Mesolamprops abyssalis Reyss, 1978a: 7–10, fig. 3A–F, fig. 4A–G.
Type material. Deposition unknown. Gay Head, Bermuda Transect, 36°23’N, 67°58’W. Not seen.
Diagnosis. Carapace without lateral ridges, dorsal crest entire. Pleon not including telson equal to carapace and pereonites together. Telson without lateral setae, 5 terminal setae. Adult male antennal flagellum short, not extending to end of pereon; pleopod rami equal, uniarticulate.
Depth. 4667–4862 m.
Distribution. North Atlantic, 35– 37°N, 63– 68°W.
Remarks. The only other species in Mesolamprops that have five terminal setae on the telson are M. bispinosus and M. japonicus, but in M. abyssalis the terminal setae are nearly equal in the female, and in the male the central seta is the longest. However, in M. bispinosa and M. japonicus the outer most pair of terminal setae are the longest, and the inner pair are shorter than the central seta. In addition, the pseudorostrum is distinctly produced in M. abyssalis, while M. bispinosa and M. japonicus hasve no obvious anteriorly projecting pseudorostrum.