This species is distinguished from all its congeners by the following: with a long snout, head length from the tip of the snout to the front of the eye) is 35-38% HL (vs. 24-32 %HL); eyes near the dorsal margin of the head (vs. eyes located on lateral margin of head in all species except S. duccis); maxilla with an enlarged anterior process greater than one-third the length of the descending blade (vs. reduced anterior process and less than one-third the length of descending maxillary blade); a robust oral dentition usually visible externally in mature specimens (vs. obscured dentition in all species except duccis, rex) (Ref. 126780).