Aplysia nigrocincta von Martens, 1880

アプリシア・ニグロチンクタ Aplysia nigrocincta
Photographed by
KIMOTO Nobuhiko
Location
Sakimotobu, Hontou hokubu(Iejima・Minnajima・Sesokojima), Okinawa, Japan
Date
2019/04/12
Length
8mm
Depth
10.0m
Water temperature
22.0℃

External anatomy

Animal elongate, wider in visceral region, narrowing relatively abruptly towards head and tail; visceral hump proportionally very large, rounded, well-differentiated from rest of body, occupying more than 1/3 of body length; mantle foramen large, oval, on posterior left side of visceral hump, not elevated; parapodia narrow, fused posteriorly, typically joined anteriorly, forming a conspicuous fold mid-length; rhinophores and oral tentacles relatively short, enrolled, with small projections in oral tentacles; siphon wide, relatively short, protruding slightly above parapodia. Colour highly variable, reddish to brown or black, with or without markings or spots; parapodia edge different from body colour, bluish or white; rhinophores and oral tentacles tips same colour as parapodia edge; mantle foramen with or without dark inner edge, sometimes interrupted with white patches.

Remarks

Members of species complex 3 (the A. elongata– nigrocincta species complex) are characterized by having proportionally shorter and wider bodies than other species of A. parvula s.l. Also, these animals possess short, flattened penises, with two retractor muscles. Species complex 3 is well supported in both mtDNA and nDNA phylogenetic analyses and contains three distinct clades, each recovered as a distinct species in the ABGD analysis.

References