Yanliao Biota Research Articles

Jurassic–Cretaceous boundary theropod tracks from the slope of the Fallen Feng, Chicheng, China: review and new observations

ABSTRACT The Tuchengzi Formation represents a Jurassic – Cretaceous boundary regional lithological unit that bridges the temporal gap between the Yanliao biota and the Jehol biota. Tetrapod tracks represent the most significant vertebrate fossil records in the formation, and can be employed to supplement the Late Jurassic fauna and palaeoecological data from northern China. Here, we present a re-analysis of the theropod tracks from the Luofenggou site in northern Hebei Province, utilising an additional 3D model and a locomotory analysis to provide further insights into the ecological context. A morphological analysis indicates that these tracks are more similar to Grallator than to the previously proposed Therangospodus. The latter is diagnosed by coalesced, elongate, oval digital pads lacking a separation in distinct phalangeal pads, whereas these are clearly defined in the presented Tuchengzi material. They can therefore be assigned to the widespread G. ssatoi ichnospecies from the Tuchengzi Formation, although they are longer and more variable in size than other G. ssatoi. A general consideration of speed-related locomotive parameters, trackway morphology, and superposition allows for the speculation of the existence of cooperative or predatory relationships between theropod trackmakers that were differentiated by size or stages of ontogeny, but had similar foot structures.

Late Jurassic–Early Cretaceous dinosaur track assemblages from northwestern Hebei Province, China: Implications for paleoenvironment and paleoecology

The relationship between the Middle–Late Jurassic Yanliao Biota and the Early Cretaceous Jehol Biota has long been unresolved due to an approximately 20 Ma “vertebrate fossil gap”. However, a large number of dinosaur tracks have been reported from the Tuchengzi/Houcheng Formation in northern Hebei–western Liaoning, which occupies the stratigraphic position between the Yanliao Biota and the Jehol Biota. This paper presents new discoveries of diverse dinosaur track assemblages from the Upper Jurassic–Lower Cretaceous Houcheng Formation in the Shangyi Basin, northwestern Hebei Province, China. Based on the ichnological analyses, tracks are assigned to the sauropod Parabrontopodus, theropod Grallator, Anchisauripus, Eubrontes, and Therangospodus. The theropod tracks were likely produced by small-sized feathered theropod dinosaurs (Coelurosauria) that thrived in both the Yanliao Biota and the Jehol Biota. These findings imply that these two biotas evolved successively, without evidence of a complete turnover or extinction of biotas. Sedimentological studies of the tracksites reveal their occurrence in diverse sedimentary environments, including braided sandbar, floodplain, and deltaic plain. The coexistence of highly diverse dinosaur tracks with various preservation environments indicates that the living environment during that time was relatively comfortable. The increased diversity of dinosaur tracks in the upper part of the Houcheng Formation closely aligns with the intense volcanic activity of the Zhangjiakou Formation in northwestern Hebei Province. This suggests that volcanic activity likely served a crucial function in the proliferation of the dinosaur fauna in the Shangyi Basin and northern North China during the earliest Cretaceous.

Stratigraphic and U-Pb zircon age constraints on the timing of the Yanliao Biota in northern China

The Yanliao Biota from northern China is one of the most famous Mesozoic terrestrial lagerstätten in the world, with well-preserved fossil records in the Jurassic volcanic-sedimentary Ningcheng and Jianchang basins. However, the temporal evolution of the Yanliao Biota remains controversial, mainly due to the confusing stratigraphic framework and the unclear age of fossiliferous deposits in the Ningcheng basin. To address this issue, we carried out detailed field investigations and secondary ion mass spectrometry (SIMS) U-Pb age dating of zircons on fossiliferous and related strata in the southern part of the Ningcheng basin. The Jurassic infill of this area is composed of, in ascending order, fossil-bearing tuffaceous clastic rocks (unit 1), andesite and pyroclastic rocks (unit 2), fossil-bearing clastic rocks interlayered with minor volcanic rocks (unit 3), and andesite and pyroclastic rocks (unit 4). Integration of stratigraphic and geochronological data indicates that the Yanliao Biota in the Ningcheng basin appeared no later than ca. 163 Ma and lasted until ca. 156 Ma. A comparison with other analogous basins in northern China (e.g., the Luanping, Jianchang, and Beipiao basins) leads to the conclusion that the Yanliao Biota evolved in two phases and lasted for more than 11 m.y.: the first phase from ca. 167 Ma to ca. 163 Ma in the middle Bathonian to middle Callovian, followed by the second phase between ca. 161 Ma and ca. 156 Ma in the lower and middle Oxfordian.

Clam shrimp assemblage from Daohugou: A link correlating northern Hebei and western Liaoning

The clam shrimp species, Triglypta pingquanensis Wang, 1984, is reported in the Middle Jurassic Daohugou beds from two localities in Inner Mongolia. The species is predominant in the Middle Jurassic Longmen Formation in Yingzi Village, Pingquan City, northern Hebei. This discovery significantly strengthens the correlation between the Haifanggou and Longmen formations. The clam shrimp of the Haifanggou and Longmen formations are dominated by T. haifanggouensis Chen, 1976 and T. pingquanensis, respectively. The clam shrimp assemblage from the Daohugou beds serves as a crucial link for correlating the Middle Jurassic in northern Hebei and western Liaoning, and it represents the early assemblage of the Yanliao biota. Moreover, a new species, T. hebeiensis Liao & Huang sp. nov., is described in the uppermost layer of the Longmen Formation in this study.

A new species of Cicadocoris (Hemiptera, Coleorrhyncha, Progonocimicidae) from the Middle Jurassic of the Jiyuan Basin, China.

Progonocimicids are one of key representatives from the Middle-Late Jurassic Daohugou biota, the early assemblage of the Yanliao biota. Here we describe a new progonocimicid species, Cicadocoris henanensis sp. nov., from the Middle Jurassic Jiyuan Basin in central China. This not only represents a novel case indicating the abundance of progonocimicids during the Jurassic but also provides additional evidence substantiating the stratigraphic correlation between the Yangshuzhuang Formation in the Jiyuan Basin and the Haifanggou Formation in the Yanliao Region.

New Jurassic protopsyllidiids from the Yan’an Formation, North China (Insecta: Hemiptera)

The Middle-Late Jurassic Yanliao biota is a significant paleoecosystem for the understanding of the evolution of Life during the Mesozoic. The origin, distribution, and geology of the Yanliao biota are poorly understood to date. Here we describe and illustrate two new species of protopsyllidiids, namely Sinopsocus yananensis sp. nov. and Subaphidulum sinica sp. nov. from the Middle Jurassic Yan’an Formation near Yan’an City, Shaanxi Province, North China. S. yananensis sp. nov. closely resembles the type species Sinopsocus oligovenus from the Haifanggou Formation at Beipiao City, West Liaoning, Northeast China. The new discoveries not only increase the diversity of Mesozoic protopsyllidiids but also provide thread for understanding the origin of the Yanliao biota.

A chronostratigraphic and biostratigraphic framework for the Yanliao Biota of northeastern China: Implications for Jurassic terrestrial ecosystems and evolution

The terrestrial Yanliao Biota in northeastern China represents a Jurassic biodiversity hotspot. Abundant and diverse fossils include the oldest known representatives of several groups of plants, invertebrates, and vertebrates that thrived in a forest ecosystem under a humid and warm climate. Since the early 21st century, discoveries associated with the Yanliao Biota have significantly improved our understanding of Jurassic terrestrial ecosystems. However, a robust chronostratigraphic framework is required to calibrate the biota with key evolutionary events and to improve understanding of possible links between evolution and tectonism. In this paper, we report novel 40Ar/39Ar ages for two tuff layers (161.4 ± 0.8 Ma and 161.6 ± 0.6 Ma) positioned directly above the less-studied but salamander fossil-rich beds in Reshuitang, near Lingyuan, Liaoning Province, China. These new age data improve knowledge of the timing of diversification of early salamanders. We also review all reported age data and summarize significant fossils from classic Yanliao outcrops. Our study indicates that the Reshuitang fossil beds were deposited slightly later than the well-known Daohugou fossil beds situated ∼15 km away in Inner Mongolia and somewhat earlier than the Linglongta fossil beds in western Liaoning Province. These findings advance understanding of the Jurassic world during an episode of pronounced climatic warming.

A new euharamiyidan, Mirusodens caii (Mammalia: Euharamiyida), from the Jurassic Yanliao Biota and evolution of allotherian mammals

Abstract Allotheria are an extinct group of mammaliaforms that originally comprised multituberculates, to which ‘haramiyidans’ and gondwanatherians were later added. Phylogenetic relationships of allotherians have remained controversial since the first reports of the allotherian fossils in the 1800s. Here we report a new euharamiyidan based on a skeletal specimen from the Jurassic Daohugou phase of the Yanliao Biota, China. The superb specimen preserves impressions of differentiated hairs. The pes with impressions of toe skin and claw sheath represents the first such evidence in Mesozoic mammaliamorphs. The remarkable tooth morphologies surpass in complexity any Mesozoic mammals previously known. Phylogenetic analyses place the new species within euharamiyidans from Eurasia and support euharamiyidans, multituberculates, and gondwanatherians as a tripartite monophyletic Allotheria within mammals. This clade is supported not only by their similar molar pattern, but also by many shared derived features of the dental system recognized from discoveries during the last two decades. Allotherians and therians represent the two most successful groups of mammals that are characterized by distinct dental systems. They originated at the latest in the Late Triassic and became diversified in the Middle Jurassic, representing two directions of ecomorphological adaptation during early evolution of mammals.

Temporal framework for the Yanliao Biota and timing of the origin of crown mammals

Establishing the temporal sequence of the Middle-Late Jurassic Yanliao Biota is essential as it anchors the timing of many key evolutionary innovations in vertebrates. Lack of sufficiently reliable high-precision ages of fossil-bearing horizons hinders our ability to reconstruct the tempo and mode of vertebrate evolution. Here, we frame a temporal sequence of Yanliao Biota with precise age constraints for iconic vertebrates, proposing that the major vertebrate-bearing strata span from 164 Ma to 157 Ma in age. The increasing ecological diversity of mammaliaforms is well illustrated by the Middle-Late Jurassic Yanliao Biota and Early Cretaceous Jehol Biota. Incorporation of the updated temporal frameworks in Bayesian tip-dated mammaliaform phylogeny reveals that Triassic haramiyidans are separate from Jurassic taxa and unrelated to crown Mammalia. Tip-dated phylogeny supports a long-fuse model for mammal evolution, featured by a Late Triassic root and Middle-Late Jurassic interordinal diversification of crown Mammalia, showing consistency with molecular-based timetrees in divergence timing.

Volcanic phosphorus supply boosted Mesozoic terrestrial biotas in northern China

The Mesozoic terrestrial Jehol Biota of northern China exceeds the biomass and biodiversity of contemporaneous Lagerstätten. From 135 to 120 Ma, biotic radiation may have responded to the peak destruction of the North China Craton. However, the direct mechanistic link between geological and biological evolution is unclear. Phosphorus (P), a bio-essential nutrient, can be supplied by weathering of volcanics in terrestrial ecosystems. The middle–late Mesozoic volcanic-sedimentary sequences of northern China are amazingly rich in terrestrial organisms. Here we demonstrate episodic increases in P delivery, biological productivity, and species abundance in these strata to reveal the coevolution of volcanism and terrestrial biotas. A massive P supply from the weathering of voluminous volcanic products of craton destruction thus supported a terrestrial environment conducive to the high prosperity of the Jehol Biota. During the nascent stage of craton destruction, such volcanic-biotic coupling can also account for the preceding Yanliao Biota with relatively fewer fossils.

Linglongtaestheria (Spinicaudata) from the Upper Jurassic of Qinglong, Hebei Province, northeastern China

We report a new clam shrimp species, Linglongtaestheria qinglongensis n. sp., discovered from the Tiaojishan Formation at Zhuanshanzi, Qinglong Manchu Autonomous County, Hebei Province. The new species is characterized by its distinct ornamentation of the growth bands: 1) with fine polygonal reticulations near the umbo; 2) puncta developed in the middle and posterior parts of the carapace; 3) punctate reticulations developed in the anterior marginal and antero-ventral parts of the carapace. The occurrence of the genus Linglongtaestheria from the Zhuanshanzi fossil beds suggests its correlation with the Linglongta fossil beds of the Upper Jurassic Tiaojishan Formation at Daxishan Village, Jianchang County, western Liaoning, representing the younger assemblage of the Yanliao Biota, distinguished from the older Daohugou assemblage, the first phase of the Yanliao Biota.

Revisiting the Late Jurassic adakitic rocks in the Yanshan fold and thrust belts, North China Craton: Partial melts from thickened continental crust?

An integrated study of zircon U-Pb ages and Hf-O isotopes, whole rock and apatite geochemistry, and whole rock Sr-Nd-Hf isotopes were conducted for the Jurassic adakitic volcanic rocks from the Tiaojishan Formation in the Yanshan Fold and Thrust Belt (YFTB) of the North China Craton, to investigate their genesis, with attention to the role of crust thickness in achieving the adakitic traits. Zircon U-Pb dating gives eruption ages of 162–158 Ma for these rocks. These rocks have variable SiO 2 (55.7–68.1 wt%) and MgO (0.35–4.0 wt%), and adakitic trace element signatures including high Sr/Y (27.9–100) and (La/Yb) N ratios (9.6–27.6). Chemical variations in whole rock and apatite suggest a feldspar-dominated fractional crystallization, superimposed by variable mineral accumulation on whole rock compositions. Together with isotopic compositions that include evolved whole rock ( 87 Sr/ 86 Sr) i = 0.70447–0.70591, ε Nd (t) = −17.5 to −12.1, and ε Hf (t) = −22.2 to −11.2, and zircon ε Hf (t) = −26.8 to −11.2 and δ 18 O = 5.7–7.0 ‰, we attribute these rocks are sourced from mafic lower continental crust. By comparing the trace element signatures between the examined samples and modern continental arc magmatic rocks formed at variable crustal thickness, it is suggested that these rocks are most likely originated from a thickened crust. A further estimate based on whole rock Sr/Y and La/Yb gives a crust thickness of 56 ± 7 km. The crust thickening and associated uplift of the YFTB could be attributed to the westward subduction of the Paleo-Pacific plate. This led to a high altitude (∼3.8 ± 0.9 km) and cool climate habitat (a mean annual paleotemperature of 7 ± 7 °C) for the Yanliao Biota lived therein during this period, which may have played an important role in the earliest appearance of the feathered characteristic of dinosaurs. • A thickened lower continental crust source is responsible for the volcanic rocks. • Crust thickening and uplift are related to the subduction of the Paleo-Pacific plate. • Uplift-induced cooling may be important for the appearance of feathered dinosaurs.

New allotherian specimens from the Middle Jurassic Woodeaton Quarry (Oxfordshire) and implications for haramiyidan diversity and phylogeny

We report new allotherian tooth specimens from the Middle Jurassic White Limestone Formation at Woodeaton Quarry (Oxfordshire), United Kingdom. Two teeth are assigned to Kermackodon (=Eleutherodon) oxfordensis, a taxon whose original generic name (Eleutherodon) was preoccupied and is here assigned to Kermackodon to form a new binomial combination for the species name. Butlerodon quadratus gen. et sp. nov. (family Kermackodontidae), based on 13 cheek teeth and incisors, shows dental features intermediate between K. oxfordensis and the Late Triassic “haramiyidans” (Haramiyavia and Thomasia). Woodeatonia parva gen. et sp. nov. (family indeterminate), based on three teeth, is characterized by its small size. A second upper molar from a multituberculate is identified as Hahnotherium cf. H. antiquum, which possesses characters typical for multituberculates but distinctive from “haramiyidans”. The allotherian teeth from the Forest Marble Formation, previously assigned to the haramiyidans “Eleutherodon”, “Millsodon” and “Kirtlingtonia”, and the multituberculate Kermackodon, are reinterpreted as teeth from different upper or lower dental loci of the same haramiyidan species K. oxfordensis, which result in significant taxonomical modification of these allotherians (“haramiyidans” and multituberculates). Given that Kermackodon has been regarded as a transitional form between multituberculates and “haramiyidans”, these taxonomical modifications would affect interpretation of early evolution of allotherians. In a comparison of molars in known “haramiyidans”, we delve into their occlusal patterns and cusp homologies that have been controversial but pivotal for understanding evolution of allotherians. We further conduct the first phylogenetic analysis of haramiyidan species. The European Late Triassic species form the stem-ward taxa of “haramiyidans” and the Jurassic species from the United Kingdom are grouped with arboroharamiyids from the Yanliao Biota, China, and nested in “haramiyidans”. http://zoobank.org/urn:lsid:zoobank.org:pub:38F1FB5A-17A2-498F-B1FD-38D975548201 http://zoobank.org/urn:lsid:zoobank.org:act:FF5ADA10-C044-4541-ADA6-54448F17C673 http://zoobank.org/urn:lsid:zoobank.org:act:6E59071A-56DF-43D2-A140-2860465BFECA http://zoobank.org/urn:lsid:zoobank.org:act:CA2EE3CF-951C-450A-879D-2AE438F6BB2A http://zoobank.org/urn:lsid:zoobank.org:act:6B26D9C3-9FC3-4517-A1EF-51822067F970

A new structurally preserved fossil umbrella pine from the Jurassic of East Asia

The Sciadopityaceae are today a monotypic and relict family of the Coniferales, restricted to Japan with an endemic species of Sciadopitys verticillata Sieb. et Zucc., known as umbrella pine. Megafossil remains assigned to the Sciadopityaceae have been reported from various parts of the boreal hemisphere. However, structurally preserved fossil wood of the Sciadopityaceae is poorly documented. Here we present an anatomically preserved fossil wood of the Sciadopityaceae from the Jurassic of East Asia. A new fossil wood Zhangoxylon yanliaoense gen. et sp. nov. is proposed for the specimens, which are anatomically characterized by a heterogeneous pith, endarch primary xylem, and special secondary xylem. The anatomical structures of the new genus are similar to those of the living Sciadopitys except for the type of radial pitting. The present specimen has an araucarian radial pitting, while that of the living Sciadopitys is abietinean. Therefore, Zhangoxylon gen. nov. from the Middle to Late Jurassic (Callovian to Kimmeridgian) in western Liaoning may represent the Sciadopitys‐like petrified wood which bears pith and primary xylem. This new fossil, so far, the best‐known fossil wood of the family Sciadopityaceae, sheds light on the early evolutionary history of the family Sciadopityaceae, and contributes to a better understanding of the palaeoenvironment of the Jurassic Yanliao Biota in East Asia.

A Preliminary Review of Dinosaur Track Assemblages from the Tuchengzi Formation in North China

In northern China, mainly within Western Liaoning, Northern Hebei and Beijing, vertebrate skeletons from the Tuchengzi Formation (Upper Jurassic to Lower Cretaceous) are scarce. However, a large number of new dinosaur track discoveries have made in past 10 years. So far, a total of 19 dinosaur track sites have been found in the Tuchengzi Formation, collectively containing 2,637 individual tracks and representing at least 2,091 trackmakers. This track record has become an important sample for understanding the Tuchengzi dinosaur fauna. The abundant Tuchengzi track record includes six non-avian theropod ichnogenera (Asianopodus, Eubrontes, Grallator, Menglongipus, Therangospodus, and Velociraptorichnus), three bird ichnogenera (Aquatilavipes, Pullornipes, and Koreanaornis), two sauropod ichnogenera (Brontopodus and cf. Parabrontopodus isp.), and a possible ornithopod ichnogenus (cf. Dinehichnu). This assemblage is saurischian-dominated, which is consistent with most Jurassic and Cretaceous track sites in China. The presence of deinonychosaurian tracks is consistent with the rich skeletal record from the Yanliao Biota or Jehol Biota, and the bird tracks are consistent with the record of shorebirds in Jehol Biota. The existence of ornithopod tracks is doubtful and needs further discoveries to be confirmed.

Two emetolite-pterosaur associations from the Late Jurassic of China: showing the first evidence for antiperistalsis in pterosaurs.

Knowledge about the pterosaur diet and digestive system is limited, and there is little direct evidence in the fossil record. Here, we report two specimens of the wukongopterid Kunpengopterus sinensis, a juvenile and an adult, from the Late Jurassic Yanliao Biota of China with associated bromalites. Both of these concentrations are identified as emetolites, fossilized gastric pellets. These pellets contain scales of an unnamed palaeonisciform fish, confirming the pterosaur was a piscivore. It probably vomited the pellets, indicating the presence of two-part stomachs and efficient antiperistalsis in both juveniles and adults. Comparing the ganoid scales found in the pellets with those of complete fishes, it was possible to determine that the prey of the smaller pellet is an average-sized individual, while the prey of the larger pellet represents a large specimen. Kunpengopterus sinensis might have preyed on the same fish during ontogeny, with adults being able to feed on larger individuals. This article is part of the theme issue 'The impact of Chinese palaeontology on evolutionary research'.

Clam shrimp of the Middle–Late Jurassic Yanliao Biota in China

Abstract Fossil clam shrimp are widely distributed in the Jurassic terrestrial sediments of China. The Yanliao Biota, consisting of abundant and diverse well-preserved fossil vertebrates and invertebrates, is one of the most famous Mesozoic terrestrial biotas from around the world. The border area between western Liaoning, northern Hebei and southeastern Inner Mongolia is the core area for the biota. Clam shrimp are abundant and widely distributed in different localities in the area. Research on these clam shrimp has been conducted for decades. However, with advances in research instruments and technologies, great changes have taken place in the taxonomy of these clam shrimp and, consequently, our understanding of the biota in recent years. The fossil content of the Yanliao Biota in the core area consists of an early assemblage and a late assemblage, which are characterized by distinctly different clam shrimp. These clam shrimp all belong to one family: Triglyptidae. Members of the family are widely distributed in the Bathonian to Kimmeridgian of northeastern, northwestern and southwestern China.

True hopper fossils (Fulgoromorpha and Cicadomorpha) in the Jurassic to Cretaceous of eastern Asia and their evolutionary implications

Abstract True hoppers, consisting of Fulgoromorpha and Cicadomorpha, are plant feeders with very high species-level diversity. A large number of true hopper fossils have been reported from eastern Asia, especially from the Middle to Late Jurassic Yanliao Biota, the Early Cretaceous Jehol Biota and mid-Cretaceous Kachin amber in the last two decades. Herein, true hoppers from the Jurassic and Cretaceous of eastern Asia are reviewed, and combining palaeontological data from other regions of the world and recent advances of molecular studies, the evolutionary history of true hoppers in the mid–late Mesozoic is discussed. Permocicada beipiaoensis Wang, 1987 and Archijassus plurinervis Zhang, 1985 are here excluded from Prosboloidea and Archijassidae, respectively. By the end of 2020, a total of 203 species with definite systematic position had been documented in the Jurassic and Cretaceous of eastern Asia (China, Myanmar, Siberia, Mongolia, Japan and Korea), and were attributed to 116 genera in 22 families and 7 superfamilies. Available fossil data suggest that true hopper components strongly changed in the Cretaceous: primitive groups reduced and went extinct successively, and the origin and/or early diversification of most lineages (family or subfamily level) occurred, likely owing to the displacement of host-plants in the angiosperm floristic revolution.

New species and material of Hagloidea (Insecta, Ensifera) from the Yanliao biota of China.

A new species of Cyrtophyllitinae, Archaboilus polyneurussp. nov. Gu, Yue & Ren, is described from the Middle Jurassic Jiulongshan Formation, Daohugou Village, Inner Mongolia, China. The species is characterized by its ScA reaching the anterior wing margin at the level of the divergence of M+ CuA, distally branched RP, lengths of free CuA and free M equal, and numerous branches of CuA + CuPaα. A new fossil of Liassophyllum caii Gu & Ren, 2012 is described which increases knowledge of its wing venation and indicates that Liassophyllum should be assigned to the Tuphellidae.

Jurassic scorpionflies (Mecoptera) with swollen first metatarsal segments suggesting sexual dimorphism

BackgroundSexual dimorphism is widespread in insects. The certain specialized structures may be used as weapons in male–male combats or as ornaments to enhance mating opportunities.ResultsWe report striking swollen first tarsal segments in two families, four genera and six species of scorpionflies from the Middle Jurassic Yanliao Biota of Northeastern China. Swollen tarsal segments are restricted to male specimens and to hind leg tarsi. The geometric morphometric analyses reveal that the degree of swelling within the orthophlebiid species possessing swollen first metatarsal segments is species-specific, which can be used as a diagnostic character for taxonomic and phylogenetic studies.ConclusionsThe new findings indicate that swollen first metatarsal segments are relatively common in the family Orthophlebiidae during the Middle Jurassic. The tarsal swellings are considered to be sexually dimorphic, potentially associated with sexually display by males and/or camouflage of a “nuptial gift” in the mating process.