A new species of Cristaria Schumacher, 1817 (Bivalvia, Unionidae) from Sichuan, China

The species diversity of freshwater mussels in the upper Yangtze River has been seriously underestimated, and human-induced disturbances have severely threatened the survival of local bivalve species. In this study, we describe a new freshwater mussel species, Cristaria wangyucheni Z. - G. Chen & Y. - T. Dai, sp. nov., from the Jialing River Basin in the upper Yangtze River, Sichuan, China, based on comparative morphology and molecular phylogeny.

Phylogenetic analyses of COI and 28 S rRNA gene fragments revealed that C. wangyucheni sp. nov. is a sister to the other species of Cristaria. The pairwise uncorrected COI p - distance analysis demonstrated genetic distances ranging from 10.10 % (between this species and C. truncata) to 13.17 % (between this species and C. “ beirensis ”). Morphologically, C. wangyucheni sp. nov. can be distinguished from its congeners by its medium-sized shell, which ranges from an elongated triangle to an irregular rectangle.

This discovery broadens our understanding of interspecific shell morphological variation within the genus Cristaria.