Carapace strongly compressed and not hard, upper half being markedly convex dorsally and flattened; gastro-orbital carina across median part of lateral surface, being continuous with lower lateral rostral carina and bifurcating just behind orbit; an infra-gastro-orbital carina below posterior half of gastro-orbital one; subhepatic, infra-subhepatic and submarginal carinae distinct, and a transverse post-hepatic carina between gastro-orbital and subhepatic carinae also distinct; upper lateral rostral carina just to bottom of orbit. Rostrum about half as long as carapace, tapering rapidly from anterior end of orbit, and curving gently upward; both borders with fine serrations throughout their lengths, and dorsal carina of carapace also with serrations without any interruption. Median dorsal carina of each abdominal segment strong, and in third to sixth segments each posterior end produced to be a strong spine.
Distribution:
West Atlantic from the Bermudas and the Gulf of Mexico through Grenada to Brazil, the East Atlantic from Senegal to Angola, the Indian Ocean and the South Pacific, 850-3,952 m deep.