Late Jurassic salamanders from northern China

With ten extant families, salamanders (urodeles) are one of the three major groups of modern amphibians (lissamphibians). Extant salamanders are often used as a model system to assess fundamental issues of developmental, morphological and biogeographical evolution. Unfortunately, our understanding of these issues has been hampered by the paucity of fossil evidence available to assess the early history of the group. Here we report the discovery of an extraordinary sample of salamander fossils, some with rare soft-tissue impressions, from the Upper Jurassic of China. With over 500 articulated specimens, this assemblage documents the morphological diversity of early urodeles and includes larvae and adults of both neotenic and metamorphosed taxa. Phylogenetic analysis confirms that these salamanders are primitive, and reveals that all basal salamander clades have Asian distributions. This is compelling evidence for an Asian origin of Recent salamanders, as well as for an extensive and early radiation of several major lineages. These discoveries show that the evolution of salamanders has involved phylogenetic and ecological diversification around a body plan that has remained fundamentally stable for over 150 million years.     

Using the fossil record to estimate the age of the last common ancestor of extant primates

Divergence times estimated from molecular data often considerably predate the earliest known fossil representatives of the groups studied. For the order Primates, molecular data calibrated with various external fossil dates uniformly suggest a mid-Cretaceous divergence from other placental mammals, some 90 million years (Myr) ago, whereas the oldest known fossil primates are from the basal Eocene epoch (54-55 Myr ago). The common ancestor of primates should be earlier than the oldest known fossils, but adequate quantification is needed to interpret possible discrepancies between molecular and palaeontological estimates. Here we present a new statistical method, based on an estimate of species preservation derived from a model of the diversification pattern, that suggests a Cretaceous last common ancestor of primates, approximately 81.5 Myr ago, close to the initial divergence time inferred from molecular data. It also suggests that no more than 7% of all primate species that have ever existed are known from fossils. The approach unites all the available palaeontological methods of timing evolutionary events: the fossil record, extant species and clade diversification models.     

西藏申扎地区石炭-二叠纪岩石地层划分之我见

岩石地层单位是根据地层的岩性特征划分的地层单位,组是岩石地层的基本单位.西藏申扎德日昂玛-下拉和昂杰剖面石炭-二叠系发育,该地区石炭、二叠系的岩石地层单位都是在这两个剖面上建立.然而,其中的一些岩石地层单位的建立是根据地层中的化石组合而不是据其岩性特征,不符合多重地层划分的原则.该文对申扎地区石炭-二叠纪岩石地层系统提出了一些见解,并简要讨论了石炭-二叠系界线.     

Whole fossil plants of <Emphasis Type="Italic">Ephedra</Emphasis> and their implications on the morphology,ecology and evolution of Ephedraceae (Gnetales)

Although there are many reports of fossil Ephedraceae,whole plant fossil record remains rare.Due to a lack of trust on partially preserved fossil materials,scholars working on molecular clock proposed a recent origin of Ephedra and cast doubt on the earlier origin time of Ephedraceae.To better the understanding on this interesting group,here we report whole plants of Ephedra hongtaoi sp.nov.(Ephedraceae,Gnetales) from the Yixian Formation (Early Cretaceous) in western Liaoning,China.These whole plants of Ep...     

Phylogeny and divergence time estimation of cheilostome bryozoans based on mitochodrial 16S rRNA sequences

The mitochondrial 16S rDNA sequences of 40 species of cheilostome bryozoans including those of 24 species newly determined were used to reconstruct the phylogenetic tree using neighboring-joining and maximum-parsimony methods. By applying molecular clock technique on the basis of the appropriate phylogeny and the fossil record, the divergence times of the two main cheilostome groups, Anasca and Ascophora sensu stricto, were estimated. The results show that the molecular phylogeny of the higher taxonomic groups (superfamilies and higher taxa) of cheilostome bryozoans is mostly in conflict with the morphology-based phylogenetic trees; the divergence of the extant groups of Anasca and those of Ascophora sensu stricto is estimated to have happened about 263 Ma (Permian Guadalupian Epoch) and 183 Ma (Early Jurassic), respectively.     

古生代植物与昆虫相互作用的化石证据——探秘深时陆地生态系统的窗口

 植物与昆虫是当今陆地生态系统的重要组成部分,两者之间的相互关系为认识陆地生态系统结构和功能提供独一无二的信息。古生代是植物和昆虫起源和早期演化的关键地质时期,然而由于缺乏对该时期化石材料的系统研究,植物和昆虫之间的相互关系及其协同演化过程还存在许多未解之谜。对二叠纪晚期（约2.53亿年前）植物茎干中甲虫蛀孔的详细解剖学研究,证实当时蛀木甲虫利用真菌实现个体发育过程中食性的转变,而且蛀木甲虫可能存在初步的社会分工,并生活在复杂的生态网络中;进一步研究显示晚二叠世蛀木甲虫或对松柏类植物引起严重的虫灾。当前研究表明,渗矿化植物化石标本在探索地质历史时期动植物相互作用方面具有巨大研究潜力,可为深时陆地生态系统的重建和演化提供宝贵信息。     

Fossil evidence for an ancient divergence of lorises and galagos

Morphological, molecular, and biogeographic data bearing on early primate evolution suggest that the clade containing extant (or 'crown') strepsirrhine primates (lemurs, lorises and galagos) arose in Afro-Arabia during the early Palaeogene, but over a century of palaeontological exploration on that landmass has failed to uncover any conclusive support for that hypothesis. Here we describe the first demonstrable crown strepsirrhines from the Afro-Arabian Palaeogene--a galagid and a possible lorisid from the late middle Eocene of Egypt, the latter of which provides the earliest fossil evidence for the distinctive strepsirrhine toothcomb. These discoveries approximately double the previous temporal range of undoubted lorisiforms and lend the first strong palaeontological support to the hypothesis of an ancient Afro-Arabian origin for crown Strepsirrhini and an Eocene divergence of extant lorisiform families.     

中国凹耳蛙用高频声进行种内通讯

与绝大多数蛙不同,凹耳蛙发出高频叫声,以避开强环境噪声的掩蔽;雌蛙排卵前产生高频求偶声,诱发雄蛙以超精确度趋近雌蛙;雄蛙能自主开闭咽鼓管,以调谐高频听觉。凹耳蛙进化的这些特征是对嘈杂生境的适应,在其他两栖动物中尚未发现,这对研究动物声通讯进化很有价值。鉴于凹耳蛙为中国特有,数量稀少,分布地区狭窄,建议将它列为稀有濒危物种予以保护。     

新疆吐鲁番桃树园晚二叠世双壳类化石及其时代

系统研究了新疆吐鲁番桃树园晚二叠世梧桐沟组双壳动物化石，讨论了化石组合特点及地质时代。根据化石组合内容、岩性和沉积特征，以及剖面结构，认为梧桐沟组的时代应为晚二叠世     

Phylogenetic relationships and divergence times of the family Araucariaceae based on the DNA sequences of eight genes

Araucariaceae is one of the most primitive families of the living conifers, and its phylogenetic relationships and divergence times are critically important issues. The DNA sequences of 8 genes, i.e., nuclear ribosomal 18S and 26S rRNA, chloroplast 16S rRNA, rbcL, matK and rps4, and mitochondrial coxl and atpl, obtained from this study and GenBank were used for constructing the molecular phylogenetic trees of Araucariaceae, indicating that the phyiogenetic relationships among the three genera of this family should be （（Wollemia, Agathis）, Araucaria）. On the basis of the fossil calibrations of Wollemia and the two tribes Araucaria and Eutacta of the genus Araucaria, the divergence time of Araucariaceae was estimated to be （308± 53） million years ago, that is, the origin of the family was in the Late Carboniferous rather than Triassic as a traditional view. With the same gene combination, the diver- gence times of the genera Araucaria and Agathis were （246 ± 47） and （61 ±15） Ma, respectively. Statis- tical analyses on the phylogenetic trees generated by using different genes and comparisons of the divergence times estimated by using those genes suggested that the chloroplast matK and rps4 genes are most suitable for investigating the phylogenetic relationships and divergence times of the family Araucariaceae.     

石珊瑚起源的形态学和分子系统学研究

石珊瑚是现代最重要的造礁动物,在地质史的过去和现在都非常重要。石珊瑚的起源一直是珊瑚研究中颇有争议的重大问题：石珊瑚究竟是起源于古生代的皱壁珊瑚、一种石珊瑚形珊瑚,还是一类软体海葵,目前还很难下定论。建立在现代石珊瑚及其化石的形态学特征基础上的传统研究手段和新兴的分子系统学分析手段,是研究石珊瑚起源问题的2种主要方法。用分子生物学方法测定了珊瑚的18S rDNA,构建了珊瑚纲珊瑚的系统发育树,对当前国际上争论纷纷的有关石珊瑚起源问题进行了形态学和分子系统学的比较研究,以期为更好地解决石珊瑚起源问题提供思路。     

Terrestrial mollusk evidence for the origin and sedimentary environment of the Late Tertiary Red Clay Formation in the Loess Plateau, China

The origin and sedimentary environment of theLate Tertiary (Neogene) Red Clay Formation in northernChina had long been controversial. A new mollusk recordfrom the Xifeng red clay (red-earth) sequence in the centralLoess Plateau provides the biological evidence for addressingquestions of its origin and environmental implication. Thestudy of composition and preservation condition of seventymollusk fossil assemblages reveals the initial ecological con-dition of the red clay formation, avoiding the effect ofpost-deposited alteration. The result shows that all of identi-fiable mollusk species are composed of terrestrial taxa, mostof them are the common species found in the overlying Qua-ternary Ioess-paleosol sequence. Most of fossil individualspreserved in the red clay strata are in living conditions basedon the investigation of fieldwork, indicating the originalpopulation. Thus, the mollusk fossil assemblages can be usedas an indicator of primary environment of the red clay for-mation. The mollusk record from the Xifeng red clay se-quence supports the view that the red clay is an aeolian ori-gin, similar to the overlying Quaternary loess deposits. Ourdata also reveal the history of environmental changes atXifeng from 6.2--2.4 Ma, which is coupled in phase with theformation and development of the Arctic ice sheets and theprocess of the Tibetan Plateau uplift. Both may be the majorcause and forcing mechanisms of the late Tertiaryenvironmental changes in the Loess Plateau.     

The reconstruction of fossil planation surface in China

On the basis of results of relative subjects, the fossil planation surface has been discussed by the authors from the point of geomorphologic view. The discussion contents included the characteristic information, research methods, paleotopography (gradient and altitude) and other problems about fossil planation surface. The recognition and reconstruction of fossil planation surface mainly rely on the following characteristic information: ( i ) the character of erosion unconformity surface; (ii) the paleo-weathering crust and residual deposits; (iii) the paleo-karst and filled deposit in the paleo-karst under the unconformity surface,and (iv) the character and environment of sediment above the unconformity surface. According to the above-mentioned characteristic information, the authors recognized and reconstructed two stages of fossil planation surface on Paleo-land of North China and Yangtze Paleo-land. These two fossil planation surfaces formed from Middle Ordovician to Lower Carboniferous and from Lower Permian to Upper Permian respectively. The paleo-gradient of fossil planation surface changed within 0.31‰-1.32‰, mostly less than 1.0‰. According to the developing depth of paleo-karst, the authors considered that in Suqiao buried-hill region of Paleo-land of North China, the paleo-altitude is 300 m or so above paleo-sea-level. The authors hope that the research is in favor of discussion about rising scale and process of the Tibetan Plateau. Besides, the research of fossil planation surface can provide a theoretical base for relative research,such as the reconstruction of paleoenvironment, the evolution and drift of paleo-continent, the formation and distribution of weathering ore deposits, the reservior and prospection of oil and gas, etc.     

A new species of great ape from the late Miocene epoch in Ethiopia

With the discovery of Ardipithecus, Orrorin and Sahelanthropus, our knowledge of hominid evolution before the emergence of Pliocene species of Australopithecus has significantly increased, extending the hominid fossil record back to at least 6 million years (Myr) ago. However, because of the dearth of fossil hominoid remains in sub-Saharan Africa spanning the period 12-7 Myr ago, nothing is known of the actual timing and mode of divergence of the African ape and hominid lineages. Most genomic-based studies suggest a late divergence date-5-6 Myr ago and 6-8 Myr ago for the human-chimp and human-gorilla splits, respectively-and some palaeontological and molecular analyses hypothesize a Eurasian origin of the African ape and hominid clade. We report here the discovery and recognition of a new species of great ape, Chororapithecus abyssinicus, from the 10-10.5-Myr-old deposits of the Chorora Formation at the southern margin of the Afar rift. To the best of our knowledge, these are the first fossils of a large-bodied Miocene ape from the African continent north of Kenya. They exhibit a gorilla-sized dentition that combines distinct shearing crests with thick enamel on its 'functional' side cusps. Visualization of the enamel-dentine junction by micro-computed tomography reveals shearing crest features that partly resemble the modern gorilla condition. These features represent genetically based structural modifications probably associated with an initial adaptation to a comparatively fibrous diet. The relatively flat cuspal enamel-dentine junction and thick enamel, however, suggest a concurrent adaptation to hard and/or abrasive food items. The combined evidence suggests that Chororapithecus may be a basal member of the gorilla clade, and that the latter exhibited some amount of adaptive and phyletic diversity at around 10-11 Myr ago.     

New frog family from India reveals an ancient biogeographical link with the Seychelles

About 96% of the more than 4,800 living anuran species belong to the Neobatrachia or advanced frogs. Because of the extremely poor representation of these animals in the Mesozoic fossil record, hypotheses on their early evolution have to rely largely on extant taxa. Here we report the discovery of a burrowing frog from India that is noticeably distinct from known taxa in all anuran families. Phylogenetic analyses of 2.8 kilobases of mitochondrial and nuclear DNA unambiguously designate this frog as the sister taxon of Sooglossidae, a family exclusively occurring on two granitic islands of the Seychelles archipelago. Furthermore, molecular clock analyses uncover the branch leading to both taxa as an ancient split in the crown-group Neobatrachia. Our discovery discloses a lineage that may have been more diverse on Indo-Madagascar in the Cretaceous period, but now only comprises four species on the Seychelles and a sole survivor in India. Because of its very distinct morphology and an inferred origin that is earlier than several neobatrachian families, we recognize this frog as a new family.     

无尾两栖类宿主与多盘科吸虫关系的初步探讨

文章调查研究了云南14种无尾两栖类体内寄生多盘吸虫的自然感染情况。滇中、滇东地区滇蛙和昭觉林蛙、滇南杜氏泛树蛙为多盘吸虫宿主。分析影响多盘吸虫宿主分布的原因可能有:地质构造、无尾两栖类宿主对多盘吸虫的免疫力和多盘吸虫侵入宿主产生的致病力对抗的不同。两栖类宿主和多盘吸虫的协同进化,导致同一种无尾两栖类宿主体内寄生的多盘吸虫有交叉感染情况存在。     

Affinities of 'hyopsodontids' to elephant shrews and a Holarctic origin of Afrotheria

Macroscelideans (elephant shrews or sengis) are small-bodied (25-540 g), cursorial (running) and saltatorial (jumping), insectivorous and omnivorous placental mammals represented by at least 15 extant African species classified in four genera. Macroscelidea is one of several morphologically diverse but predominantly African placental orders classified in the superorder Afrotheria by molecular phylogeneticists. The distribution of modern afrotheres, in combination with a basal position for Afrotheria within Placentalia and molecular divergence-time estimates, has been used to link placental diversification with the mid-Cretaceous separation of South America and Africa. Morphological phylogenetic analyses do not support Afrotheria and the fossil record favours a northern origin of Placentalia. Here we describe fossil postcrania that provide evidence for a close relationship between North American Palaeocene-Eocene apheliscine 'hyopsodontid' 'condylarths' (early ungulates or hoofed mammals) and extant Macroscelidea. Apheliscine postcranial morphology is consistent with a relationship to other ungulate-like afrotheres (Hyracoidea, Proboscidea) but does not provide support for a monophyletic Afrotheria. As the oldest record of an afrothere clade, identification of macroscelidean relatives in the North American Palaeocene argues against an African origin for Afrotheria, weakening support for linking placental diversification to the break-up of Gondwana.     

Earliest known crown-group salamanders

Salamanders are a model system for studying the rates and patterns of the evolution of new anatomical structures. Recent discoveries of abundant Late Jurassic and Early Cretaceous salamanders are helping to address these issues. Here we report the discovery of well-preserved Middle Jurassic salamanders from China, which constitutes the earliest known record of crown-group urodeles (living salamanders and their closest relatives). The new specimens are from the volcanic deposits of the Jiulongshan Formation (Bathonian), Inner Mongolia, China, and represent basal members of the Cryptobranchidae, a family that includes the endangered Asian giant salamander (Andrias) and the North American hellbender (Cryptobranchus). These fossils document a Mesozoic record of the Cryptobranchidae, predating the previous record of the group by some 100 million years. This discovery provides evidence to support the hypothesis that the divergence of the Cryptobranchidae from the Hynobiidae had taken place in Asia before the Middle Jurassic period.     

Two Jurassic salamanders with stomach contents from Inner Mongolia,China

Conchostracans and corixids are part of the diet of extant salamanders,an ecologically important fact in a lacustrine environment. Here we report their discovery in the guts of the aquatic Jurassic salamanders Jeholotriton paradoxus and Chunerpeton tianyiensis, formerly abundant at Daohugou,Ningcheng County,Inner Mongolia,China.This reveals something of the ecology of this im- portant,ancient,vertebrate and invertebrate assemblage.The new fossil evidence indicates the highly selective feeding of these Jurassic salamanders;Jeholotriton preyed only on juveniles of the conchostracan Euestheria luanpingensis,and Chunerpeton only on the corixid Yanliaocorixa chinensis.We can infer the dietary differences as a consequence of different jaw and hyoid structures; and thus niche partitioning in Jurassic salamanders.     

山东淄博煤田晚石炭世——早二叠世植物群落特征

山东淄博煤田晚石炭世—早二叠世植物化石经鉴定,共计37属104种,其中包括11个新种。分析了本区植物化石的埋藏类型,根据各类植物的生活习性和生境,将晚石炭世—早二叠世植物群划分为五个植物群落,讨论了它们的多度、成分、结构和生活型等特征,并采用信息函数数理统计方法,应用电子计算机对各植物群落的分异度和均衡度进行了计算。