A small species, without humps on abdomen. Carapace depressed as usual, with three longitudinal ridges ornamented with scaly sculpture; three obtuse teeth on median ridge; each lateral ridge originates from small two teeth of supraorbital border, being interrupted medially and then widening posteriorly; two transverse linear furrows between submarginal furrow and posterior margin of carapace. Outer margin of antennal second segment divided into three lobes, and inner margin into smaller four or five; an oblique ridge from its antero-external sharp angle to basal inner part; distal margin of fourth segment divided into five lobes. Each abdominal segment provided with a transverse linear furrow branching for and aft; this root-like rugae medially interrupted.
Distribution:
West Atlantic from North Carolina through the Gulf of Mexico and the Caribbean Sea to Brazil, 15-180 m deep.
Remarks:
The close congener, S. americanus (Smith) ranging from North Carolina to the Gulf of Mexico, differs from this species in several important features of the carapace and abdomen.