First record of a callionymid fish, Eleutherochir mccaddeni, from Japan

Abstract

Eleven specimens of Eleutherochir mccaddeni Fowler, 1941 (Perciformes; Callionymidae) were collected in the Ryukyu Islands, from the surf zones of sandy beaches on Iriomote and Okinawa Islands. The specimens were characterized by the following characters: first dorsal fin blackish with 4 spines; 10 to 11 (mostly 10) anal fin rays; lower jaw protruding anteriorly; 9 to 11 pairs of fleshy papillae on lower lip; small brown and white spots scattered on back. Eleutherochir mccaddeni is not a junior synonym of E. opercularis (Valenciennes). This occurrence represents the first record from Japan and the northernmost record for the species, E. mccaddeni generally being limited to sandy beaches (i.e., beach substrate not of coral reef origin). Such a habitat, however, is rare in the Ryukyu Islands, still existing examples being seriously threatened by recent reclamation.