Jiufotang Research Articles

A possible azhdarchid pterosaur from the Lower Cretaceous Qingshan Group of Laiyang, Shandong, China

ABSTRACT A new pterodactyloid pterosaur is identified from the Early Cretaceous Doushan Formaiton of Laiyang, Shandong Province, China, based on a fragmentary humerus. The humerus exhibits several diagnostic characters: deltopectoral crest is elongate and un-warped, its base is slightly displaced relative to the humeral shaft axis, and the crest is swollen terminally and ventrally displaced; humeral shaft is straight and thin-walled with a ‘D’-shaped cross-section. Based on these features, the specimen is referable to the superfamily Azhdarchoidea as Azhdarchidae indet. As the oldest known azhdarchid fossil, the specimen represents a significant stratigraphic range extension for the family. Other non-azhdarchid azhdarchoids such as tapejarids and chaoyangopterids are common in the Jiufotang Formation of western Liaoning, which possibly is equivalent to the Doushan Formation of Laiyang with an age of about 120 Ma. Consequently, the possible coexistence of these azhdarchoids lineages documents that the azhdarchids split from the main azhdarchoid clade occurred no later than the Early Cretaceous.

A new eucryptodiran turtle from the Early Cretaceous Jiufotang Formation of western Liaoning, China

A new eucryptodiran turtle from the Jiufotang Formation of Lamadong, Jianchang County, represents the third turtle taxon, Liaochelys jianchangensis gen. et sp. nov., from the Jehol Biota of western Liaoning Province, China. This taxon is diagnosed by a character combination including a midline contact of the prefrontals, vertebrals wider than long, third costals strongly expanded distally, and a medial contact of the eighth costals. A preliminary cladistic analysis places Liaochelys jianchangensis along the phylogenetic stem of Cryptodira in a position more derived than the taxa, Manchurochelys manchoukuoensis and Ordosemys liaoxiensis, known from the underlying Yixian Formation. This discovery opens a new window into the osteology and evolution of primitive eucryptodiran turtles.

Evolution of insect diversity in the Jehol Biota

Insects of the Jehol Biota, also known as the Jehol Entomofauna, can be divided into three phases, approximately corresponding to the early, middle, and late Jehol Biota. The early phase of the entomofauna is found in the Dabeigou Formation and its coeval horizons (ca. 135–130 Ma). The middle phase is recorded from the lower-middle Yixian Formation (underlying the Jingangshan Bed) and its coeval strata (ca. 130–122.5 Ma). The late phase is found in the lower Jiufotang Formation, the upper Yixian Formation (the Jingangshan and Huanghuashan beds) and their coeval horizons (ca. 122.5–120 Ma). In major distribution areas of the Jehol Biota, the entomofauna changed greatly in species diversity with about 150 species in about 40 families and 11 orders in the early phase, a great increase up to about 500 species in about 100 families and 16 orders in the middle phase, and a decline to about 300 species in about 80 families and 14 orders in the late phase. The entomofauna can also be divided into four insect communities based on habitats or five insect groups based on feeding habits. Each community or group varied in species diversity in a similar trend to the whole entomofauna. However, it kept a comparatively stable position in the ecosystem. Of the four communities, the highest species diversity occurred in the forest community, followed by the aquatic, the soil, and the alpine communities. Of the five groups, the highest species diversity appeared in the phytophagous group, followed by the carnivorous, the parasitic, the saprophagous, and the heterophagous groups.

Two Early Cretaceous fishes discovered from the most northern area of China: implications for the palaeobiogeography of the Jehol Biota

AbstractFrom a newly discovered Early Cretaceous fossil site at the Sanlianhe Coal Mine in Tahe County, Heilongjiang Province, the most northern area in China, two freshwater fossil fish had been recovered. This paper reports their classifications and implications regarding the palaeobiogeography of the Jehol Biota. The fish assemblage consists of Yanosteus sp. (Acipenseriforms) and Sinamia sp. (Amiiformes). Both are important members of the well known Jehol Biota, and their occurrence supports the correlation of the Yiliekede Formation at Sanlianhe Coal Mine site with the Jiufotang Formation of West Liaoning. The remains of the Yanosteus sp. from this locality is the first known record of the genus other than in the Yan‐Liao area of China, and the specimens of Sinamia sp. is quite similar to what may be a new species of Sinamia from West Liaoning. The new fossil site represents the most northern site that is undoubtedly part of the extent of the Jehol Biota as currently understood. The northern Great Xing'an Range area is an important region that may link correlations between the Early Cretaceous continental biotas of China, Mongolia and Russia. Copyright © 2010 John Wiley & Sons, Ltd.

A New Species of Huaxiapterus (Pterosauria: Pterodactyloidea) from the Lower Cretaceous of Western Liaoning, China with Comments on the Systematics of Tapejarid Pterosaurs

A new species of tapejarid pterosaur, Huaxiapterus corollatus sp. nov. is erected on the basis of a nearly complete skull and postcranial skeleton from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China. Huaxiapterus corollatus sp. nov. is characterized by a hatchet-shaped rectangular process on the premaxilla, whose short axis is perpendicular to the anterior margin of the premaxillae. Except for this process, other characters of the skull such as the breadth of the snout between the anterior margin of the nasoantorbital fenestra and the anterior margin of the premaxilla are similar to that of Huaxiapterus jii. Huaxiapterus and a second Chinese tapejarid, Sinopterus, share several unique cranial characters in common with Tapejara and these three genera appear to be more closely related to each other than to other azhdarchoids. The Chinese tapejarids (Sinopterus and Huaxiapterus) have relatively elongate skulls and weakly developed cranial crests and seem to be less derived than Tapejara, with its shorter, deeper skull and large cranial crest. Tupuxuarids (Tupuxuara and Thalassodromeus) have often been associated with tapejarids in the family Tapejaridae, but this relationship is controversial because some phylogenetic analyses have supported the pairing of tupuxuarids with Azhdarchidae. We propose that Tapejaridae be restricted to Tapejara, Sinopterus and Huaxiapterus.

New material of Chaoyangopterus (Pterosauria: Pterodactyloidea) from the Early Cretaceous Jiufotang Formation of western Liaoning, China

A new edentulous pterosaur from the Yuanjiawa beds of the Early Cretaceous Jiufotang Formation in Yuanjiawa, Chaoyang, western Liaoning, China, is described. The fossil, an incomplete and scattered skeleton, including partial skull and lower jaws, is identified as Chaoyangopterus zhangi, based on similar proportions of the limb bones. The specimen shows that Chaoyangopterus possessed moderately elongate mid-cervical vertebrae with low, blade-like neural spines and lacked lateral pneumatic foramina. This discovery not only further supports a distinct Chaoyangopteridae within the Azhdarchoidea, but also provides a new scope for reviewing the evolution of the family Azhdarchidae.

A New Enantiornithine Bird From the Early Cretaceous of Western Liaoning, China

Abstract. We describe a new enantiornithine bird, Huoshanornis huji gen. et sp. nov., from the Early Cretaceous Jiufotang Formation in Chaoyang, western Liaoning Province, China. This new bird is distinguished from other known enantiornithines in possessing a considerably reduced alular digit, a broad intermetacarpal space, a relatively long phalanx of the minor digit of the manus, and a remarkable triangular expansion at the distal end of the lateral trabecula of the sternum. The morphology of the manus may also suggest that at low flight speeds the new bird's maneuverability was exceptional.

A new Lower Cretaceous bird from China and tooth reduction in early avian evolution

A new avian genus and species, Zhongjianornis yangi gen. et sp. nov., is reported from the Lower Cretaceous lacustrine deposits of the Jiufotang Formation in Liaoning, northeast China. The new taxon is characterized by possessing the following combination of features: upper and lower jaws toothless, snout pointed, humerus with large and robust deltopectoral crest, second phalanx of the major manual digit longer than the first phalanx, unguals of the alular and major digits of similar length and significantly shorter than the corresponding penultimate phalanges, tibiotarsus slender and more than twice the length of the tarsometatarsus, and metatarsal IV longer than the other metatarsals. Phylogenetic analysis indicates that Zhongjianornis is phylogenetically basal to Confuciusornis and the dominant Mesozoic avian groups, Enantiornithes and Ornithurae, and therefore provides significant new information regarding the diversification of birds in the Early Cretaceous. It also represents the most basal bird that completely lacks teeth, suggesting that tooth loss was more common than expected in early avian evolution and that the avian beak appeared independently in several avian lineages, most probably as a response to selective pressure for weight reduction. Finally, the presence of a significantly enlarged humeral deltopectoral crest suggests that Zhongjianornis shares with other basal birds such as Jeholornis, Sapeornis and Confuciusornis a distinctive mode of adaptation for flight contrasting with that seen in more advanced birds, which instead possess an elongated sternum and a prominent keel.

High-precision 40Ar/ 39Ar age for the Jehol Biota

Abundant fossils of the terrestrial Jehol Biota, including plants, insects, dinosaurs, birds, mammals and freshwater invertebrates, were discovered from the Yixian Formation and the overlying Jiufotang Formation in Inner Mongolia, Hebei Province and Liaoning Province, northeastern China. Because of the exceptional preservation of fossils, the Jehol Biota is one of the most important Mesozoic lagerstätten and is referred to as a “Mesozoic Pompeii”. The Jehol Biota has provided a rare opportunity to address questions about the origin of birds, the evolution of feathers and flight, the early diversification of angiosperms and the timing of placental mammal radiation. Six tuff samples and two basalt samples collected from the Tuchengzi, the Yixian and the Jiufotang formations near the classic outcrops in western Liaoning, NE China yielded high-precision 40Ar/ 39Ar ages. We obtain an age of 129.7 ± 0.5 Ma for a basaltic lava from the bottom of the Yixian Formation and an age of 122.1 ± 0.3 Ma for a tuff from the lowermost part of the overlying Jiufotang Formation. Our age results provide an age calibration of the whole Yixian Formation and show that the whole formation was deposited entirely within Early Cretaceous time over an interval of ~ 7 Ma.

Anatomy of the Early Cretaceous bird Rapaxavis pani, a new species from Liaoning Province, China

ABSTRACT The lacustrine deposits of the Jiufotang Formation, Liaoning Province, China have yielded a diverse avifauna representing a wide spectrum of basal lineages. Here we add to this diversity by describing the longirostrine enantiornithean taxon Rapaxavis pani gen. et sp. nov. The specimen possesses the following autapomorphies: (1) caudoateral processes of the sternum with two prominent branches and a smaller third branch, (2) paired triangular thoracic elements of unknown homology, and (3) the combination of six sacral vertebrae and six free caudal vertebrae. Otherwise, this genus is closely allied with the Yixian Formation species Longirostravis hani, sharing elongate, curving rostrum with teeth restricted to the premaxilla and rostral-most dentary, and a derived manus lacking unguals. The holotype of Rapaxavis is exquisitely preserved, with such details as distal tarsals, keratinous sheaths of the pedal unguals and some three-dimensional features of the bones intact. The holotype appears to lack a fused tibiotarsus and a fused carpometa-carpus. These features may indicate that the specimen is not yet fully grown, though the life stages of members of the Enantiornithes will not be clear until a complete ontogenetic series can be constructed. A comparison of the proportions of the pedal phalanges of Rapaxavis to modern birds shows Rapaxavis to be highly adapted to a grasping, arboreal lifestyle. The combination of strongly arboreal pedal adaptations and the probing adaptations in the rostrum is here confirmed in a member of the Enantiornithes for the first time in the literature, adding to their already impressive known functional diversity.

A primitive istiodactylid pterosaur (Pterodactyloidea) from the Jiufotang Formation (Early Cretaceous), northeast China

A primitive istiodactylid pterosaur (Pterodactyloidea) from the Jiufotang Formation (Early Cretaceous), northeast China

A New Species of Cathayornis from the Lower Cretaceous of Inner Mongolia, China and Its Stratigraphic Significance

Abstract: An incomplete postcranial avian skeleton is described from the Lower Cretaceous Jingchuan Formation of Otog Banner of western Inner Mongolia and referred to a new species of Cathayornis, C. chabuensis sp. nov. This is the first report of a Cathayornis from outside Liaoning Province. The new discovery indicates that Cathayornis coexisted with Otogornis genghisi, and a more detailed comparison between these two enantiornithine genera shows that Otogornis represents a more primitive genus than Cathayornis. Our analyses further indicate that Cathayornis is an arboreal bird. The discovery of a Cathayornis from this region also confirms that the avian fossil‐bearing Jingchuan Formation is comparable to the Jiufotang Formation of the upper Jehol Group in western Liaoning, and should be referred to the middle‐late Early Cretaceous.

A NEW AZHDARCHOID PTEROSAUR FROM THE CRATO FORMATION (LOWER CRETACEOUS, APTIAN?) OF BRAZIL

Abstract: A partial pterosaur skull from the Nova Olinda Member of the Crato Formation (Lower Cretaceous, Aptian?) represents a new edentulous pterodactyloid, Lacusovagus magnificens gen. et sp. nov. The absence of teeth and a large nasoantorbital fenestra suggest assignment to Azhdarchoidea, and the combination of a particularly short, crestless and shallow rostrum and laterally flared jaw margins distinguish it from other azhdarchoid taxa. The position of the new form within Azhdarchoidea is problematic: Lacusovagus is distinguished from Tapejaridae in its straight, as opposed to ventrally displaced, jaw tip and absence of a premaxillary crest; from thalassodromids by the absence of a premaxillary crest; and from Azhdarchidae by the short length of the rostrum and shallow posterodorsal extension of the premaxilla. Lacusovagus shares a shallow, crestless rostrum and a slender posterodorsal premaxillary extension with Jiufotang Formation azhdarchoids such as Chaoyangopterus and Jidapterus. The position of these genera within Azhdarchoidea is controversial, but the suite of plesiomorphic and derived azhdarchoid characters in each suggests a placement between Tapejaridae and Neoazhdarchia. Further research is required, however, to determine the relationships of these genera both to each other and to other azhdarchoids. The new taxon elevates the faunal similarity found between the roughly contemporaneous Jiufotang and Crato formations and continues the pattern of Crato Formation azhdarchoids being much larger than those from the Jehol Group. It also has jaws at least 67 and 55 per cent longer, respectively, than those of the largest azhdarchoids and ornithocheirids from the Crato pterosaur assemblage, making Lacusovagus the largest pterosaur known from this unit.

A primitive istiodactylid pterosaur (Pterodactyloidea) from the Jiufotang Formation (Early Cretaceous), northeast China

A new pterosaur, Hongshanopterus lacustris gen. et sp. nov., from the Early Cretaceous Jiufotang Formation, western Liaoning, China is described. The specimen (IVPP V14582) consists of a skull preserved in palatal view and some isolated cervical vertebrae. Based on the labiolingually compressed teeth with a triangular crown Hongshanopterus lacustris is referred to the Istiodactylidae. It presents several plesiomorphic features such as the teeth not confined to the anterior third of the skull but extended more posteriorly, and is thus considered the most primitive member of this group. This new species also differs from other istiodactylids by having more teeth, some showing the crown distinctively directed posteriorly. Three other members of the Istiodactylidae are currently represented in the Jiufotang deposits: Nurhachius ignaciobritoi, Istiodactylus sinensis and Longchengpterus zhaoi. To those we add Liaoxipterus brachyognathus, previously classified in the Ctenochasmatidae but that also has triangular labiolingually compressed teeth, and is a potential senior synonym of Lonchengpterus zhaoi. The palatal anatomy of Hongshanopterus lacustris also agrees with previous hypothesis that considers Istiodactylidae more closely related to the Anhangueridae than to Pteranodon (or Pteranodontidae).

A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution

Toothless pterosaurs played a key role in broadening the taxonomic, morphological and ecological diversity of Cretaceous pterosaurs. Here we report a complete, articulated skeleton of a 1.4-m-wingspan pterosaur from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China which is identified as a new genus and species, Shenzhoupterus chaoyangensis gen. et sp. nov. The new taxon is edentulous, with a relatively large skull and a remarkably large, tall nasoantorbital fenestra that extends well above the main part of the braincase. Phylogenetic analysis shows that Shenzhoupterus gen. nov. belongs in a distinct clade of azhdarchoid pterosaurs, formally recognised here as a new family, Chaoyangopteridae, that also includes Chaoyangopterus, Jidapterus and Eoazhdarcho from the Jiufotang Formation and Eopteranodon from the Yixian Formation. These new data clarify recent confusion surrounding the systematics of these Lower Cretaceous taxa and provide new insights into the evolutionary history of pterosaurs.

Discovery of a rare arboreal forest-dwelling flying reptile (Pterosauria, Pterodactyloidea) from China

A previously undescribed toothless flying reptile from northeastern China, Nemicolopterus crypticus gen. et sp. nov., was discovered in the lacustrine sediments of the Early Cretaceous Jiufotang Formation, western Liaoning, China. The specimen consists of an almost complete articulated skeleton (IVPP V14377) and, despite representing an immature individual, based on the ossification of the skeleton, it is not a hatchling or newborn, making it one of the smallest pterosaurs known so far (wing span approximately 250 mm). It can be distinguished from all other pterosaurs by the presence of a short medial nasal process, an inverted "knife-shaped" deltopectoral crest of the humerus, and the presence of a well developed posterior process on the femur above the articulation with the tibia. It further shows the penultimate phalanges of the foot curved in a degree not reported in any pterosaur before, strongly indicating that it had an arboreal lifestyle, more than any other pterodactyloid pterosaur known so far. It is the sister-group of the Ornithocheiroidea and indicates that derived pterosaurs, including some gigantic forms of the Late Cretaceous with wingspans of >6 m, are closely related to small arboreal toothless creatures that likely were living in the canopies of the ancient forests feeding on insects.

A New Genus and Species of Sapeornithidae from Lower Cretaceous in Western Liaoning, China

Abstract: Sapeornithidae is a basal pygostylian family of Early Cretaceous primitive birds, in which only one genus and species, Sapeornis chaoyangensis, was reported before. This paper deals with a new genus and species of this family, Didactylornis jii gen. et sp. nov., which was unearthed from the Early Cretaceous Jiufotang Formation in western Liaoning. According to our phylogenetic analyses, both Didactylornis gen. nov. and Sapeornis form a sister group, which is basal to the clade formed by Confuciusornis and all the more derived birds, and more closely related to the short‐tailed pygostylian birds than to the long‐tailed avialian birds. The early history of pygostylian birds is poorly documented except for the studies of Confuciusornis and Sapeornis. The discovery of Didactylornis jii gen. et sp. nov. adds the new material for the study on the early evolution of birds.

The remarkable fossils from the Early Cretaceous Jehol Biota of China and how they have changed our knowledge of Mesozoic life: Presidential Address, delivered 2nd May 2008

Palaeontologists and others have been repeatedly amazed by reports of spectacularly well-preserved fossils from China, and one of the key sources has been the Jehol Biota of Liaoning, Hebei and Inner Mongolia in NE China. The Jehol Biota consists of three main horizons, the Dabeigou, Yixian and Jiufotang formations, spanning the late Hauterivian to early Aptian (131-120 Ma) of the Early Cretaceous and, collectively, these have produced thousands of essentially complete specimens of plants, insects, aquatic invertebrates, fishes, frogs, salamanders, turtles, lizards, choristoderes, pterosaurs, dinosaurs, birds and mammals. Most of the specimens show some aspect of exceptional preservation, ranging from clear impressions of the body outlines to traces of soft tissues (liver, teleost air sac, eye spots) and external body coverings (scales, feathers, hair). The claim was made that these discoveries have revolutionized our understanding of evolution through this critical part of the Cretaceous Terrestrial Revolution. Key insights have come from the numerous specimens of dinosaurs with feathers, but numerical study shows that only the finds of birds and mammals have substantially changed our views about global diversity and patterns of evolution through the Early Cretaceous.

Precious Fossil‐Bearing Beds of the Lower Cretaceous Jiufotang Formation in Western Liaoning Province, China

Abstract: Based on the subdivision into three members of the Lower Cretaceous Jiufotang Formation in western Liaoning, this paper deals mainly with the division and correlation of precious fossil bird‐and reptile‐bearing beds of the formation in the Dachengzi, Chaoyang, Dapingfang‐Meileyingzi and Fuxin‐Yixian basins. Among them, the precious fossil‐bearing beds in the Dachengzi Basin may be recognized as the Xidagou Bed of the second member and the Yangcaogoudonggou Bed of the third member; those in the Chaoyang Basin may be confirmed as the Shangheshou Bed of the second member and the Dongpochi Bed of the third member; those in the Dapingfang‐Meileyingzi Basin are as the Lamagou Bed of the second member, the Huanghuagou Bed of the lower third member and the Yuanjiawa Bed of the upper third member; and those in the Fuxin‐Yixian Basin are listed as the Tuanshanzi Bed of the second member and the Pijiagou Bed of the third member. Since these basins are distinctly separated and the bird and reptile fossils are mostly new genera and species, we have to use the associated fossil ostracod assemblages as index to correlate the Xidagou Bed with the Shangheshou Bed and the Lamagou Bed, and to correlate the Yuanjiawa Bed with the Yangcaogoudonggou Bed and the Pijiagou Bed. Primarily, we established the sequence of the precious fossil‐bearing beds of the Jiufotang Formation in western Liaoning. They are represented by, in ascending order, the Xidagou Bed of the second member, the Huanghuagou Bed of the lower third member, and the Yuanjiawa Bed of the upper third member. Obviously, this work has significance for the study on the time‐space distribution and radiation of birds and dinosaurs during the period of the middle Early Cretaceous.

Yanjiestheria, Yanshania and the development of the Eosestheria conchostracan fauna of the Jehol Biota in China

Re-examination of specimens of the type species of Yanjiestheria ( Y. bellula), from the Albian Dalazi Formation in eastern Jilin, and Yanshania ( Y. dabeigouensis), from the Berriasian Dadianzi Formation in northern Hebei, under a scanning electron microscope has confirmed that Yanshania is a junior synonym of Yanjiestheria. This means that the earliest occurrence of Yanjiestheria precedes that of Eosestheria in northern Hebei, indicating that it cannot have descended from the latter, as has been suggested previously; rather the two genera must have evolved in parallel. An analysis of the changes in diversity of components of the Eosestheria fauna of the Jehol Biota indicates that the increase in the number of genera and species, which began during the deposition of the Jianshangou Beds of the Yixian Formation, may have been connected with the dispersal of conchostracan taxa to north-east China, Inner Mongolia, west and south Mongolia and elsewhere from what appears to have been their main centre of origin in northern Hebei. The Eosestheria fauna continued to flourish until deposition of the Jiufotang Formation came to an end.