Crenicarpus, Drumm, David T. & Bird, Graham J., 2016

Drumm, David T. & Bird, Graham J., 2016, New deep-sea Paratanaoidea (Crustacea: Peracarida: Tanaidacea) from the northeastern Gulf of Mexico, Zootaxa 4154 (4), pp. 389-414 : 403-404

Crenicarpus n. gen.

Diagnosis. Manca-II. Pleon with five free pleonites, as wide as pereon. Antenna with six articles. Labrum conical, not laterally compressed. Maxillule endite with five terminal spiniform setae. Maxilliped palp article-3 with three long inner setae; endite naked. Cheliped merus with a cluster of long, simple setae; carpus with several crenulations on ventral margin and outer surface; propodal palm without fold but with a lobe covering portions of the fixed finger and dactylus; fixed finger and dactylus twisted in opposition, fixed finger with one or two ventral seta (in manca) and two dorso-lateral setae. Pereopod 1–3 coxa with seta; seta attached to base of dactylus slightly longer than combined length of dactylus and unguis. Pereopod 4–5 merus, carpus and propodus with spiniform setae with simple tips, merus with two, and carpus and propodus with three of these. Pleopods absent. Uropod exopod fused to the middle portion of the basal article, with two setae (one long and one short); endopod two-articled.

Etymology. From Latin crena, meaning ‘notch or rounded projections’ and carpus ‘wrist’, alluding to the crenulate carpus of the cheliped.

Remarks. The multiple setae on the cheliped merus are unique among anarthrurids and indeed all other tanaidomorphans outside of the Leptocheliidae Lang. The shape of the chela, with its distal fold, is closest in form to that of Anarthruropsis galathea Lang. It is highly distinctive and will be more or less identical in adult specimens.