Dongbeititan dongi,the First Sauropod Dinosaur from the Lower Cretaceous Jehol Group of Western Liaoning Province,China

We herein describe a partial postcranial skeleton of a sauropod dinosaur recovered from the Lower Cretaceous Jehol Group in the Beipiao area of western Liaoning Province, northeastern China. A suite of features it possesses, including the camellate internal structure of its presacral elements, the existence of pneumatocoels on the proximal ends of the dorsal ribs, and especially the medially deflected proximal portion of the femur, definitively establish the titanosauriform affinities of the specimen. It differs from other titanosauriforms in having a craniocaudally elongate coracoid with a squared cranioventral extreme and a long, smooth, and slightly convex acetabular edge of the pubis. It represents a new taxon, Dongbeititan dongi gen. et sp. nov. Comparative studies suggest that Dongbeititan is a basal titanosauriform, more derived than Euhelopus, Fusuisaurus, and Huanghetitan, but less derived than Gobititan and Jiutaisaurus. Dongbeititan represents the first sauropod dinosaur reported from the Lower Cretaceous Jehol Group of western Liaoning Province.

New Fossil Beetles of the Family Elateridae from the Jehol Biota of China(Coleoptera:Polyphaga)

Two new species of elaterids assigned to two new genera with intriguing fossa on prosternum are described and illustrated： Bilineariselaterfoveatus gen. et sp. nov. and Curtelater wui gen. et sp. nov. from the Upper Jurassic-Lower Cretaceous Yixian Formation of western Liaoning, China. The origin of the clicking mechanism in these beetles and the systematic position of the two genera are briefly discussed.

Solenites (Czekanowskiales) from the Late Mesozoic Jehol Biota of Southeastern Jilin,China and its Paleoclimatic Implications

Situated at the easternmost area of the Late Mesozoic Jehol Biota, China, abundant fossils, including invertebrates, vertebrates and plants, were collected from the Early Cretaceous Yingzuilazi Formation of the Baishan Basin, southeastern Jilin. The faunal remains from this formation distinctly belong to the Early Cretaceous Lycoptera-Ephemeropsis-Eosestheria assemblage of the Jehol Biota. Based on the gross leaf morphology and epidermal structures, two new species and one indeterminate species of genus Solenites （Czekanowskiales）, S. baishanensis sp. nov., S. gracilis sp. nov. and S. sp. are described in this paper. This is the first fossil plant of Czekanowskiales reported from this new fossil locality of the easternmost area of the Late Mesozoic Jehol Biota, China. The new discovery contributes to improve our knowledge for understanding of leaf morphology, epidermal characters and diversity of this genus during the Early Cretaceous time, and extends geologic and geographic distribution of Solenites in northern China and Eurasia. Along with consideration of associated plant and faunal assemblages and sedimentology, we suggest that the regional climate was warm and moderately humid with seasonal temperature and precipitation variations in warm-temperate zone during the Early Cretaceous.

New Fossil Beetles of the Family Ommatidae (Coleoptera: Archostemata) from the Jehol Biota of China

A new genus with one new species and five new species of genus Amblomma of fossil ommatids are described and illustrated： Euryomma tylodes gen. et sp. nov., Amblomma cyclodonta sp. nov., Amblomma miniscula sp. nov., Amblomma porrecta sp. nov., Amblomma eumeura sp. nov., and Amblomma protensa sp. nov. All of them were collected from the Upper Jurassic or Lower Cretaceous Yixian Formation of western Liaoning, China. A key to the species of Amblomma is given. The wide epipleural space shows that Euryomma may be a primitive genus in Ommatidae. Many different species of Amblomma occurred within the same sedimentary horizon in this area could be environmental changes caused by frequent volcanic activities during the deposition of the Yixian Formation.

Two New“Notostracans”,Chenops gen.nov.and Jeholops gen.nov. (Crustacea:Branchiopoda:?Notostraca) from the Yixian Formation,Northeastern China

The Early Cretaceous Jehol biota of northeastern China contains a diverse group of notostracans, including two genera, Chenops and Jeholops, described here. Chenops is characterized by a combination of an ovate carapace, narrow anal plate, equant distal endites and endopod on the anterior thoracic limbs. In addition to the new species, Chenops yixianensis, the genus also provisionally includes Prolepidurus oblongus Oleynikov, 1968. Jeholops, however, is monotypic, represented by the new species Jeholops hongi. It is characterized by a combination of kazacharthran and notostracan features unique to this taxon. Both new genera are provisionally placed in the taxon Notostraca. More detailed work exploring the morphology of exceptionally-preserved branchiopod crustaceans is needed. The difficulties in placing fossil notostracans into a phylogenetie framework are discussed.

First Zircon U-Pb Ages of the Pigeon Hill Fossil Locality of the Jehol Biota in the Greater Khingan Mountains, Inner Mongolia

Objective The Pigeon Hill fossil locality yielded a diversity of fossils of the Jehol Biota.It sheds new light on the evolution of the Jehol Biota in more distant paleogeographic locations.Although several taxa of extinct vertebrates were described from the Pigeon Hill.

A Mesozoic Pompeii: History of the Jehol Biota's Rise and Fall

The Jehol fauna was initially represented by a bony fish, concostracan and an insect, as a Lycoptera davidi-Eosestheria-Ephemeropsis trisetalis association,but since the researches of recent decades, the Jehol Biota is now completely different from the past low-diversity, and encompasses a native terrestrial biota that includes many well-preserved vertebrates, invertebrates and plants. There are more than 20 important biological categories, thousands of taphonomically unusual fossils, especially noted for the wide variety of biological tissues. The Jehol Biota has caused a sensation in the world with its wide distribution, large quantity, great variety, fine preservation and detailed information, which records the rise and fall of the numerous taxa, and provides significant evidence for three origins： of birds, eutherian mammals, and angiosperms. The Jehol Biota is a highlight of basic scientific research in China, and we honor it as a world-class fossil treasury and ＂a Mesozoic Pompeii＂.

A reassessment of Iteravis huchzermeyeri and Gansus zheni from the Jehol Biota in western Liaoning, China

The authors reassessed the taxonomic distinction of Iteravis huchzermeyeri and Gansus zheni,which are two species of Ornithuromorpha based on specimens from the same locality in western Liaoning and derive from the Jehol Biota.The detailed comparisons of the holotype and referred specimens of both species,reveal no anatomical features that distinguish these taxa as separate species.Some minor differences are considered to relate to ontogenetic or interspecific differences.The stratigraphic occurrence for both specimens is the Lower Cretaceous Jiufotang Formation.Accordingly,the authors conclude that Iteravis huchzermeyeri has priority,by 15 days,for this taxon and that Gansus zheni is a junior synonym.The diagnosis of Iteravis huchzermeyeri is revised based on further study on all specimens referred to this species.Its generic distinction from Gansus is maintained thereby removing a potential genus-level correlation linking Xiagou Formation in Gansu Province with the Jiufotang Formation in Liaoning Province.

Palaeoenvironments and Taphonomy of Bird Fossils(Early Cretaceous) from Jehol Biota in Western Liaoning,China

Jehol Biota in western Liaoning and northern Hebei has been a hot topic of global concern,a large number of exquisite fossils were found in Yixian group Sihetun,such as Sinosauropteryx,Protarchaeopteryx, Caudipteryx and Confuciusornis.Scientists consider the discovering of Sinosauropteryx discovered so far as the earliest ancestor of birds.According to the dates of root layer,we can see warm and humid,lakes

Origin, Evolution and Mechanism of the Jehol Fauna

This paper deals with the geographic distribution and geological setting of the Jehol (northeastHebei-southwest Liaoning-southeast Inner Mongolia) fauna, and discusses the origination and the evolution ofits major biological groups. It is demonstrated that the Yan-Liao (northern Hebei-western Liaoning) area is theprovenance for the fauna. Why the fauna originated and developed in the area was intimately related to suchfactors as the palaeoclimate, palaeogeography, crustal movement, volcanism and frequent reversals of magnet-ic polarity at that time, in addition to the internal factors of the organisms themselves.

The First Discovery of the Easternmost Jehol Biota from Southeastern Jilin, China

Objective The Jehol Biota, a world-famous Early Cretaceous fossil Lagersttate characterized by the traditional Eosestheria-Ephemeropsis-Lycoptera （EEL） assemblage, has a wide distribution over most parts of northem China, the coastal area of southeastem China, southeastem Mongolia, Transbaikalian area of Russia, Korea and Japan （Shao et al., 2017）. The Baishan Basin, situated in southeastern Jilin is one of the easternmost Jehol Biota localities in China. Until now, the fossils here belonging to Jehol Biota have not yet been reported except for few fossils listed in geological survey reports. The fossil collections here are noteworthy in that they are the first fossil record documented from the Early Cretaceous Yingzuilazi Formation of the Baishan Basin, southeastern Jilin and the easternmost locality of Jehol Biota, China. This finding is important to explore the distribution, evolution and biodiversity of the Jehol Biota and even the Late Mesozoic terrestrial ecosystem, as well as for the division and correlation of the Late Mesozoic terrestrial strata.

The First Vertebrate Assemblage Dominated by Fishes and Turtles of the Jehol Biota in Jilin Province, NE China

Objective The Early Cretaceous sediments are well-exposed in southern Jilin Province,and yield abundant invertebrate and plant fossils,including the typical EosestheriaEphemeropsis trisetalis-Lycoptera（E-E-L）assemblage of the Jehol Biota（Shao Tiequan et al.,2017）.However,vertebrate fossils,especially tetrapods,are extremely rare and there is no formal documents on these fossils.Recently,a new fossil site dominated by fishes and turtles has been discovered in the middle part of the

Taphonomy and Paleoecology of Lycoptera: A Case Study from the Lower Jehol Group in Western Liaoning, Northeastern China

Taphonomy and paleoecology(biological behavior)of the Early Cretaceous fish fossils are poorly described.This study reports for the first time a detailed taphonomical and paleoecological study on Lycoptera in the Mesozoic strata of western Liaoning Province,NE China.The XRD analysis shows that gismondine is the dominant clay minerals that could have contributed to the preservation of Lycoptera fossils and microbial mat fragments in the fossil-bearing horizon.Gismondine may have formed under volcanism-related hydrothermal regime that was transformed from crystal and lithic fragments.Theμ-XRF imaging analysis shows a dominant chemical composition of Al,Si,P,S,Rh,K,Ca,Ti,C,Cr,Mn,Fe,Ni,among which P,Ca,C and S are enriched in the fish skeleton in comparison to the matrix.This suggests a dominant apatite composition for the fish skeleton.Hydrothermal influence did not smear off these organic signals probably because of protection of gismondine.The coexistance of C and S with Ni is assumed to represent recovered primary productivity following volcanic explosions and toxic gas emissions.The head of juvenile fish stays close to the body of adult fish.Pending further discoveries,such phenomenon is interpreted to suggest that adult fish actively protected juvenile fish in the presence of environmental pressures such as anoxia and deterioration of water quality induced by volcanism.Ocean acidification and hypoxia in association with volcanism created a harmful environment causing mass extinction of fish.The adult Lycoptera protected their juveniles by its body at the moment before death.Such biological behavior will be increasingly reported given the wide occurrence of Lycoptera in Mesozoic strata.

Sinobaatar gen. nov.: First multituberculate from the Jehol Biota of Liaoning,Northeast China

A multituberculate skeleton from the Lower Cretaceous Yixian Formation at Dawangzhangzi, Lingyuan City, Liaoning Province, Northeast China, provides new morphological information for early multituberculates. The specimen is the holotype of Sinobaatar lingyuanensis gen. et sp. nov. It has a narrow skull that lacks the superorbital crest or postorbital process. The dental formula is 3·?·5·2/1·0·3·2. The dental morphology, especially that of cheek teeth, of S. lingyuanensis is similar to that of Eobaatar, which places it in the family Eobaataridae. The postcranial skeleton of Sinobaatar is similar to that of other multituberculates. As in Holotheria, Metatarsal V of Sinobaatar articulates only with the cuboid and has no contact with the calcaneus, which probably represents the primitive condition of multituberculates. Nine carpals of Sinobaatar resemble those of Zhang-heotherium, except the centrale being larger than the trape-zoid. The dental features of Sinobaatar show again that eo-baatarids are

Vertebrate diversity of the Jehol Biota as compared with other lagersttten

In the last twenty years,the extraordinary discoveries of vertebrate fossils from the Jehol Biota not only have important impli-cations for studying the evolution of major Mesozoic vertebrate groups,their paleobiostratigraphy and paleoenvironmentology,but also provide critical evidence for understanding the biodiversity changes of the Early Cretaceous ecosystem.Currently,the Jehol Biota in a narrow sense(i.e.,distribution limited to western Liaoning,northern Hebei,and southeastern Inner Mongolia) comprises a vertebrate assemblage of at least 121 genera and 142 species.Among them are 13 genera and 15 species of mammals,33 genera and 39 species of birds,30 genera and 35 species of dinosaurs,17 genera and species of pterosaurs,5 genera and species of squamates,5 genera and 7 species of choristoderes,2 genera and species of turtles,8 genera and species of am-phibians,7 genera and 13 species of fishes as well as 1 genus and species of agnathan.All these known 121 genera are extinct forms,and only a small percentage of them(e.g.,agnathans,some fishes and amphibians) can be referred to extant families.The Jehol vertebrate diversity already exceeds that of the contemporaneous lagersttten such as Santana Fauna from Brazil and the Las Hoyas Fauna from Spain,and is nearly as great as that of the Jurassic Solnhofen Fauna and the Eocene Messel Fauna from Germany.Therefore,The Jehol Biota undoubtedly represents a world class lagerst?tte in terms of both fossil preservation and vertebrate diversity.The success of the Jehol vertebrate diversity had a complex biological,geological,and paleoenviron-mental background.Analysis of the habitat and diet of various vertebrate groups also indicates that the habitat and dietary dif-ferentiation had played a key role in the success of the taxonomic diversity of vertebrates of various ranks.Furthermore,the interactions among vertebrates,plants,and invertebrates as well as the competitions among various vertebrate groups and some key morphological innovations also contributed to the success of the Jehol vertebrate diversity.

Morphological variation in fossil crayfish of the Jehol biota,Liaoning Province,China and its texonomic discrimination

Twelve morphological characteristics in 61 fossil crayfish specimens, which came from the Upper Jurassic Yixian Formation, are discussed respectively in the present paper. A study of these new and better preserved materials allows us to add to and revise the original description for Family Cricoidoscelosidae. In our collection, no modifications of the second pleopod of the males have yet been noted. This would be a crucial factor for the diagnosis of the family. Based on the presence of annulus ventralis in both Cricoidoscelosus and Palaeocambarus, they would appear to be very closely allied to those characteristics of the Family Cambaridae. In regard to the family Protastacidae, we seriously doubt it is actually crayfish, in light of the lack of any apomorphies identifiable within the Astacida, and their marine habitat.

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.

Study on the Jehol Biota:Recent advances and future prospects

The Jehol Biota is an Early Cretaceous terrestrial fossil assemblage of paramount significance,and its core distribution areas are western Liaoning,northern Hebei,and southeastern Inner Mongolia.Despite with a research history of more than 150 years,it started yielding important fossils until early 1990s,which include feathered dinosaurs,early birds,early mammals,flower-visiting insects,and early angiosperms.These discoveries have implications for understanding the origins and early evolution of several major organismal groups,as well as the origin and initial formation of modern terrestrial ecosystem.This review presents a brief introduction of the major discoveries,research history,and current understanding of this biota,and also provides future prospects for studying the Jehol Biota.

The Jehol Biota (Lower Cretaceous, China): new discoveries and future prospects

Continuing work on the paleontology and sedimentology of the Jehol Group(Lower Cretaceous,China)is yielding numerous new insights into the evolution of many Mesozoic plant and animal clades.Nevertheless,many questions remain unanswered regarding Jehol paleoenvironments,paleobiology and paleobiogeography.All of this information will be crucial in providing a detailed reconstruction of this extinct ecosystem.