Rostrum armed with 7 to 9 dorsal teeth; in females, sigmoid-shaped, toothless, on distal third to half, upcurved and exceeding antennular peduncle; in large males, curving downward, the unarmed portion absent and only reaching to middle of second antennular article; both shapes found in young males; epigastric tooth small, absent in large males; postrostral crest almost reaching to posterior margin of carapace, feebly grooved or flat; longitudinal suture generally reaching 3/4 of carapace length; antennular flagella 0.4 to 0.6 times the length of carapace.