An almost complete Nothosaurus specimen is described in particular from the Upper Member of the Guanling Formation (Pelsonian, middle Anisian, Middle Triassic) of the Xinmin District, Panxian County, Guizhou Province, Southwestern China. The specimen provides new information on the postcranial osteology of the species. The diagnosed features of the species are revised by the following characters: four premaxillary fangs followed by one small conical premaxillary tooth and five to six small maxillary conical teeth followed by paired maxillary fangs, no posterior process in the interclavicle, four carpals, four sacral vertebrae and hyperphalangy in both manus and pes. In some aspects of its postcranial morphology, GMPKU-P-3014 appears to approach Lariosaurus more closely than Nothosaurus, such as no posterior process in the interclavicle, four carpals, four sacral vertebrae and hyperphalangy in both manus and pes, which provides the important characters to reevaluate the phylogenetic relationships of Nothosaurus and Lariosaurus within the Sauropterygia. GMPKU-P-3014, GMPKU-P-1080 and IVPP V 14294 are different from all other nominal species of Nothosaurus by their size, dentition and the skull future pattern. In addition they have the most similar shape and important proportions of the skull, as well as the same location and stratigraphic level. Thus, they are the same species and indicates that N. rostellatus is a junior synonym of N. yangjuanensis and should be abandoned.

The conodonts biostratigraphy from the Upper Member of the Guanling Formation to the basal Yangliujing Formation in Yangjuan-Chupiwa Section was re-analysed and the conodont Neogondolella constricta cornuta, Neogondolella constricta longa, Neogondolella constricta balkanica, Neogondolella alpina alpina, Neogondolella cf. Neogondolella acuta, Paragondolella excelsa, Paragondolella torna?sis were described. Based on the stratigraphical distribution and morphological variations of these conodonts, five conodont zones were re-established and the relevant biostratigraphic comparisons were made. The results reveal that: 1) From the Upper Member of the Guanling Formation to the basal Yangliujing Formation, five conodont zones can be investigated. In ascending stratigraphical order, they are Nicoraella germanica Zone (the bottom undefined), Nicoraella kockeli Zone, Neogondolella bifurcata Zone, Neogondolella constricta Zone, and Neogondolella constricta cornuta Zone (the top undefined); 2) These conodont zones are comparable to the same-named conodont zones of the Upper Longtou Formation at Qingyan Section (platform-margin slope) and of the Guandao wedge at Guandao (2) Section (basin-margin facies) in Guizhou Province, and these conodonts are also present in the ammonoid binodosus Zone, trinodosus Zone, and reitizi Zone in the West Tethys; 3) It further proves that the studied strata can be considered as the Pelsonian-Illyrian substages of the Anisian stage (Middle Triassic), not going into the Ladinian of the Middle Triassic.

On the basis of detailed morphological description and anatomy comparison of two specimens of Keichousaurus hui, the diagnostic characters of Keichousaurus hui have been reconfirmed: small upper temporal fenestra, large orbits, thickened proximal end of ribs and extremely broad ulnae; and more morphological information of Keichousaurus hui is added. The sexual dimorphism of three adults and the ontogenetic stage of a juvenile have been identified through the measurement of different bones. Furthermore, from the paleogeographic information and observation of the embryos, it’s inferred that the reproduction mode is most likely viviparous, but the possibility of ovoviviparity cannot be totally ruled out.

The present study is based on ammonoids collected from the strata above the ammonoid Trachyceras multituberculatum zone of Wayao Member of “Falang Formation” (Late Triassic) at the Niubudai Section in Luoping County, Eastern Yunnan Province. Eight species of four genera, including one conform species and three indeterminate species were recognized, among which Trachyceras aonoides, Simonyceras simonyi are firstly found in China. According to their assemblage and stratigraphic distribution, two ammonoid zones were recognized in ascending order: Trachyceras aonoides Zone, Austrotrachyceras triadicum Zone, corresponding to the middle-late Early Carnian of Late Triassic in age.

Here the true tailbends are reported in two complete skeletons of Guanlingsaurus from the late triassic of Guizhou Province, southwestern China after accurate observations, measurements and comparisons with Ichthyosaur of early jurassic. They have acquired the wedge-shaped centra and the angles in these tailbends are around 15°while those in jurassic types are around 60°. This study shows for the first time that wedge-shaped tailbend centra already existed in merriamosaurs as early as late triassic time, probably being a result of coevolution between ichthyosaurs and the environment. The occurrence of the true tailbend connected triassic and jurassic ichthyosaurs that used to be considered as separate groups in previous literature. The present finding also suggests the monophyly of ichthyopterygia.

Combining mathematical analysis with the approach of chemo-biostratigraphy, the authors concentrated on numerical simulation of chemical cycle in the Upper-Mid Devonian sections at Baqi, Gubi and Dujin, Guangxi. The results are as follows: The relevant elemental combinations reflecting certain regional environmental changes are steady and clear; numerical analysis at these stratum sections shows the steady and clear chemical cycles, with which more refined subdivision in a conodont phylogenetic biostratigraphic zonation and cycle to cycle comparison between different sections can be made. Therefore it improves the resolution and precision of subdivision and correlation.

The REE component variation rules indicate that the Yangjian section, where Panxian Fauna was found, was in a weakly reductive depositional environment in most of its aggradational time. The unconventional changes of the contents of REE in the samples were mainly influenced by the volcanism at that time; and there are two types and four subtypes of sedimentary provenance, which are from tholeiite and terrestrial debris accordingly. The composing characteristics of LREE, MREE and HREE in the sediment samples are very similar, which turns out to be a stable evolvement feature, and thus indicates that the section was once in a steady tectonic environment.

Chemo-stratigraphic analysis will help to solve the problem of the Ordovician-Silurian Boundary, which might locate in the bed of mudstone intercalated with dolostone from the top part of the Lower Member to the basal part of the Middle Member of the Kepingtage formation at the Dawangou Section in the Keping County. Systematically collected seventy two samples were measured by ICP, and data were compared and emended. The w(Ce)/w(La) chemo-stratigraphic analysis indicates that this bed can be subdivided into three chemo-beds. The chemo-fluctuation might reflect the fluctuation of oxidation-deoxidation, and can be correlated with the changes of fossils. The chemo-spike might be corresponding with the anomaly around the boundary of the Ordovician-Silurian at the east Yangtze Gorger.

The Panxian Fauna is mainly characterized by well-preserved and articulated skeletons of Middle Triassic (Anisian) marine reptiles with high diversity, associated with abundant invertebrate fossils, such as bivalves, brachiopods as well as cephalopods, and some as yet undescribed taxa. Stratigraphically, it is occurred at the Upper Member of the Guanling Formation, ascribed to the conodont Nicoraella kockeli Zone, which indicates that the age of this fauna is Pelsonian (Middle Anisian). Therefore, the Panxian Fauna is older than the Grenzbitumenzone fauna at Besano/Monte San Giorgio area of Italy/Switzerland border (near Anisian/Ladinian boundary), and represents the oldest marine reptile fauna of the Middle Triassic throughout the world. Such a rich, diversified and perfectly preserved paleontological assemblage with the exact stratigraphic horizon and definitive age not only provides abundant materials for exploring the taxonomy, evolution, and origin of the marine reptiles, but also has great significance for developing the study of paleoecology and biogeographic provincialism. So far, five genus and five species, including the oldest mixosaurid ichthyosaurs, the oldest lariosaurs and the first true aquatic protorosaur(Dinocephalosaurus orientalis), have been reported from the Panxian Fauna. Most of them are adapted to epicontinental environment or shallow sea, and show a strong West Tethyan affinity. The strata bearing the Panxian fauna consists of four or five tuff beds and seven volcanicities were recognized, which might be caused the extinction of these marine reptile animals directly.

Petrological samples collected from the Upper Triassic Wayao Formation bearing t he Guanling Fauna,located in Xinpu area of Guanling County, Guizhou rovince, were observated under microscope. Three kinds of lithology can be distinguished on the basis of the bio-abundance. Considering the bio-assemblage of the Guanling Fauna, its taphonomic environment characteristics can be concluded as follows: the sea water was relatively deep, lower energy, peachful and anoxic condition with normal paleosalinity and warmer climate. In addition, the distributions of the conodontParagondolella and the bivalve Halobia confirm the taphonomic environment and indicate the occurrence of the anoxic event as well. The study of paleoredox markers and fossil diversity finds two main significant factors. One is the fine grain and compact texture of marly lime stone bearing the Guling Fauna, which makes the remains deposit nearly intact. The other is the layer of reptile and crinoid fossils coincide well with w(Ce)/w(La) value over 2.0 and increasing positively, which reveals a high anoxic condition just like a protecting cover which keep the remains out of the oxygen.

Samples collected from the Wayao Formation, which yields the Guanling Fauna, and the underling formation, the Zhuganpo Formation, were treated for conodont analysis. The study result shows that two conodont zones, Paragondolella polygnathiformis-P.tadpole Assemblage Zone and the P. polygnathiformis Zone can be recognized. Comparing with the international and domestic related information, a conclusion can be drawn that their epoch should belong to the Middle or Late Carnian of the Late Triassic. So the final result indicates that the age of the Guanling Fauna belong to the middle Carnian of the Late Triassic, maybe the late Carnian, not to the Ladinian of the Middle Triassic.

The Late Ordovician-Silurian-Devonian-Early Carboniferous stratigraphic division and correlation, including the chronologic correlation of the Donghe Sandstone, which are the old great difficult key stratigraphic problems interfering with the development of the oil and gas exploration in the Tarim Basin, are synthetic studied by systematically applying chemo-biostratigraphy. Several important relevant stratigraphic boundaries are recognized, and the Donghe Sandstone is attributed to the Frasnian, Late Devonian. The results of the study in particular proves that chemo-biostratigraphy has great significance and is a practical tool for high resolution stratigraphic division and correlation, especially for the region and/or the bed with rare fossils.

The changes of Mid-Holocene paleoclimate-paleoenvironment along the eastern coast of Zhejiang province and its influence on the Hemudu Ancients are discussed in this paper. Results of the study indicate that the coming of Mid-Holocene megathermal maximum is an important factor for the domicile and the development of the Hemudu Ancients, and it is an favorable condition for the development of Hemudu oryzo-agriculture at that time. The divided periods of the paleoclimatic-paleoenvironmental changes in Zhejiang Province can be well correlated with the periods of the development of the Hemudu Ancients. The tropical climatic-environmental changes, including the aggravation of natural calamities caused by these changes, have great influence on the changes of the life of the Hemudu Ancients. Especially the process of the paleoclimatic-paleoenvironmental changes from slow cooling turning to rapid warming is probably one of the essential causes for the great change of the life of the Hemudu Ancients.