Two new species of the genus Nassarius (Gastropoda: Nassariidae) from the South China Sea

Two species of Nassarius Dumeril, 1805 from the South China Sea are described and illustrated. The specimens are in the Nassariidae collection of the Marine Biological Museum of Chinese Academy of Sciences, Qingdao. Nassarius concavus sp. nov., from the sandy bottom at a depth of 180 m, resembles Nassarius glabrus Zhang and Zhang, 2014 in general shell morphology, but differs from the latter in having a smaller, more slender adult shell without axial ribs on the upper teleoconch whorls. Nassarius nanshaensis sp. nov., from the Nansha Islands at a depth of 56-147 m, is similar to Nassarius maxiutongi Zhang, Zhang and Li, 2019 in the shell sculpture, but differs in having a more slender shell with a higher spire, and fewer cusps on the rachidian tooth (9-11 vs. 13-17).