Sixteen characteristics of 3 populations of Pelophylax plancyi in Henan Province were measured.The results of canonical discriminant and cluster analyses of the morphometric data-set indicated that populations of eastern Henan and Mt.Dabie should belong to P.plancyi and P.hubeiensis,respectively.The taxonomic placement of Mt.Funiu population is uncertain.
This study aims to characterize the geological properties and to evaluate the gas potential of the lower Paleozoic shales in the Yichang area by integrating a series of analyses on geology and geochemistry, well logging data, and 2D seismic interpretation. The thickness of the lower Cambrian Shuijingtuo shale is less than 10 m in the southeast but may exceed 120 m in the southwest area. The thickness of the upper Ordovician Wufeng shale and the lower Silurian Longmaxi shale (hereafter referred to as the Wufeng-Longmaxi shale) gradually increases in thickness from <10 m in the south to 40–50 m in the northeast. The organic matter of the above two sets of black shale is mainly dominated by type I and II1 kerogen. The thickness of black shale units with TOC > 2% is more than 10–20 m, commonly located at the bottom of the shale intervals. Black shales near the Huangling anticline have low thermal maturity due to its relatively shallow burial. The predominant minerals are quartz and clay minerals. Carbonate contents of the Shuijingtuo shale are relatively high compared to the Wufeng-Longmaxi shale. Pores are more developed in the Wufeng-Longmaxi shale than those in the Shuijingtuo shale. Natural fractures are common in the Shuijingtuo shale but are rare in the Wufeng-Longmaxi shale. The well logging and lab analytical results both indicate that the natural gas content in the black shales is relatively high. The prospective area of the Shuijingtuo interval for shale gas production is nearly 670 km2, located in the southwestern region. In contrast, the prospective area of the Wufeng-Longmaxi interval for shale gas production is approximately 1590 km2, situated in the eastern area.
A new specimen of an enigmatic hupehsuchian genus is reported. The genus was first recognized by Robert L. Carroll and Zhi-ming Dong in 1991, who refrained from naming it because of the poor quality of the only specimen known at the time. After more than two decades, we finally report a second specimen of this genus, which remained unprepared until recently. The new specimen preserves most of the skeleton except the skull, allowing us to erect a new genus and species, Eretmorhipis carrolldongi. The new species shares many characters with Parahupehsuchus longus, including the strange axial skeleton that forms a bony body tube. However, the body tube is short in the new species, being limited to the pectoral region. The vertebral count and limb morphology considerably differ between the new species and P. longus. The forelimb of E. carrolldongi is markedly larger than its hind limb as in Hupehsuchus nanchangensis but unlike in P. longus. The new species is unique among hupehsuchians in a list of features. It has manual and pedal digits that spread radially, forming manus and pes that are almost as wide as long. The third-layer elements of the dermal armor are unusually large, spanning four vertebral segments, yet there are substantial gaps among them. With the addition of the unique paddle, it is now clear that Hupehsuchia had diverse forelimb morphologies spanning from paddles to flippers, unlike ichthyopterygians that were taxonomically more diverse yet only had flippers.
The Upper Devonian Shetianqiao Formation mudstones are considered to be the most petroliferous shale gas source rocks in the Shaoyang Sag of Xiangzhong Depression in China. These Shetianqiao dark mudstones have been collected systematically to investigate their geochemical characteristics by analysing their major elements, trace elements, and rare earth elements (REEs), in order to reveal their provenance, palaeoenvironment and tectonic setting. The results show that the total REEs content (ΣREE) of dark mudstone is 34.22–246.62 ppm (average 131.66 ppm) and characterized by low ΣREE, light rare earth element (LREE) enrichments, negative Eu anomalies, and minor negative Ce anomalies. The normalized distribution pattern of REE, Eu anomaly, as well as discrimination diagrams of trace elements and REEs, are applied to explain the source rock types and properties of Shetianqiao mudstones. The results indicate that the sediments have a weak sedimentary recycling and mainly originated from the upper continental crust, and the source rocks of the black mudstones are mainly constituted by felsic granite. The Ce anomaly, Th/U, V/Sc, V/Cr, and V/(Ni + V) ratios of the dark mudstones suggest a long‐term oxidizing depositional environment interrupted by a short period of a dysoxic/anoxic depositional environment in the middle section of the formation. This short period corresponds to a dramatic marine transgression with relatively high TOC. The La/Ce, La N /Sm N , Ce anomaly, and normalized REE distribution pattern characteristics indicate that the depositional process of the Shetianqiao mudstones has consistently been influenced by the regional upwelling hydrothermal activities. The chemical index of alteration (CIA) and Al 2 O 3 ‐(CaO* + Na 2 O)‐K 2 O triangular plot reveal that a warm and humid climate with moderate chemical weathering in the source areas of the Shetianqiao mudstones occurred during the deposition. The ratio of major elements, trace elements, and REEs are used to analyse the tectonic setting of the depositional area which suggests that the source area is dominated by continental island arc tectonic setting. Combined with the previous regional studies, it is concluded that the continental island arc granite formed by plate collisions in the Caledonian stage constitutes the main source of the Shaoyang Sag during the Shetianqiao period. The depositional environment was not stable due to the lasting influence of deep hydrothermal activities. The upwelling currents controlled by hydrothermal activity transport nutrients to the study area, resulting in the formation of organic‐rich mudstones.
Abstract Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including the enigmatic Hupehsuchus that possessed an unusually slender mandible. A new specimen of this genus reveals a well-preserved palate and mandible, which suggest that it was a rare lunge feeder as also occurs in rorqual whales and pelicans. The diversity of feeding strategies among Triassic marine tetrapods reached their peak in the Early Triassic, soon after their first appearance in the fossil record. The diet of these early marine tetrapods most likely included soft-bodied animals that are not preserved as fossils. Early marine tetrapods most likely introduced a new trophic mechanism to redistribute nutrients to the top 10 m of the sea, where the primary productivity is highest. Therefore, a simple recovery to a Permian-like trophic structure does not explain the biotic changes seen after the Early Triassic.
Abstact: It is suggested that the characters of Traumatocrinus hsui Mu infants change remarkably in different ages; however, the characters of adult individuals are comparatively stable. The present study examined specimens of infant and adult individuals of T. hsui . Based on these observations, the authors divided the ontogeny of T. hsui into four infant stages (infant stage I‐IV) and one adult stage. In addition, the characters of the anal pyramid are supplemented and the infrabasal plates of T. hsui are confirmed in the present paper for the first time.
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