Abstract
In November 2007, an adult female (29.0 mm SL) Smilosicyopus leprurus (Sakai & Nakamura, 1979) was collected on Ani-jima Island, Ogasawara Islands, Tokyo Metropolis, Japan. Characterized by a row of canine-like symphyseal teeth on both the upper and lower jaws, ca. 17 upper jaw teeth and 0 transverse scale rows, short clearly-defined moustache-like coloring above the upper lip, and the body mainly greyish without a lateral band, the specimen represented the first record from the Ogasawara Islands. Previously, S. leprurus has been recorded from a wide distribution in the western Pacific, including the Ryukyu Archipelago and Mikura-jima Island, Izu Islands, Japan. A juvenile (13.7 mm SL) of S. leprurus collected from Mikura-jima Island in July 2010, and briefly reported in the “Red Data Book Tokyo 2014: Islands version” (Senou, 2014), is described in detail herein. Given the amphidromous life cycle of S. leprurus, the collection of the above two specimens suggests that the species presence on the Izu and Ogasawara islands was likely due to larval dispersal via the Kuroshio Current and/or other ocean currents such as the Kuroshio Counter-Current or North Equatorial Current from the Kuroshio basin, as the species is not considered as established on either island group. However, the adult specimen from Ani-jima Island, which had apparently inhabited the island for some time after its recruitment, suggests that S. leprurus could become established on the Ogasawara Islands in the future.
https://ror.org/05dqf9946 
