extension of the nested clade analysis (Templeton 2001), we inferred that range expansions along river valleys in independent corridors to the north led eventually to a secondary contact zone of the major clades around the Geneva Basin. There is evidence supporting the idea that the formation of the secondary contact zone and the colonization of Germany might be postglacial events. The phylogeographic history inferred for C. unifasciata differs from general biogeographic patterns of postglacial colonization previously identified for other taxa, and it might represent a common model for species with restricted dispersal.
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We report on a new enantiornithine Eopengornis martini gen. et sp. nov. from the lowest horizon of the Jehol Biota in Hebei, China; dated at 130.7 Mya, this is the second oldest avian bearing fossil deposit in the world, recording the First Appearance Datum of Enantiornithes. The new specimen, only the second enantiornithine and third bird reported from this horizon, preserves numerous synapomorphies with the largest Lower Cretaceous enantiornithine Pengornis houi from the Jiufotang Formation dated at 120 Mya. Together, they form a new avian lineage that lasted over 10 Myr, which is longer than any known clade of Lower Cretaceous enantiornithine. Eopengornis reveals new information about basal enantiornithine morphology such as the presence of a metatarsal V, helping to clarify the early evolution of these dominant Cretaceous avians. Furthermore, Eopengornis preserves a previously unrecognized tail morphology: a pair of elongate fully pennaceous rachis dominated feathers. This discovery confirms hypotheses proposing that the rachis dominated racket-plumes in basal birds represent modified pennaceous feathers. We suggest that the ornamental racket-plumes in enantiornithines and Confuciusornis evolved independently from the basal pygostylian condition, which we infer was a tail formed of normal flight feathers. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 805–819.
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The main features of the phylogeny program TNT are discussed. Windows versions have a menu interface, while Macintosh and Linux versions are command-driven. The program can analyze data sets with discrete (additive, non-additive, step-matrix) as well as continuous ...