A new species of Nanhsiungchelys (Testudines: Cryptodira: Nanhsiungchelyidae) from the Upper Cretaceous of Nanxiong Basin, China.

Nanhsiungchelyidae are a group of large turtles that lived in Asia and North America during the Cretaceous. Here we report a new species of nanhsiungchelyid, Nanhsiungchelys yangi sp. nov., from the Upper Cretaceous of Nanxiong Basin, China. The specimen consists of a well-preserved skull and lower jaw, as well as the anterior parts of the carapace and plastron. The diagnostic features of Nanhsiungchelys include a large entire carapace length (∼55.5 cm), a network of sculptures consisting of pits and ridges on the surface of the skull and shell, shallow cheek emargination and temporal emargination, deep nuchal emargination, and a pair of anterolateral processes on the carapace. However, Nanhsiungchelys yangi differs from the other species of Nanhsiungchelys mainly in having a triangular-shaped snout (in dorsal view) and wide anterolateral processes on the carapace. Additionally, some other characteristics (e.g., the premaxilla is higher than wide, the maxilla is unseen in dorsal views, a small portion of the maxilla extends posterior and ventral of the orbit, and the parietal is bigger than the frontal) are strong evidence to distinguish Nanhsiungchelys yangi from Nanhsiungchelys wuchingensis. A phylogenetic analysis of nanhsiungchelyids places Nanhsiungchelys yangi and Nanhsiungchelys wuchingensis as sister taxa. Nanhsiungchelys yangi and some other nanhsiungchelyids bear distinct anterolateral processes on the carapace, which have not been reported in any extant turtles and may have played a role in protecting the head. The Nanxiong Basin was extremely hot during the Late Cretaceous, and so we suggest that nanhsiungchelyids might have immersed themselves in mud or water to avoid the heat, similar to some extant tortoises. If they were capable of swimming, our computer simulations of fluid flow suggest the anterolateral processes could have reduced drag during locomotion.

[Mineralogical and spectral characteristics of "Gaozhou stone" from Jiangxi Province].

The seal stone is a kind of artwork with historical and cultural characteristics of China, which has been playing an important role in Chinese traditional culture. "Gaozhou stone", a new kind of the seal stone, has been found in the market recently. To investigate the mineralogical and spectral characterastics of "Gaozhou stone", samples were studied by using XRF, XRD, FTIR, SEM and DTA. Measurements by XRD reveal that kaolin minerals (kaolinite, dickite), pyrophyllite and minor sericite and illite occur in the ores. When kaolinite and dickite are associated, it is not easy to differentiate them from each other. Although some reflections overlap others, kaolin polytypes can be differentiated by XRD patterns in the range 18°-40° (2θ), the reflections at 0. 395, 0. 379, 0. 343, 0. 326, 0. 294, 0. 280, 0. 232 and 0. 221 nm are diagnostic of dickite. The XRD results indicate the presence of transitional mineral of kaolinite and dickite in these samples. The main chemical components of "Gaozhou stone" are SiO2 and Al2O3 with minor Fe2O3, K2O and Na2O, corresponding with that of kaolin minerals. The OH groups in kaolin group minerals have attracted considerable attention as a sensitive indicator of structural disorder. In principle, dickite has three bands, whereas kaolinite has four bands at the OH-stretching region. According to the results of FTIR, transitional mineral of kaolinite and dickite in "Gaozhou stone" has 3 absorption bands of 3 670, 3 650 and 3 620 cm-1 in high frequency region. The intensity of 3 670 cm-1 band that belongs to outer layer hydroxyl vibration is approximately equal to the intensity of 3 620 cm band ascribing to inner layer OH vibration. This value will only have subtle changes due to the different component ratio of kaolinite and dickite layers. Micro-morphology viewed by SEM presents irregular platy or pseudo-hexagonal platy particles with an average diameter of 0. 5-4 µm of "Gaozhou stone". Such morphologies are quite similar to other seal stones of China that the formation environments of all these stones are of the same kind. DTA curves demonstrate that the disparity of dehydroxylation temperature can be seen as a differential feature for identifying kaolin group minerals, but that is not undoubted. And what's more, the size of the mineral grains seems has a greater effect on the disparity of dehydroxylation temperature. This research shows that the mineral type of "Gaozhou stone" is similar to "Four Famous stones of China", and it could be a viable substitute of other famous seal stones. In this point, "Gaozhou stone" has a broad market prospect.