A new pufferfish of the genus Torquigener that builds “mystery circles” on sandy bottoms in the Ryukyu Islands, Japan (Actinopterygii: Tetraodontiformes: Tetraodontidae)

Abstract

Torquigener albomaculosus sp. nov. is described based on two specimens collected from sandy bottoms at depths of 15 and 18 m along the south coast of Amami-oshima Island in the Ryukyu Islands. This new species is distinguished from all other species of Torquigener by the following unique combination of characters: dorsal-fin rays 9 (10); anal-fin rays 6; pectoral-fin rays 16 (dorsalmost ray nubbin-like and rudimentary); vertebrae 8 + 11 = 19; no solid, dark, longitudinal stripe nor longitudinal rows of dark spots on the mid-side of body from behind pectoral fin to caudal-fin base; no vertical markings on cheek; dorsal half of head and body covered with fine brown reticulations and many white spots; ventral half of head and body silvery white covered by many white spots from chin to above anal-fin origin; dorsal rim of eye light yellow; and many two-rooted spinules on head and body. Males of T. albomaculosus build unique circles as spawning nests, these being 2 m in diameter on sandy bottoms at depths from 10 to 30 m at Amami-oshima Island.