The Smithian–Spathian boundary (SSB) crisis played a prominent role in resetting the evolution and diversity of the nekton (ammonoids and conodonts) during the Early Triassic recovery. The late Smithian nektonic crisis culminated at the SSB, ca. 2.7 Myr after the Permian–Triassic boundary mass extinction. An accurate and high-resolution biochronological frame is needed for establishing patterns of extinction and re-diversification of this crisis. Here, we propose a new biochronological frame for conodonts that is based on the Unitary Associations Method (UAM). In this new time frame, the SSB can thus be placed between the climax of the extinction and the onset of the re-diversification. Based on the study of new and rich conodont collections obtained from five sections (of which four are newly described here) in the Nanpanjiang Basin, South China, we have performed a thorough taxonomical revision and described one new genus and 21 new species. Additionally, we have critically reassessed the published conodont data from 16 other sections from South China, and we have used this new, standardized dataset to construct the most accurate, highly resolved, and laterally reproducible biozonation of the Smithian to early Spathian interval for South China. The resulting 11 Unitary Association Zones (UAZ) are intercalibrated with lithological and chemostratigraphical (δ ¹³ C _carb ) markers, as well as with ammonoid zones, thus providing a firm basis for an evolutionary meaningful and laterally consistent definition of the SSB. Our UAZ _8, which is characterized by the occurrence of Icriospathodus ex gr. crassatus , Triassospathodus symmetricus and Novispathodus brevissimus , is marked by a new evolutionary radiation of both conodonts and ammonoids and is within a positive peak in the carbon isotope record. Consequently, we propose to place the SSB within the separation interval intercalated between UAZ ₇ and UAZ ₈ thus leaving some flexibility for future refinement and updating. ZooBank LSID: urn:lsid:zoobank.org:pub:12326FE6-79DD-43A8-9421-26C3883FBE2E

A new specimen of Lariosaurus xingyiensis is described and provides new information on the dermal palate of the skull and the postcranial skeleton. Based on a comprehensive comparison with the holotype specimen, an amended diagnosis of L. xingyiensis is given on the basis of the following features: a medium-sized species of Lariosaurus with jugal absent, longitudinal diameter of upper temporal fenestra about 1.7 times longitudinal diameter of orbit, retroarticular process elongate, clavicles without anterolaterally expanded corners, posterior scapular process (blade) slender and elongate, humerus distinctly shorter than femur, and dorsal process of ilium with distinct tubercular ornamentation. Two phylogenetic analyses of Nothosauridae demonstrate that Nothosaurus as previously conceived is not monophyletic whereas Lariosaurus is a monophylum. Three species previously referred to Nothosaurus are more closely related to Lariosaurus and are hereby reassigned to Lariosaurus, namely, L. juvenilis, L. youngi, and L. winkelhorsti. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Lin, W.-B., D.-Y. Jiang, O. Rieppel, R. Motani, C. Ji, A. Tintori, Z.-Y. Sun, and M. Zhou. 2017. A new specimen of Lariosaurus xingyiensis (Reptilia, Sauropterygia) from the Ladinian (Middle Triassic) Zhuganpo Member, Falang Formation, Guizhou, China. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1278703.

Chaohusaurus is one of the earliest-branching ichthyosauriforms, but its cranial anatomy remains poorly known due to the lack of well-preserved material. Here, three nearly complete and well-preserved skulls of C. chaoxianensis are described, revealing new information on the cranial anatomy of the species. The prefrontal-postfrontal contact is clearly present in C. chaoxianensis, unlike in Cartorhynchus and basal Hupehsuchia. The squamosal and postorbital participate in the margin of the upper temporal fenestra as in most basal ichthyosauriforms. The postorbital region is narrow, with a deep ventral embayment representing an incomplete lower temporal fenestra. Three-dimensional preservation revealed that the posterior cheek region curves and faces almost posteriorly, whereas the orbit is directed slightly dorsally rather than strictly laterally. The cranial morphology of Chaohusaurus confirms the suggestion that the elongation of the nasal and posterior relocation of the external naris preceded snout elongation in ichthyosauriforms.

Here we report and describe a new assemblage of Thylacocephala (Crustacea) from the late Spathian (Early Triassic) of Chaohu, Anhui Province, South China. The assemblage consists of at least three species from different genera: the small-sized Microcaris rectilineatus n. sp. appears the most abundant, while the large-sized Ankitokazocaris sp. and Diplacanthocaris chaohuensis n. gen. n. sp. are rare. A morphometric analysis of the carapace outline separates Diplacanthocaris chaohuensis n. gen. n. sp. from other genera. Along with Ankitokazocaris chaohuensis Ji et al., 2017 and Kitakamicaris sp. from the horizon 28 m above this assemblage, four different genera of Thylacocephala occur in the Chaohu Fauna. With additional materials reported from Japan and North America, the Early Triassic is now known as the period when Thylacocephala reached their highest diversity and widest geographical distribution. Thylacocephala quickly diversified shortly after the Permian–Triassic mass extinction, probably because of their ability to survive in a relatively low-oxygen environment. Thylacocephalan fossils from Chaohu are found in dense concentrations, suggesting they might have constituted a food source for the fishes and marine reptiles in the Chaohu Fauna.UUID: http://zoobank.org/b24e82a7-ea9a-49dc-9c6c-8ad8262db276

SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Li, Z.-G., D.-Y. Jiang, O. Rieppel, R. Motani, A. Tintori, Z.-Y. Sun, and C. Ji. 2016. A new species of Xinpusaurus (Reptilia, Thalattosauria) from the Ladinian (Middle Triassic) of Xingyi, Guizhou, southwestern China. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1218340.