Nurhachius luei: A new species of Istiodactylid Pterosaur from the Early Cretaceous Jiufotang Formation of Liaoning Province, China.

The Pterosaurs were an extinct group of flying Archosaurs that existed from the late Triassic to the end of the Cretaceous Period (210 to 65.5 million years ago). They are thought to have been warm blooded, as  many specimens have been found that appear to have had fury skins. Their wings were flaps of skin membrane, similar to that of Bats, supported by elongated fourth fingers and attached to the flanks of the body and legs. Unlike Birds they appear to have been capable of flying before reaching their full adult size, and appear to have taken several years to reach maturity. The largest Pterosaurs achieved wingspans in excess of 7 m, roughly twice that of the largest extant Birds. Despite their long history and high diversity, the fossil record of Pterosaurs is somewhat limited, probably due to their lightweight, fragile skeletons, with most known Pterosaur fossils coming from a relatively small number of localities. Istiodactylid Pterosaurs are characterised by rhombic teeth with lancet-shaped crowns, long skulls with short pre-antorbital portions of the rostrum (long snout in front of the opening before the eye), and nasoantorbital fenestrae (opening on the snout in front of the eye) representing over 50% of the total skull length and height. All istiodactylid pterosaurs are from the Early Cretaceous Jiufotang Formation of northeastern China with the exception of Istiodactylus latidens, which is from the Early Cretaceous Vectis Formation of the Isle of Wight, Southern England.

In a paper published in the journal PeerJ on 19 September 2019, Xuanyu Zhou of the Institute of Geology of the Chinese Academy of Geological Sciences, and the China University of Geosciences, Rodrigo Pêgas of the Laboratory of Vertebrate Paleontology and Animal Behavior at the Universidade Federal do ABC, Maria Leal of the Departamento de Geologia at the Universidade Federal do Ceará, and the Zoological Museum at Copenhagen University, and Niels Bonde, also of the Zoological Museum at Copenhagen University, and of the Fur Museum, describe a new species of Istiodactylid Pterosaur from the Early Cretaceous Jiufotang Formation of Liaoning Province, China.

The Jiufotang Formation is known worldwide for its paleontological richness and the exquisite preservation of its fossils, which include Plants, Insects, Fish, Mammal, Birds, non-Avian Dinosaurs, and Pterosaurs. The formation is 206–2685 m thick and is mainly composed of mudstone, siltstone, shale, sandstone and tuff. A tuff (volcanic ash horizon) from the basal part of formation (two metres above the boundary between the Yixian and Jiufotang formations) in western Liaoning has been dated to 122.1 million years ago, while a basalt layer in the upper part of the formation in Inner Mongolia has been dated to 110.59 million years ago, though it is unclear how well this correlates to the upper part of the formation in Liaoning. The Jiufotang Formation and the underlying Yixian Formation traditionally constitute the Jehol Group, which has yielded the famous Jehol Biota. Four fossil-bearing levels with partly different fossil associations have been distinct within the Yixian Formation and only one in the Jiufotang Formation.

The new Pterosaur species is placed in the genus Nurhachius, which currently contains only one species, Nurhachius ignaciobritoi, also from the Jiufotang Formation, and is given the specific name luei, in honour of the late Junchang Lü, of the Institute of Geology of the Chinese Academy of Geological Sciences, for his contributions to the study of Chinese Pterosaurs. Nurhachius luei is described from a single specimen comprising a skull with mandible and seven articulated cervical vertebrae.

Nurhachius luei, photograph, and line drawing. The scale bar in the line drawing equals 50 mm. Abbreviations: alv, alveolus; an, angular; art, articular; ax, axis; ceI, ceratobranchial I; ch, choana; cv, cervical vertebra; d, dentary; f, frontal; j, jugal; la, lacrimal; m, maxilla; n, nasal; naof, nasoantorbital fenestra; odp, odontoid process; or, orbit; pa, parietal; pf, prefrontal; pmax, premaxilla; po, postorbital; prid, palatal ridge; pty, pterygoid; q, quadrate; vo, vomer. Isolated numbers indicate tooth positions. Note: the visible region of the pterygoid corresponds to the medial process of the bone. Photo by Xuanyu Zhou, drawing by Maria Eduarda Leal. Zhou et al. (2019).

The skull of Nurhachius luei is exposed in right lateral view, with some palatal elements that are visible in dorsal view. The mandible is exposed in right dorsolateral view. The skull is 300 mm long from the squamosal to the premaxillary tip (total skull length), and 74 mm high at its greatest height, which is at the level of the occiput. The nasoantorbital fenestra is long, corresponding to 45% of the total skull length (premaxilla to squamosal) and 55% of the length from the craniomandibular joint to the premaxilla. Anterior to the nasoantorbital fenestra, the long axis of the rostrum is slightly deflected dorsally, as in other Istiodactylids. There is a strong palatal keel extending from pre-narial part of the rostrum to the anterior third of the nasoantorbital fenestra. The craniomandibular joint levels with the anterior margin of the orbit.

The premaxilla is fused with the maxilla and the suture is obliterated, thus the boundary between the two bones cannot be traced. Consequently, the premaxillary and maxillary teeth count is unknown. There is no premaxillary crest, as in all other Istiodactylids. The rostral tip of the premaxilla exhibits a slight dorsal deflection of palatal anterior tip, as evidenced from the uplifted positions of the two anteriormost teeth.

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Versperopterylus lamadongensis: A new species of Anurognathid Pterosaur from the Early Cretaceous of Liaoning Province, China.

The Anurognathid Pterosaurs are small, short-tailed Pterosaurs known from the Jurassic of Asia, Europe, and possibly North America. They has proportionally large eye-sockets, which has been taken as evidence of a nocturnal or crepuscular lifestyle, and spaced, pointed teeth, suitable for catching Insects or possibly Fish, which has led to suggestions that they may have had a lifestyle similar to that of modern Bats.

In a paper published in the Geological Society London Special Publications on 8 September 2017, Junchang Lü of the Institute of Geology of the Chinese Academy of Geological Sciences, and the Key Laboratory of Stratigraphy and Palaeontology of the Ministry of Land and Resources of China, Qingjin Meng, Baopeng Wang and Di Liu of the Beijing Museum of Natural History, Caizhi Shen, also of the Institute of Geology of the Chinese Academy of Geological Sciences, and the Key Laboratory of Stratigraphy and Palaeontology of the Ministry of Land and Resources of China, and Yuguang Zhang, also of the Beijing Museum of Natural History, describe a new species of Anurognathid Pterosaur from the Early Cretaceous Jiufotang Formation of Jianchang County in Liaoning Province, China (part of the Jehol Biota).

The new species is named Versperopterylus lamadongensis, where 'Versperopterylus' means 'Dusk-wing', in reference to the presumed Bat-like habits of Anurognathid Pterosaurs, and 'lamadongensis' means 'from Lamadong', in reference to the location where the specimen was found. The species is described from a single specimen, preserved on a slab, which is partially disarticulated, but almost complete, lacking only one humerus, some fingers from the left hand and some cervical (neck) vertebrae.

Photograph (a) and line drawings (b) of Versperopterylus. Abbreviations: cav, caudal vertebrae; csk, crushed skull; co, coracoids; dv, dorsal vertebrae; dr, dorsal ribs; f, femur; fot, fourth toe; fi, fibula; ft, first toe; h,, humerus; lj, lower jaw; mc, maniual claw; mcI-IV, metacarpals I–IV; mttI-IV, metatarsals I–IV; mttv, metatarsal V; pt, pteroid; rd, radius; sc, scapula; ti, tibia; ul, ulna. Lü et al. (2017).

The specimen is estimated to have had a wing-span of about a metre. It had an exceptionally small skull, which was wider than it was long, though this is somewhat crushed, obscuring any detail. The upper jaw appears to have had about 12 teeth. One of its toes appears to have been reversed in life, which is likely to have been an adaptation for gripping, which in turn strongly suggests an arboreal (tree-dwelling) life-style.

Artists interpretation of Versperopterylus as a living animal. Zhao Chuang in Lü et al. (2017).

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Preserved plumage in an immature Bohaiornithid Bird from the Jehol Biota.

The Bohaiornithids were an early group of Enantiornithine Birds (a group of Toothed Birds dominant in many Cretaceous faunas; the modern Euornithine Birds having come to prominence only after the End Cretaceous Extinction). The Bohaiornithids are known from the Jiufotang and Yixian Formations, together the Jehol Biota, giving them a chronological range from 125 to 120 million years ago.

In a paper published in the journal Palaeontology on 13 November 2016, Jennifer Peteya of the Department of Biology and Integrated Bioscience Program at the University of Akron, Julia Clarke of the Department of Geological Sciences at the University of Texas at Austin, Quangou Li of the State Key Laboratory of Biogeology and Environmental Geology at the China University of Geosciences, Ke-Qin Gao of the School of Earth and Space Sciences at Peking University and Matthew Shawkey, also of the Department of Biology and Integrated Bioscience Program at the University of Akron and of the Terrestrial Ecology Unit at the University of Ghent describe a new Bohaiornithid specimen with well preserved plumage from the Early Cretaceous Jiufotang Formation of Liaoning Province in northeastern China.

The new specimen is adjudged to be a subadult based upon the development of its skeleton. It does not appear to be a member of any previously described species of Bohaiornithid, but since the ontogeny (development) of these Birds is not well understood, Peteya et al. refrain from describing it as a member of a new species. However despite lacking a fully mature skeleton, the specimen appears to have full adult plumage; this is different to the situation in modern Birds, which do not gain their full adult plumage, or ability to fly, until they are fully mature.

Ventral view of the new Bohaiornithid specimen. (A) Photograph of the primary slab. (B) Interpretive drawing. Abbreviations: co, coracoid; cv, cervical vertebrae; fe, femur; fu, furcula; hu, humerus; il, ilium; mcI–III, metacarpals I–III; mt, metatarsals; pd I–IV, pedal digits I–IV; phI-1, first phalanx of digit I; phII/III-1/2, first/second phalanx of digit II/III; pu, pubis; py, pygostyle; ra, radius; sc, scapula; sk, skull; sml, semilunate carpal; st, sternum; sy, synsacrum; th, thoracic vertebrae; ti, tibia; ul, ulna; uln, ulnare. Scale bar represents 1 cm. Peteya et al. (2016).

Close examination of the plumage of the specimen revealed the presence of preserved melanosomes (pigment bearing-cells). When these cells were analysed using Raman spectroscopy, suggested that three different types of melanosomes were present, associated with black, brown and iridescent colouring. While it was not possible to tell the colour of the iridescent plumage was impossible to tell, but the presence of iridescent colouring in a Bird that was not fully grown is interesting. In modern Birds the presence of iridescent plumage is always associated with sexual maturity, often coming some time after the Bird reaches physical maturity. If the iridescent feathers of the Jehol Bird are also associated with sexual maturity, then it implies that this Bird reached sexual maturity before it was fully grown. This is completely different from the situation seen in modern Birds, but is similar to that seen in their closest living relatives (and the only other surviving Archosaur group) the Crocodylians, in which sexual maturity is reached long before full size is achieved.

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Chongmingia zhengi: A new species of Bird from the Early Cretaceous Jehol Biota of Liaoning Province, China.

The earliest Bird known in the fossil record is Archaeopteryx lithographica from the Late Jurassic Solnhofen Limestone of Germany, after which no further Birds are known until the Early Cretaceous Jehol Biota of northeastern China (and possibly North Korea), where numerous Bird specimens have been found, including members of the Enantiornithes (the most abundent group of Birds in the Cretaceous fossil record) and Ornithuromorpha (the group that includes all modern Birds), as well as distinctive groups such as the Jeholornithiformes, Sapeornithiformes and Confuciusornithiformes not known from as other deposits.

In a paper published in the journal Scientific Reports on 25 January 2016, Min Wang of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and the State Key Laboratory of Palaeobiology and Stratigraphy at the Nanjing Institute of Geology and Palaeontology, Xiaoli Wang and Yan Wang of the Institute of Geology and Paleontology at Linyi University and the Shandong Tianyu Museum of Nature and Zhonghe Zhou, again of the Key Laboratory of Vertebrate Evolution and Human Origins, describe a new species of early Bird from the Jiufotang Formation of Liaoning Province, one of the deposits considered to make up the Jehol Biota.

The new species is named Chongmingia zhengi, where Chongmingia refers to Chongming, a mythical Bird from ancient China, and zhengi honours Xiaoting Zheng for his contributions to the founding of the Shandong Tianyu Museum of Nature. The species is described from a single partial skeleton, with some associated soft tissue and feathers, but lacking the head and tail. 

Photograph and line drawing of Chongmingia zhengi. Abbreviations: ad-1, proximal phalanx of the alular digit; am, alular metacarpal; ca, caudal vertebra; cm, carpometacarpus; cv, cervical vertebra; fe, femur; fu, furcula; ga, gastralia; gs, gastroliths; hu, humerus; md-1, 2, phalanx 1, 2 of the major digit; mtI, metatarsal I; mtV, metatarsal V; pd, pedal digit; pu, pubis; ra, radius; rad, radiale; sc, scapulocoracoid; sy, synsacrum; ti, tibiotarsus; tm, tarsometatarsus; ul, ulna; uln, ulnare; l/r, left or right side. Scale bars are 50 mm. Min Wang in Wang et al. (2016).

Chongmingia zhengi shows a number of unique features not seen in any other early Bird including a robust fercula (wishbone) with an unusually sharp angle and a coracoid and scapula fused together into a single bone, the scapulocoracoid. A scapulacoracoid is also found in a wide range of non-Avian Dinosaurs, including groups closely related to Birds, such as Dromeosaurs and Oviraptors, as well as in some Amphibians, Pterosaurs and modern Ratite Birds (Ostriches, Emus etc.). The presence of a scapulacoracoid in flightless Birds and close Bird relatives might suggest that it is not a good adaptation for flight, however Pterosaurs are thought to have been powerful fliers, and the structure of the scapulacoracoid in Chongmingia zhengi is quite different to that seen in Ratites, with the bones fused at approximately right angles tather than roughly parallel, suggesting that Chongmingia zhengi rather than being a weak flier, may have achieved flight with a unique set of adaptations.

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Preserved feathers in an Enantiornithine Bird from the Early Cretaceous Crato Formation of Brazil.                                                    While feathers have been known in fossil Birds...

Preserved stomach contents in Early Cretaceous Ornithuromorph Birds.                     The Early Cretaceous Jehol Group of China has produced a remarkable number of well-preserved fossils of Mesozoic Birds, adding greatly to our understanding of the early history of this group...

Two new species on Enantiornithine Birds from the Jehol Biota.                                   The deposits of the Jehol Group in northeastern China have yielded a spectacular number of fossil Birds and closely related non-Avian Theropod Dinosaurs over...

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A new specimen of Microraptor from western Liaoning Province, China.

In December 2000 Xing Xu, Zonghe Zhou and Xioalin Wang of the Institute of Vertebrate Paleontologyand Paleoanthropology of the Chinese Academy of Sciences described a new species of Dromaeosaurid from the Early Cretaceous Jiufotang Formation of western Liaoning Province in a paper in the journal Nature. This was the smallest non-Avian Dinosaur ever found, and showed a remarkable similarity to the earliest Birds, including an extensive covering of feathers.

This Dinosaur was named Microraptor zhaoianus, and since this time a number of further specimens of Microraptor have been discovered and two further species have been described (though these are not universally accepted). Remarkably the new specimens have revealed further Bird-like features, including the presence of two pairs of wings (unlike in Birds, the hindlimbs of Microraptor were also modified for flight).

In a paper published in the American Museum Novitates on 22 December 2014, Rui Pei of the Division of Paleontology at the American Museum of NaturalHistory, Quangou Li of the State Key Laboratory of Biogeology and Environmental Geology at the China University of Geosciences, Qingjing Meng of the BeijingMuseum of Natural History, Ke-Qin Gao of the School of Earth and Space Sciences at Peking University and Mark Norell, also of the Division of Paleontology at the American Museum of Natural History, describe a new specimen of Microraptor zhaoianus from the same deposits as the original (and all subsequent) specimens.

The new specimen of Microraptor zhaoianus, view of entire mounted slab. Pei et al. (2014).

The new specimen is exceptionally well preserved, possessing a number of features not seen in other specimens. It shows several traits previously described that clearly mark Microraptor out as a Dromaeosaur, including extremely elongate prezygapophyses and chevrons (re-enforcing structures that help support the rigid tail in Dinosaurs – check), a vertical process on the posteromedial corner of the retroarticular process of the mandible and a reduced manual phalanx III-2, and in addition another Dromaeosaur trait not seen in any previously described specimen, dorsal displacement of the maxillary fenestra and a large quadrate foramen.

Skull and mandible of the new specimen of Microraptor zhaoianus, photograph (top) and interpretive drawing (bottom). Abbreviations: aof, antorbitalfenestra; emf, external mandibularfenestra; hy, hyoid; j, jugal; l, lacrimal; lan, left angular; lar, left articular; ld, left dentary; lfr, left frontal; lsp, left splenial; m, maxilla; mf, maxillary fenestra; n, nasal; na, naris; pa, parietal; pm, premaxilla; po, postorbital; pra, prearticular; q, quadrate; qj, quadratojugal; ran, right angular; rar, right articular; rfr, right frontal; sa, surangular; sq, squamosal. Pei et al. (2014).

The new specimen also shows a number of features in common with early Troodontids which have been reported in other specimens, such as a short subnarial process on the premaxilla, smaller teeth on the premaxilla than on the maxilla, no denticles on the anterior carinae of the maxillary teeth and a Troodontid-like articulation of the foot. In addition this specimen has a better-preserved maxilla and face than previous specimens, showing other Troodontid-like features, such as a shallow main body of the bone and a slender interfenestral bar combined with an enlarged maxillary fenestra. This supports the close relationship of the Dromaeosaurs and Troodontids previously proposed; the two are currently grouped together to form the Deinonychosauria, to the exclusion of other Maniraptors, including the Birds.

However the arrangement of the rib-cage in the new specimen is probably its most remarkable feature, this preserves gastralia and uncinate processes, features known from a variety of Theropod Dinosaurs including other Dromeaosaurs, but in this case remarkably similar to those of the early Bird Confuciusornis. This suggests that respiration in Microraptorwas similar to that in early Birds, lending further weight to the idea that it could also fly.

The rib cage of the new specimen of Microraptor zhaoianus. Abbreviations: dr, dorsal rib; h, humerus; lms, left medial segment of gastralia; rls, right lateral segment of gastralia; rms, right medial segment of gastralia; sc, scapular; st, sternum; up, uncinate process. Pei et al. (2014).

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New species of Dromaeosaur from the Early Cretaceous of Utah.                                        Dromaeosaurs were small Therapod Dinosaurs, thought to have been the group most closely related to...

Dinosaur footprints from the Early Cretaceous of Ganzu Province, China.            The Deinonychosaurs are the group of dinosaurs most closely related to the birds. They are divided into two groups, the Dromaeosaurs (popularly known as 'Raptors') and the Troodontids, which share a common hindlimb morphology, with two digits used to support...

How did raptors use their claws? (and did it help them learn to fly?)                                                      The Dromaeosaurs were a group of small, feathered dinosaurs closely related to the birds. They are commonly referred to as 'raptors' on account of an enlarged claw on each foot which was held clear of the ground when walking and is generally assumed to have been a weapon; this claw resembles that of a bird of prey, which are also referred to as 'raptors'. This claw was also present in the other group...

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Two new species on Enantiornithine Birds from the Jehol Biota.

The deposits of the Jehol Group in northeastern China have yielded a spectacular number of fossil Birds and closely related non-Avian Theropod Dinosaurs over the past three decades. The most numerous and diverse group of Birds in this assemblage are the Enantiornithines, toothed Birds related but not ancestral to the modern Neornithine Birds, with about 27 separate species described from numerous specimens. 

In a paper published in the journal Vertebrata PalAsiatica on 21 January 2014, Wang Min of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and the University of Chinese Academy of Sciences, Zhou Zhong-He and Jingmai O’Connor, also of the Key Laboratory of Vertebrate Evolution and Human Origins and Nikita Zelenkov of the Borissiak Palaeontological Institute of the Russian Academy of Sciences describe two new species of Enantiornithine Birds from the Jehol Biota.

The first new Bird species is named Parabohaiornis martini, where ‘Parabohaiornis’ means ‘similar to Bohaiornis’ (a previously described species of Enantiornithine Bird) and ‘martini’ honours the late Larry Martin, a distinguished palaeontologist and expert on avian evolution. Parabohaiornis martini is described from two specimens, from the Jiufotang Formation at Lamadong in Jianchang County in Liaoning Province.

The first specimen of Parabohaiornis martini is complete and partially articulated, and appears to be from a subadult, as not all the bones are fully fused. The second appears to be from a fully mature individual, but lacks the head and the wings below the elbow joint.

Photograph and line drawing of Parabohaiornis martini. Abbreviations: alm. alular metacarpal; al 1, 2. alular digit phalanx 1, 2; cav. caudal vertebrae; co. coracoid; cv. cervical vertebrae; dr. dorsal rib; dt. distal tarsal; fe. femur; fi. fibula; fu. furcula; ga. gastralia; hu. humerus; il. ilium; is. ischium; ma 1, 2, 3. major digit phalanx 1, 2, 3; mam. major metacarpal; mi 1. minor digit phalanx 1; mim. minor metacarpal; mt I–IV. metatarsal I, II, III, IV; pd. pedal digits; pt. proximal tarsals; pu. pubis; py. pygostyle; r. radius; ra. radiale; sc. scapula; sem. semilunate carpal; sk. skull; sr. sternal rib; st. sternum; sy. synsacrum; ti. tibia; tv. thoracic vertebrae; u. ulna; ul. ulnare. Wang et al. (2014).

Parabohaiornis martini is a medium sized, robust Enantiornithine Bird with three robust conical teeth on each premaxilla and four more on each maxilla. 

Photograph and line drawing of the second specimen of Parabohaiornis martini. Abbreviation: fv. vertebrae of fish; other abbreviations follow the top image. Wang et al. (2014).

The second new species is named Longusunguis kurochkini, where ‘Longusunguis’ means ‘long-claw’ and ‘kurochkini’ honours the late Evgeny Kurochkin, a distinguished palaeontologist and expert on fossil Birds. Longusunguis kurochkini is described from a single specimen, again from the Jiufotang Formation at Lamadong. The specimen is complete and articulated, though the head is detached. It also appears to be a subadult.

Longusunguis kurochkini is a medium-sized Enantiornithine Bird with robust conical teeth and long, curved claws.

Photograph and line drawing of Longusunguis kurochkini. Abbreviations: par. parapophyses; pot. posterior trochanter; other abbreviations follow the top image. Wang et al. (2014).

Parabohaiornis martini and Longusunguis kurochkini appear to be closely related, as well as also being closely related to the previously described Bohaiornis, Shenqiornis, Sulcavis and Zhouornis. Wang et al. suggest that these Birds should be grouped together to form a separate family within the Enantiornithine, which they name as the Bohaiornithidae.

All members of the Bohaiornithidae appear quite similar, being roughly medium sized (for Enantiornithine Birds), robust conical teeth and strong feet with long, curved claws. This suggests that they occupied a distinct ecological niche, though the exact nature of this was impossible to determine. 

The tough elongate feet of the Bohaiornithidae are typical of ground-living Birds today, but this seems unlikely due to their curved claws. Claws like those seen in the Bohaiornithidae are seen in the modern Raptors, as well as in Birds that habitually climb of tree-trunks. However tree-trunk climbing Birds typically have a number of specialized features on their hindlimbs, none of which are present in the Bohaiornithidae. Nor do they appear well suited for hunting like Raptors, as the proportions of their feet are quite different, and their teeth appear adapted for a durophagous diet.

See also…

 A subadult Enantiornithine Bird from the Early Cretaceous Jiufotang Formation of western Liaoning Province.

The dominant group of Birds during much of the Cretaceous Period were the Enatiornithine, toothed Birds related, but not ancestral, to modern Birds. The largest known species of Enatiornithine from the...

 Preserved ovarian follicles in Mesozoic Birds.

The two surviving groups of Archosaurs, Crocodilians and Birds, show very different reproductive strategies.  Crocodilians have paired ovaries and produce large clutches of small eggs, which mature slowly prior to being laid, and make a relatively small investment in parental care. Birds have only a single ovary, a modification not seen in any other Amniote (Reptile or Mammal) with eggs...

 An Enatiornithine Bird from the Early Cretaceous Jehol Biota.

Birds derived from small Theropod Dinosaur ancestors in the Middle Jurassic, and appear to have reached similar levels of diversity in the Cretaceous to that seen today. However the dominant group of Birds in the Cretaceous were the Enatiornithines, a group of toothed Birds related to but not ancestral to modern Birds (Ornithuromorpha), which died out...

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A subadult Enantiornithine Bird from the Early Cretaceous Jiufotang Formation of western Liaoning Province.

The dominant group of Birds during much of the Cretaceous Period were the Enatiornithine, toothed Birds related, but not ancestral, to modern Birds. The largest known species of Enatiornithine from the Early Cretaceous is Pengornis houi, described from a single specimen from the Jiufotang Formation of northern China, part of the Jehol Biota.

In a paper published in the journal Vertebrata PalAsiatica on 21 January 2014, Hu Han of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and the University of the Chinese Academy of Sciences and Zhou Zhong-He and Jingmai O'Conner, also of the Key Laboratory of Vertebrate Evolution and Human Origins, describe a second specimen of Pengornis from the Early Cretaceous Jiufotang Formation of western Liaoning Province.

The new specimen is an almost complete articulated skeleton with some feathers intact. It shows strong similarities to Pengornis houi, but is also different enough that were it a second adult specimen, then it would probably be placed within a separate species within the same genus. However, since it is not a completely mature specimen it cannot be confidently asserted that it is a new species either. For this reason it is placed in the genus Pengornis, but not assigned to species level.

Photo of the subadult specimen of Pengornis sp. Hu et al. (2014).

Camera lucida drawing of the subadult specimen of Pengornis sp. 

Abbreviations: as. astragalus; ca. calcaneum; ce. cervical vertebrae; co. coracoid; cv. 

caudal vertebrae; dr. dorsal rib; fe. femur; fi. fibula; ft. feathers; fu. furcula; 

ga. gastralia; hu. humerus; il. ilium; is. ischium; mcI-III. metacarpals I-III

; md. manual digits; mtI-V. metatarsals I-V; pd. pedal digits; pu. pubis; 

py. pygostyle; r. radius; ra. radiale; sc. scapula; se. semilunate carpal

; sk. skull; sr. sternal rib; st. sternum; sy. synsacrum; ti. tibia; tv. thoracic 

vertebrae; u. ulna; ul. ulnare; up. uncinate process. 

Hu et al. (2014).

See also...

 Preserved ovarian follicles in Mesozoic Birds.

The two surviving groups of Archosaurs, Crocodilians and Birds, show very different reproductive strategies.  Crocodilians have paired ovaries and produce large clutches of small eggs, which mature slowly prior to being laid, and make a relatively small investment in parental care. Birds have only a single ovary, a modification not seen in any other Amniote (Reptile or Mammal) with eggs that mature rapidly prior to being laid, smaller clutch sizes and larger eggs, and make a higher level of...

 An Enatiornithine Bird from the Early Cretaceous Jehol Biota.

Birds derived from small Theropod Dinosaur ancestors in the Middle Jurassic, and appear to have reached similar levels of diversity in the Cretaceous to that seen today. However the dominant group of Birds in the Cretaceous were the Enatiornithines, a group of toothed Birds related to but not ancestral to modern Birds (Ornithuromorpha), which died out in the end Cretaceous extinction event.

 A new Long-tailed Bird from the Early Cretaceous of China.

Discovered in the 1860s, Archaeopteryx had a unique combination of features, including a long, feathery tail, that marked it out as distinctive, intermediate between a Dinosaur and a Bird, which sealed Archaeopteryx's status as the First Bird. While it remained unique in this way for a lone time, recent years have seen a number of new specimens of Long-tailed Birds, suggesting this was a distinct group of animals that...

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A fossil Pterosaur from the Early Cretaceous of Liaoning Province, China.

Among the many remarkable fossils of the Jehol Biota Lagerstätte of northeast China a number of well preserved Pterosaurs have been discovered. One of these, Feolongus youngi, from the Yixian Formation of western Liaoning Province, is thought to have been the first known Chinese Pterosaur to reach sizes in excess of a two meter wingspan; although this is somewhat speculative, based upon reconstruction of the animal from a partial skull.

In a paper published in the journal Acta Geologica Sinica in February 2014, Wang Xuri of the Institute of Geology at the Chinese Academy of Geological Sciences, Shen Caizhi and Gao Chunling of the Dalian Natural History Museum and Jin Kemo of the Chinese Academy of Geological Sciences describe a new partial Pterosaur skull from the Early Cretaceous Jiufotang Formation of western Liaoning Province. 

The new specimen lacks either of the two key characteristics of Feolongus youngi; a sagittal cranial crest and an elongate, overhanging upper jaw; the crest is not preserved due to the absence of the sagittal region of the skull. Wang et al. dispute the value of either of these traits for diagnostic purposes. They reason that crests are often sexual display features, which may only be found in one sex of any given species. Wang et al. also question the validity of the overhanging jaw seen in the original specimen of Feolongus youngi, suggesting that it may instead be a taphonomic artifact (result of post-mortem events, rather than of the biology of the living animal) caused by crushing of the skeleton during preservation. 

Skull of Feolongus sp. from the Early Cretaceous Jiufotang Formation of western Liaoning Province. Wang et al. (2014).

Wang et al. do not go as far as placing the new specimen in the same species as the original, since both are somewhat fragmentary and may share or lack common features on the rest of the skeleton, but do place it within the same genus as Feolongus sp.

See also...

 A giant Pterosaur from the Middle Cretaceous of Brazil.

 A small Pterosaur from the Early Cretaceous of the Isle of Wight.

 A new species of Azhdarchid Pterosaur from the Late Cretaceous of Transylvania.

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