Review of the Genus Pseudiberus Ancey, 1887 (Eupulmonata: Camaenidae) in Shandong Province, China

ABSTRACT The genus Pseudiberus Ancey, 1887, in Shandong, China, distributed in the mid to the south mountainous areas of the province, represents the largest terrestrial mollusks in this region. By molecular phylogenetic inference and genetic distance comparison based on ITS2 + 16S sequences, P. tectumsinense tectumsinense (Martens, 1873), P. tectumsinense zenonis (Gredler, 1882), P. tectumsinense anderssoni (Odhner, 1925) and P. tectumsinense depressus (Yen, 1935), are confirmed to be subspecies under P. tectumsinense (Martens, 1873). Pseudiberus tectumsinense pingi, new subspecies, is proposed to be new based on shell morphology, anatomy, and evidence of molecular phylogeny. Pseudiberus futtereri (Andreae, 1900) is removed from the species list of Shandongese Pseudiberus. The proximal accessory sac, observed in all the anatomically known Pseudiberus from Shandong, is described for the first time in dart sac apparatus from the bradybaenine snails. The variations and patterns of the proximal accessory sac among Pseudiberus tectumsinense subspecies and P. chentingensis distributed east to the Taihangshan Mountain Chain are examined. The close relationship among Shandong's Pseudiberus might be indicative of their rather recent evolutionary divergence, which was possibly driven by allopatric isolation of populations confined to refugial habitats like isolated mountain tops surrounded by extensive flood plains.