Synalpheus superus Abele & Kim, 1989

Synalpheus superus Abele & Kim, 1989: 18, figs. 9, 10.

Material examined: Panamá: Miraflores Locks, Panama Canal, 1 male, holotype (USNM 237649); 21 males and 16 females, paratypes (USNM 237643); 21 males, 9 females, 3 juveniles (USNM 237705), 1 ovig. female (USNM 237708), 17 Jan. 1972. Mexico: Acapulco, Guerrero, 5 males, 3 females (2 ovig.) (USNM 99814a), 8 Jun. 1955.

Type Locality: Miraflores Locks, Panama Canal, Panama.

Habitat: Dredged from sediments around the Miraflores Locks, Panama Canal (Abele & Kim 1989), with no further information in the original publication.

Distribution: Eastern Pacific: vicinity of Panama Canal (Abele & Kim 1989); Acapulco, Guerrero, Mexico (this study).

Remarks: The distribution of S. superus is herewith considerably extended northwards, from central Panama to Guerrero, Mexico. Synalpheus superus is a species with significant morphological intraspecific variation, with no apparent influence of sex or size. This variation mainly affects the proportions of the articles of the cephalotoracic appendages and is most obvious in the second and third pair of pereiopods. Also observed were differences in the length of the rostrum, which can be shorter or longer than the ocular spines. Another important variation is the length of the scaphocerite. In the original description, Abele & Kim (1989) stated that the scaphocerite blade reaches the distal end of the carpocerite; however in their figure (Abele & Kim 1989, Fig. 9), it appears to be shorter than the antennular peduncle and the carpocerite. We re-examined this feature in the USNM material and found that the left scaphocerite of the holotype overreaches slightly the middle of the third segment of the peduncle, while in the right side it reaches up to the distal end of this segment.