Rhynchobatus mononoke, a new species of wedgefish (Rhinopristiformes: Rhinidae) from Japan, with comments on Rhynchobatus laevis (Bloch and Schneider 1801)

Abstract

Rhynchobatus mononoke sp. nov. (Rhinopristiformes: Rhinidae) is described from mature male and female specimens from southern Japan. A juvenile specimen, newly born from a captive individual collected from Kagoshima, is also referenced (non-type). The new species can be distinguished from congeners by a combination of its obtusely wedge-shaped snout, bluntly rounded dorsal fins, first dorsal fin originating about level with the pelvic-fin origin, and the outer fold on the spiracle posterior margin more pronounced than the inner fold. Distinctive coloration of the new species included a black blotch, followed by a single white spot (rarely absent) posterodorsally on the middle of the pectoral disc, and a large black blotch covering the anterior half of the undersurface of snout. Distinct white spots distally on the pectoral disc to the middorsal area were absent. Most previous records of species of Rhynchobatus in Japanese waters were reidentified as Rhynchobatus australiae, except for the records from the northern East China Sea. Rhynchobatus mononoke appears to be endemic to southern Japan.