Taxonomy and distribution of three species of Barleeia (Mollusca, Gastropoda, Littorinimorpha, Barleeiidae) in the intertidal zone off the coast of China, with description of a new species, Barleeia qilu Han, Qi & Kong, n. sp.

Barleeiids are common marine microgastropods worldwide. Three species of Barleeia (Barleeia annamitica, Barleeia qilu n. sp. and Barleeia dunedini) found in the intertidal zone off the coast of China are described in this study. Morphological comparisons and species delimitation analyses using the universal mitochondrial COI gene sequence showed the distinctiveness of three species. Barleeia qilu n. sp., differentiated by its pointed apex and sutural channelling, was identified as a new species following morphological observation and phylogenetic analysis. Barleeia dunedini, previously considered as Ansola angustata (Pilsbry, 1901), has emerged as a distinct species and is probably the most widely distributed barleeiid in China. Barleeia annamitica, which has a broader distribution than previously recorded, is reported in China for the first time. Additionally, we propose to reassign Ansola angustata to the genus Barleeia based on the phylogram. Morphological illustrations, diagnoses, descriptions, and their approximate distribution along the coast of China are provided for each species. This study improves our understanding of the species composition, distribution and diversity of Barleeia in the intertidal zone of China.