眼状紋を備える種ではR. texana, R. cervigoni, R. ackleyiなどが知られているが,斑紋の形状で区別できる(図)。 (上野・三宅)
Distinctive characters
(Family): Two dorsal fins. Caudal fin developed usually. Inner margin of pelvic separated from tail. (Genus): Forward extension of anterior rays of pectoral fin not reaching as far as tip of snout. Rostral cartilage robust, extending to tip of snout. (Species): Small thorns on dorsal surface of snout, outer margin of disc, and median line of back. Lower surface smooth except snout. 12〜13 orbital spines. Anterior 9 thorns of median row larger. Three rows of thorns on tail; median row with 32 thorns, left row 42, right row 45. Interspace between first and second dorsal fins equal to 2/3 of first dorsal base, and 4 thorns present on the space. A pair of ocellar spots on upper surface (Fig.).
Distribution:
Reported from off Rio de Janeiro, Brazil. Off Suriname.
Remarks:
The present species is similar to R. texana, R. cervigoni, and R. ackleyi in having a pair of ocellar spots, but discernible by their shape. (Uyeno and Miyake)