A new species of the callichirid ghost shrimp genus Lepidophthalmus Holmes, 1904 (Decapoda: Axiidea) from the Ryukyu Islands, Japan

抄録

A new species of callichirid ghost shrimp belonging to the genus Lepidophthalmus Holmes, 1904, is described based on material from the Yaeyama Islands, southern Ryukyu Islands, Japan. Lepidophthalmus yaima sp. nov. resembles L. rosae (Nobili, 1904) closely, which was originally described based on a single female specimen from the Red Sea and has since been recorded widely in the Indo-West Pacific region. Recent genetic studies have shed light on cryptic speciation among geographically distant decapod populations, and consequently, morphological comparison is restricted to the holotype of L. rosae for the purpose to clarify the identity of the new species. The distinguishing features of the new species include a proximal spine on the lower margin of the minor cheliped merus and the nearly straight proximal outer margin of the uropodal exopod. Genetic analysis using the mitochondrial 16S rRNA gene, comparing a specimen from the Ryukyu Islands with two specimens from Bali, Indonesia, registered in GenBank as L. rosae, indicated that the Ryukyu specimen was genetically distinct from the latter, although the exact identity of the Bali specimens requires confirmation. Currently, the new species is known with certainty only from the Yaeyama Islands, burrowing in intertidal sediments of beaches and shorelines near estuaries.