Early Cretaceous Yixian Formation Research Articles

Septiventeridae, a new and ancestral fossil family of Scarabaeoidea (Insecta: Coleoptera) from the Late Jurassic to Early Cretaceous Yixian Formation

Morphologically, Scarabaeoidea is one of the best-studied groups of beetles. However, the incomplete preservation of presently known fossils is a fundamental problem in the interpretation of extinct species of the superfamily. Wing venation has long been recognized as a valuable character system in taxonomic and phylogenetic analyses. However, to date hind wing features of scarab fossils have not been analysed using geometric morphometrics. A new genus and a new species, Septiventer quadridentatus gen. et sp. nov., is described and illustrated and assigned to a new scarabaeoid family Septiventeridae fam. nov., based on one well-preserved specimen from the Yixian Formation of Liaoning Province, China. The phylogenetic position of Septiventer is inferred based on 68 morphological characters using a cladistic approach. Additionally, based on a geometric morphometric analysis of the hind wing of Septiventer, the structural affinities of 161 scarabs and six outgroup species is analysed, using 261 wing landmarks. Septiventeridae is identified as the sister group of the remaining Scarabaeoidea, with Glaresidae and Trogidae as the next branches. Consequently, it is crucial for an understanding of the early diversification of the superfamily, and for the reconstruction of early evolutionary transformations in the group. Septiventeridae differs strongly from most ‘modern’ lineages in wing shape. However, the structural affinity of the hind wings of Septiventeridae, Glaresidae and Trogidae are robustly supported by the results from morphometrics. This fits well with the phylogenetic hypothesis based on the general character set and strongly suggests that this wing pattern is closest to the scarabaeoid groundplan. The morphological features suggest good flying abilities of Septiventer, that it might have been active during the daytime, processed soft food, and was less active in digging tunnels than extant, more specialized dung beetles. http://zoobank.org/urn:lsid:zoobank.org:pub:B0076219-3F4C-4E3D-8054-7DA855E0D8A4

A new genus of Scolebythidae (Hymenoptera: Chrysidoidea) from the Early Cretaceous of China

A new genus Mirabythus Cai, Shih et Ren, gen. nov. (type species, M. lechrius Cai, Shih et Ren, sp. nov.) and M. liae Cai, Shih et Ren, sp. nov. from the family Scolebythidae are described from the Early Cretaceous Yixian Formation of Huangbanjigou Village, Liaoning Province, northeastern China. These findings extend the existence of Scolebythidae to the Early Cretaceous of China, while providing evidence to support Engel and Grimaldi’s hypothesis that the family was widely distributed throughout the Cretaceous. Our two new species with clear venation also provide a comprehensive understanding of the venational changes from the Early Cretaceous to now. A key to the fossil and extant genera of Scolebythidae is provided.

A new fossil Hybosoridae (Coleoptera: Scarabaeoidea) from the Yixian Formation of China

Hybosoridae is a relatively small family of Scarabaeoidea, including five extant and one fossil subfamily (Ocampo & Ballerio 2006, Nikolajev 2007). Until now, 20 fossil species were known from five subfamilies: Anaidinae, Ceratocanthinae, Hybosorinae, Liparochrinae, and Mimaphodiinae (Ocampo & Ballerio 2006, Krell 2007, Nikolajev 2008, Nikolajev et al. 2010, Nikolajev 2010a, Nikolajev 2010b, Kirejtshuk et al. 2011). In this paper we describe Pulcherhybosorus tridentatus Yan, Bai, & Ren new genus and new species, from a nearly complete and well-preserved fossil. This fossil represents the first record of Hybosoridae from the Early Cretaceous Yixian Formation of Liutiaogou, Inner Mongolia in China. This significant finding tentatively confirms the presence of Hybosoridae during the Mesozoic in what is now China.

Revision of Cypridea (non-marine Ostracoda) from the Early Cretaceous Yixian Formation of the Beipiao–Yixian Basin in western Liaoning, northeast China

The ostracod genus Cypridea Bosquet, which ranges in age from Kimmeridgian to Lower Eocene, frequently occurs abundantly in the Jianshangou and Jinggangshan beds of the Yixian Formation in western Liaoning, northeast China. However, the diversity of species has been considerably overestimated for many years, and this has led to a series of problems concerning taxonomic subdivision and stratigraphic correlation. Based on a large quantity of fossil material and more detailed descriptions of the morphological features, all of the published species of Cypridea from the Jianshangou and Jinggangshan beds are revised in this paper. As a result, 14 species erected previously are merged into three taxa: Cypridea liaoningensis, C. jingangshanensis and C. deplecta.

Phylogeny of the Infraorder Pentatomomorpha based on fossil and extant morphology, with description of a new fossil family from China.

BackgroundAn extinct new family of Pentatomomorpha, Venicoridae Yao, Ren & Cai fam. nov., with 2 new genera and 2 new species (Venicoris solaris Yao, Ren & Rider gen. & sp. nov. and Clavaticoris zhengi Yao, Ren & Cai gen. & sp. nov.) are described from the Early Cretaceous Yixian Formation in Northeast China.Methodology/Principal FindingsA cladistic analysis based on a combination of fossil and extant morphological characters clarified the phylogenetic status of the new family and has allowed the reconstruction of intersuperfamily and interfamily relationships within the Infraorder Pentatomomorpha. The fossil record and diversity of Pentatomomorpha during the Mesozoic is discussed.Conclusions/SignificancePentatomomorpha is a monophyletic group; Aradoidea and the Trichophora are sister groups; these fossils belong to new family, treated as the sister group of remainder of Trichophora; Pentatomoidea is a monophyletic group; Piesmatidae should be separated as a superfamily, Piesmatoidea. Origin time of Pentatomomorpha should be tracked back to the Middle or Early Triassic.

Essential Characteristics of Volcanic Rocks of Yixian Formation and Discussion on Tectonic Setting in Chaoyang Basin, Western Liaoning

Volcanic rocks of Early Cretaceous Yixian Formation were widely distributed in western Liaoning. The Yixian Formation in the Chaoyang basin can be divided into two subcycles from bottom to top. The first subcycle is composed of basalt, basalt andesite and andesite. The second subcycle is composed of trachyandensite and trachyte. The volcanic rocks are characterized by high SiO2, Al2O3, K2O and Na2O, and comparatively low TiO2 components. The volcanic rocks are obviously enriched in incompatible elements (K, Rb, Sr, Zr, Ba, Pb, Li etc.), and depleted in compatible elements (Co, Ni, Cr, V etc.). The volcanic rocks are rich in LREE. There is a slight low Eu negative abnormality and low Ce negative abnormality. Based on t he studies of petrology and geochemistry, volcanic rocks of Yixian Formation belong to the high-K calc-alkaline magmatic serious. Comprehensive study of regional structures and geochemistry of volcanic rocks, the volcanic rocks of Yixian Formation were generated in the environment of lithosphere inhomogeneous extension, as a product of the intraplate orogeny of Yanshan Mountains.

Largest Toothed Pterosaur Skull from the Early Cretaceous Yixian Formation of Western Liaoning, China, with Comments on the Family Boreopteridae

Abstract:A new pterosaur Moganopterus zhuiana gen. et sp. nov. is erected based on a complete skull with lower jaws and anterior cervical vertebrae. It is characterized by much elongated upper and lower jaws with at least 62 total, long, curved teeth with sharp tips, a well developed parietal crest extending posterodorsally, forming an angle of 15 degrees with the ventral margin of the skull, the ratio of length to width of cervical vertebrae greater than 5:1. The skull length is 750 mm, and it is the largest toothed pterosaur found so far in the world. Based on this new pterosaur, the Boreopteridae can be divided into two subgroups: Boreopterinae sub‐fam. nov. and Moganopterinae sub‐fam. nov., which is also confirmed by the phylogenetic analysis.

Sedimentary laminations in the lacustrine Jianshangou Bed of the Yixian Formation at Sihetun, western Liaoning, China

Extremely fine sedimentary laminations of the lacustrine Early Cretaceous Yixian Formation were studied in the excavated Sihetun Fossil Museum section in western Liaoning, China. The section consists mainly of mudstones, shales and layers of volcanic ash. The mudstones and shales are composed of siliciclastic and organic-rich laminae. Most of the laminations are varves that record seasonal climatic changes. Varve thickness measurements show that the sedimentation rate for the majority of the mudstones and shales was 0.2–0.7 mm/year. Quiet, anoxic lacustrine bottom waters were critical for the preservation of the laminations.

The oldest fossil species of the rove beetle subfamily Oxyporinae (Coleoptera: Staphylinidae) from the Early Cretaceous (Yixian Formation, China) and its phylogenetic significance

Oxyporus yixianus Solodovnikov & Yue sp. nov., a new Early Cretaceous fossil rove beetle species, is described from the Yixian Formation of Liaoning Province, China. It is clearly placed in Oxyporus Fabricius, 1775, the extant and only genus of the subfamily Oxyporinae. In addition to the hitherto-known, much younger fossils of Oxyporinae, the significantly older age of this newly discovered species makes the currently accepted phylogenetic hypothesis that Oxyporinae is a basal lineage of the Staphylininae group more plausible. The remarkably modern and specialization-rich morphology of Oxyporus yixianus leads to the assumption that this species exemplifies a rather derived stage of divergence of Oxyporinae from the stem of the Staphylininae group. Divergence of Oxyporinae from the rest of the Staphylininae group lineage may have begun significantly earlier than the Early Cretaceous, and the fungus-associated biology of Oxyporinae is also apparently older than documented by Oxyporus yixianus.

Taphonomy of Early Cretaceous freshwater bivalve concentrations from the Sihetun area, western Liaoning, NE China

The Early Cretaceous Yixian Formation at Sihetun, Beipiao, western Liaoning, northeastern China, is well-known for yielding diverse and excellently preserved fossils of the Jehol Biota. The lower unit of Yixian Formation, dominated by lacustrine deposits, is rich in concentrations of two freshwater bivalves: Sphaerium anderssoni and Arguniella ventricosa. These bivalve concentrations can be divided into three types that comprise either paucispecific A. ventricosa or S. anderssoni, or both bivalves in similar amounts. The lithological, biotic, and taphonomic features of 12 bivalve concentrations are recorded, and the taphonomic signatures (such as shell articulation, size-frequency distribution, and orientation) are analyzed. Autochthonous as opposed to allochthonous bivalve concentrations are discriminated. A very short time-averaging effect is recognized in some concentrations, which was probably caused by seasonal or episodic water-level fluctuations and hypoxia. Three factors operated on the bivalve concentrations before final burial: in-situ reworking, transport, and time-averaging. Although time-averaging of the death assemblages was limited to several years, it is in this way that several generations of the two bivalve species could become preserved together. Reworking of the bivalve concentrations was most likely caused by storm action.

A new ctenochasmatoid pterosaur from the Early Cretaceous Yixian Formation of western Liaoning, China

A new ctenochasmatoid pterosaur, Gladocephaloideus jingangshanensis gen. et sp. nov. from the Yixian Formation of western Laioning Province is erected based on a complete skull and partial postcranial skeleton. It is characterized by following features: about 50 total teeth with sharp tips; small nasoantorbital opening, occupying approximately 13% of the skull length; ratio of prenarial length to skull length approximately 0.63. The diagnoses of the Ctenochasmatoidea and Gallodactylidae are amended based on the new taxon. Gladocephaloideus jingangshanensis is the first gallodactylid pterosaur found in Asia. Its discovery not only provides much more osteological information about the Gallodactylidae but also indicates that the ctenochasmatoid pterosaurs were highly diverse in the Early Cretaceous. The filamentous structures preserved near the dorsal and posterior margins of the posterior portion of the skull and around the neck indicate that it had an epidermal covering and may have been a warm-blooded animal.

New shore bug (Hemiptera, Heteroptera, Saldidae) from the Early Cretaceous of China with phylogenetic analyses

A new genus with a new species of Saldidae, Brevrimatus pulchalifer gen. et sp. n., is described and illustrated. The fossil specimen was found from the Early Cretaceous Yixian Formation of Duolun County, Inner Mongolia, China. Phylogenetic analyses within Saldidae were performed, and the results indicate Brevrimatus pulchalifer gen. et sp. n. should be assigned to the subfamily Chiloxanthinae.

A new fossil silky lacewing genus (Neuroptera, Psychopsidae) from the Early Cretaceous Yixian Formation of China

A new genus and species, Undulopsychopsis alexi gen. et sp. n., is described from the Early CretaceousYixian Formation of western Liaoning Province, China. This genus is probably most closely related to the Asian Cretaceous genus Kagapsychops Fujiyama, 1978. The family affinity of Undulopsychopsis gen. n. is discussed. The genus is preliminarily assigned to Psychopsidae, although it shares some character states with Osmylopsychopidae (e.g., crossveins are very scarce; Rs1 and 1A are multi-branched).

Dynamics of the lacustrine fauna from the Early Cretaceous Yixian Formation, China: implications of volcanic and climatic factors

Pan, Y., Sha, J., Fursich, F.T., Wang, Y., Zhang, X. & Yao, X. 2011: Dynamics of the lacustrine fauna from the Early Cretaceous Yixian Formation, China: implications of volcanic and climatic factors. Lethaia, Vol. 45, pp. 299–314. The taphonomy and palaeoecology of the famous Lower Cretaceous Jehol biota of northeastern China are two of its least resolved aspects. The biota occurs in lacustrine sediments characterized by abundant volcanic ash layers. The general view is that these tuff layers correlate strongly with vertebrate mass mortality events. However, though aquatic invertebrates also suffered mass mortality, in the majority of cases individuals tend to occur on bedding planes of finely laminated sediments, suggesting that each mass mortality event is not related to volcanic activity. Based on data collected in the course of two excavations at Zhangjiagou and Erdaougou, the role of volcanic activity and other factors that could have controlled the dynamics of the fauna were investigated. Cluster analyses of fossil assemblages from both localities show similar results, and eight fossil communities are recognized. In the lacustrine Yixian Formation, frequent and often severe volcanic activity represented by the abundant tuff layers influenced the water quality, causing repeated collapse of the aquatic ecosystem. Bedding planes with remains of the eight different communities were analysed, each recording the community dynamics of a shallow eutrophic lake system that was most probably controlled by fluctuations of oxygen level related to climate. A mortality model, in which oxygen-level fluctuations play the decisive role, is proposed to explain the existence and distribution of the fossil communities, as well as the unfossiliferous layers. □China, Jehol biota, lacustrine community, mass mortality, palaeoclimate, volcanic activity.

New fossil Ochteridae (Hemiptera: Heteroptera: Ochteroidea) from the Upper Mesozoic of north‐eastern China, with phylogeny of the family

Specimens of the velvety shore bugs (Hemiptera: Ochtheridae) occur in the Early Cretaceous Yixian Formation in north‐eastern China. We describe two new genera and three new species –Pristinochterus ovatus Yao, Zhang & Ren sp. nov.,Floricaudus multilocellus Yao, Ren & Shih gen.n. et sp.n. and Angulochterus quatrimaculatus Yao, Zhang & Ren gen.n. et sp.n.– from this deposit. A cladistic analysis based on a combination of fossil and extant taxa, and their morphological characters, clarifies the phylogenetic status of the new fossils and allows the reconstruction of relationships within the family Ochteridae. Two main clades within Ochteridae are recognized from the cladistic analysis: Pristinochterus Yao Cai & Ren and Floricaudus Yao, Ren & Shih gen.n. form a monophyletic lineage; and Angulochterus Yao, Zhang & Ren gen.n. emerges as a sister group to all extant velvety shore bugs. A key to all fossil and extant genera of Ochteridae is provided.

A New Chinese Mesozoic Stick Insect

Renphasma sinica gen. et sp. nov. is described from the Early Cretaceous Yixian Formation in Liaoning. It has the general habitus of the Mesozoic “stick-insects”, with a short thorax, and broad and long tegmina, as long as the hindwings. Its pattern of tegmina venation is typical of the Mesozoic Phasmatodea, also present in the Eocene stick insect family Gallophasmatidae, viz. archaeorthopteran organisation of median and cubital veins. On the other side it has a vomer typical of modern Phasmatodea, both supporting the hypothesis that the Mesozoic, Cainozoic, and modern stick insects belong to the same clade. The pattern of dark and hyaline spots on the wings of Renphasma is probably related to mimicry with plants.

First Description of Fossil Naucoridae (Heteroptera: Nepomorpha) from Late Mesozoic of China

Abstract:Herein the description and illustration of two new fossil genera and species of Naucoridae, Exilcrus cameriferus gen. & sp. Nov. and Miroculus laticephlus gen. & sp. Nov., are provided. Both species were collected from the Late Jurassic to Early Cretaceous Yixian Formation of western Liaoning, China. The complete preservation of the new specimens enable us to determine the characters of the specimens reported here. This finding represents the first record of fossil Naucoridae from China, which includes well‐preserved nymphs. The possibility of a predatory habit of these specimens is discussed.

A second specimen of Manchurochelys manchoukuoensis Endo & Shikama, 1942 (Testudines: Eucryptodira) from the Early Cretaceous Yixian Formation of western Liaoning, China

A second specimen of Manchurochelys manchoukuoensis Endo & Shikama, 1942 (Testudines: Eucryptodira) from the Early Cretaceous Yixian Formation of western Liaoning, China

A new fossil genus of Mesochrysopidae (Neuroptera) from the Early Cretaceous Yixian Formation of China

A new fossil genus of Mesochrysopidae (Neuroptera) from the Early Cretaceous Yixian Formation of China

The First Mesozoic Heterodactyl Bird from China

Dalingheornis liweii gen. et sp. nov., a new enantiornithine bird was collected from the early Cretaceous Yixian Formation in northeastern China. It is the first record of a highly specialized heterodactyl foot in Mesozoic birds. The Y-shaped furcula with short hypocleidum is different from that of other enantiornithines. The minor metacarpal is robust and longer than the major metacarpal. A long bony tail composed of 20 caudal vertebrae with chevrons resembling those of dromaeosaurids and thus, highlighting again the evolutionary relationship between birds and non-avian theropods. Well-preserved alula feathers and a heterodactyl foot provide strong evidence for the arboreal habit of Dalingheornis.