Pasiphaea gelasinus n.sp. belongs to a group of Pasiphaea species characterized by a distally notched telson and a mid-dorsal carina on carapace and some or all abdominal segments. Within this group it is distinguished by the rostral profile with anterior margin nearly vertical with a distinctive convexity, and by the presence of a distinct hollow laterally on the carapace on each side of the rostral base. The merus/ischium/basis spine formula for the first pereopod is 1-3/0/0 and for the second pereopod 7-12/0/0.
Pasiphaea gelasinus, new species, Pasiphaeidae, Caridea, Decapoda, Crustacea, South Indian Ocean.