Motani R.,University of California at Davis |
Jiang D.-Y.,Peking University |
Jiang D.-Y.,CAS Nanjing Institute of Geology and Palaeontology |
Chen G.-B.,Anhui Geological Museum |
And 3 more authors.
Nature | Year: 2015
The incompleteness of the fossil record obscures the origin of many of the more derived clades of vertebrates. One such group is the Ichthyopterygia, a clade of obligatory marine reptiles that appeared in the Early Triassic epoch, without any known intermediates. Here we describe a basal ichthyosauriform from the upper Lower Triassic (about 248 million years ago) of China, whose primitive skeleton indicates possible amphibious habits. It is smaller than ichthyopterygians and had unusually large flippers that probably allowed limited terrestrial locomotion. It also retained characteristics of terrestrial diapsid reptiles, including a short snout and body trunk. Unlike more-derived ichthyosauriforms, it was probably a suction feeder. The new species supports the sister-group relationships between ichthyosauriforms and Hupehsuchia, the two forming the Ichthyosauromorpha. Basal ichthyosauromorphs are known exclusively from south China, suggesting that the clade originated in the region, which formed a warm and humid tropical archipelago in the Early Triassic. The oldest unequivocal record of a sauropterygian is also from the same stratigraphic unit of the region. © 2015 Macmillan Publishers Limited. All rights reserved.
Agency: GTR | Branch: NERC | Program: | Phase: Research Grant | Award Amount: 278.08K | Year: 2011
The Earth is a truly remarkable planet. In addition to the physical processes driving plate tectonics, climate and ocean-atmospheric exchange, it supports an extraordinary diversity of living organisms, from microbes to mammals and everything in between. Such wasnt always the case, however, and it is clear that both the planet and its biosphere have evolved - indeed, co-evolved - over deep time. In the past two billion years, by far the most fundamental shift in this co-evolutionary process occurred during the Neoproterozoic (1000 to 542 million years ago), a planetary revolution that culminated in the modern Earth system. The Neoproterozoic begins with a biosphere populated almost exclusively by microbes, and ends in the midst of its greatest ever evolutionary radiation - including the diverse macroscopic and biomineralizing organisms that define the modern biosphere. At the same time, it witnessed the greatest climatic and biogeochemical perturbations that the planet has ever experienced, alongside major palaeogeographic reconfigurations and a deep ocean that is becoming oxygenated for the first time. There is no question that these phenomena are broadly interlinked, but the tangle of causes, consequences and co-evolutionary feedbacks has yet to be convincingly teased apart. In order to reconstruct the Neoproterozoic revolution, we propose a multidisciplinary programme of research that will capture its evolving geochemical and biological signatures in unprecedented detail. Most significantly, these collated data will be assessed and modeled in the context of a co-evolving Earth system, whereby developments in one compartment potentially facilitate and escalate those in another, sometimes to the extent of deriving entirely novel phenomena and co-evolutionary opportunities. Our approach will be guided by three general hypotheses, testable against accruing data and theory: H1) that the enhanced weathering associated with land-dwelling eukaryotes was initiated in the early Neoproterozoic leading to major environmental change, including extreme glaciations and stepwise increase(s) in atmospheric oxygen concentration; H2) that major environmental changes in the mid Neoproterozoic triggered the emergence of animals; and H3) that the late Neoproterozoic-Cambrian radiations of animals and biomineralization were themselves responsible for much of the accompanying biogeochemical perturbation. Primary data for this project will be assembled from field studies of key geological sections in the UK and North China, along with contributed sample sets from Namibia, Spitsbergen and various archived collections. Together, these offer close to comprehensive coverage of the Neoproterozoic - not least, spectacular new surfaces of Ediacaran macrofossils from Charnwood Forest. Collected samples will be analysed to assess associated weathering and climate (Sr, C, O and S isotopes), oceanic redox conditions (Fe speciation and trace metals), nutrient dynamics (P speciation and trace metals) and biological constituents (microfossils, macrofossils and biomarker molecules). These data will be integrated and interrogated through the development of heuristic, spatial and evolutionary models. Beyond its integrative approach, the strength of this proposal lies in the diversity of the contributing researchers. Alongside our own expertise in biogeochemistry, palaeobiology and Earth system modelling, we are very pleased to have attracted world-class project partners in Neoproterozoic stratigraphy, geochronology and biomarker analysis. Further insight will come from our contingent of two PDRAs and three PhD students working across the range of topics and linked via a schedule of regular team meetings. Taken together, we anticipate a fundamentally improved understanding of the Neoproterozoic Earth system and the co-evolutionary interplay between the biosphere and planet.
Zhang J.,CAS Nanjing Institute of Geology and Palaeontology
Palaeontology | Year: 2011
Three nearly complete male specimens of kovalevisargid flies are described as Kovalevisargus macropterus sp. nov., K. brachypterus sp. nov. and Kerosargus sororius sp. nov. (family Kovalevisargidae) from the Callovian-Oxfordian Daohugou biota in Inner Mongolia, China. These extend the range of the family Kovalevisargidae outside of Central Asia for the first time, reveal new morphological details about kovalevisargid flies and offer new evidence for the biostratigraphic correlation of nonmarine sedimentary strata of both the Karabastau and Daohugou Formations. Close similarities in the composition of insect taxa from both entomofaunas imply not only the geological age but also the sedimentary environment at that time being the same, or nearly so. Familial and generic diagnoses of kovalevisargid flies are supplemented based on information derived from these new species. © The Palaeontological Association.
Stiller F.,CAS Nanjing Institute of Geology and Palaeontology
Palaeontology | Year: 2011
The isocrinid sea lily Tyrolecrinus wugangi sp. nov. from uppermost middle to lowermost upper Anisian (lower Middle Triassic) strata of Leidapo near Qingyan, Guizhou Province, south-west China, provides new data on the early phylogeny of the order Isocrinida. The new species is the earliest unequivocal representative of the family Isocrinidae. It predates all other known species of the genus Tyrolecrinus that come from upper Ladinian to Rhaetian strata and also all other known taxa of the Isocrinidae. Nevertheless, its stem is of fully developed isocrinid type and is characteristic of the genus, with consistently synostosial, rarely cryptosymplectial, distal nodal articular facets. These findings indicate that the Isocrinidae evolved prior to the late middle Anisian in the far-eastern part of the Palaeotethys ocean, perhaps in the region forming today's south-west China, and spread to various other regions later in the Middle and Late Triassic. The genus Tyrolecrinus is revised and the new genus Bakonycrinus gen. nov. is erected. © The Palaeontological Association.
Wang J.,CAS Nanjing Institute of Geology and Palaeontology
International Journal of Coal Geology | Year: 2010
Based on investigations of seven stratigraphic sections in the Weibei Coalfield, a typical coal basin in the North China Block, the succession of Late Paleozoic plant macrofossil assemblages from the Benxi (or Penchi in old spelling), Taiyuan, Shanxi, Lower Shihhotse and Upper Shihhotse Formations were redefined. These zones are the: Paripteris spp. .- Linopteris spp. -Conchophyllum richthofenii Assemblage (Benxi Fm.), Neuropteris pseudovata-Lepidodendron posthumii Assemblage (Taiyuan and lower Shanxi Fms.), Emplectopteridium alatum-Emplectopteris triangularis-Cathaysiopteris whitei Assemblage (upper Shanxi and Lower Shihhotse Fms.), Gigantonoclea lagrelii-Fascipteris hallei-Lobatannularia heianensis Assemblage (Upper Shihhotse Fm.). As a result of this biostratigraphic reanalysis, it has become clear that biostratigraphic boundaries do not exactly correlate to lithostratigraphic boundaries as has been thought. The biostratigraphy of the terrestrial deposits in the North China Block were correlated to the IUGS Global Chronostratigraphy. The more precise chronostratigraphic constraints that were obtained as a result of this study make it possible to more precisely correlate the vegetational successions to the concurrent waxing and waning of the Late Paleozoic ice sheets. © 2009 Elsevier B.V.
Zhan R.,CAS Nanjing Institute of Geology and Palaeontology
Integrative zoology | Year: 2014
Paleobiogeographic patterns of the brachiopod faunas before and during the first radiation of the Great Ordovician Biodiversification Event (GOBE) in South China at 6 different localities from the upper Jiangnan Slope to the vast area of the Upper Yangtze Platform show several interesting features. First, the initial brachiopod diversity acme was accompanied by both high origination and extinction rates. Second, no significant changes took place in the taxonomic composition and paleobiogeographic pattern of the brachiopod fauna during the radiation at 5 of the 6 localities studied except the near shore locality, where the first brachiopod radiation was much later than at other localities and was marked by a dramatic increase in endemic constituents. Third, orthides were the predominant brachiopod group during the radiation, and regional brachiopod taxa played a significant role in defining the paleobiogeographic pattern of the radiation. Fourth, the first brachiopod radiation was associated with 3 major pulses of onshore migration from the upper Jiangnan Slope through the central Upper Yangtze Platform to the near shore settings of the platform, with the middle pulse being the most significant. Finally, paleogeographic dispersal took place in both onshore and offshore directions, although the onshore expansion was more prominent; several key brachiopods, such as Paralenorthis, Nocturnellia, Protoskenidioides, Nereidella, Euorthisina and Yangtzeella, first appeared on the upper Jiangnan Slope and later formed distinct, and taxonomically diverse, communities on the Upper Yangtze Platform. The paleogeographic dispersal of brachiopods is considered to be closely related to the tectonic evolution of the Qianzhong Arch. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.
Sha J.,CAS Nanjing Institute of Geology and Palaeontology
Proceedings of the Royal Society B: Biological Sciences | Year: 2010
The non-marine trigonioidid bivalves show five phases of radiation in the Cretaceous of Pal-Asia: pre-Aptian (?Valanginian/Hauterivian-Barremian), Aptian, Albian, Cenomanian and Turonian-Maastrichtian. Their distribution patterns show two distinct palaeo-river systems feeding trigonioidids. Before the Cenomanian, the river system occupied the southwestern-southern-southeastern Pal-Asian continental margin areas. During the Turonian-Maastrichtian, it extended along the line of southcentral China-eastern China-northeastern China-northern China and Mongolia - northwestern China-eastern Fergana Basin of Kyrgyzstan-western Tajikistan Basin of Tajikistan-Tashkent area of Kazakhstan - central Kyzylkum of northern Uzbekistan-Aral Sea area of Kazakhstan. Furthermore, the general trigonioidid distribution pattern demonstrates that Japan was probably attached to part of eastern China and/or Korea during the ?Valanginian/Hauterivian- Cenomanian stages. © 2009 The Royal Society.
Zhang J.,CAS Nanjing Institute of Geology and Palaeontology
Annals of the Entomological Society of America | Year: 2010
One new genus and new species, Sinaxymyia rara gen. et sp. nov., is described. Juraxymyia gen. nov. is proposed for Psocites fossilis Zhang, 2004. The genus and species, Psocites pectinatus (Hong, 1983), is redescribed based on new axymyiids from the Jurassic of China. The systematic positions for Crenoptychoptera decorosa Hao, Dong et Ren, 2009, Crenoptychoptera vulgaris Hao, Dong et Ren, 2009, and Crenoptychoptera vicina Hao, Dong et Ren, 2009 are reassessed, these do belong rather to Axymyiidae than to Eoptychopterinae, Ptychopteridae. All the impressions of male axymyiid flies are the first description in the geological records of Axymyiidae. Establishing homologies between the sclerites of the male genitalia of the Jurassic species described here and recent species of the family is difficult. © 2010 Entomological Society of America.
Zhang J.F.,CAS Nanjing Institute of Geology and Palaeontology
Palaeontology | Year: 2010
Four new Brachycera fossils were collected from the Daohugou biota, China. Among these, two impressions demonstrating peculiar wing venation can be designated as two new species of a new genus (Mostovskisargus portentosus gen. et sp. nov. and M. signatus sp. nov.) referred to a new subfamily Mostovskisarginae (subfam. nov.) within Archisargidae. The third impression belongs to a new species (Calosargus (Pterosargus) sinicus sp. nov.) referred to the subgenus Pterosargus Mostovski, 1997 of Calosargus Mostovski, 1997 within Archisarginae, Archisargidae. It is only the second member of the subgenus Pterosargus worldwide. The fourth impression is a nearly complete fly, Jurassinemestrinus orientalis gen. et sp. nov. referable to Rhagionemestriidae. It reveals new morphological data about rhagionemestriids and extends the geographical distribution of this group beyond Europe and Central Asia during the Mesozoic. A correlation for the archisargid composition of taxa in Daohugou and Karabastau formations is discussed. The age of the fly-bearing strata is briefly reassessed and can be more accurately limited to the Callovian-Oxfordian based on both biostratigraphical correlation and radiometric dating. © The Palaeontological Association.
Sun X.,CAS Nanjing Institute of Geology and Palaeontology |
Yang Q.,CAS Nanjing Institute of Geology and Palaeontology |
Xia X.,CAS Nanjing Institute of Geology and Palaeontology |
Xia X.,University of Ottawa
Molecular Biology and Evolution | Year: 2013
The effective number of codons (Nc) is a widely used index for characterizing codon usage bias because it does not require a set of reference genes as does codon adaptation index (CAI) and because of the freely available computational tools such as CodonW. However, Nc, as originally formulated has many problems. For example, it can have values far greater than the number of sense codons; it treats a 6-fold compound codon family as a single-codon family although it is made of a 2-fold and a 4-fold codon family that can be under dramatically different selection for codon usage bias; the existing implementations do not handle all different genetic codes; it is often biased by codon families with a small number of codons. We developed a new Nc that has a number of advantages over the original Nc. Its maximum value equals the number of sense codons when all synonymous codons are used equally, and its minimum value equals the number of codon families when exactly one codon is used in each synonymous codon family. It handles all known genetic codes. It breaks the compound codon families (e.g., those involving amino acids coded by six synonymous codons) into 2-fold and 4-fold codon families. It reduces the effect of codon families with few codons by introducing pseudocount and weighted averages. The new Nc has significantly improved correlation with CAI than the original Nc from CodonW based on protein-coding genes from Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Escherichia coli, Bacillus subtilis, Micrococcus luteus, and Mycoplasma genitalium. It also correlates better with protein abundance data from the yeast than the original Nc. © 2012 The Author.