Aplysia japonica G. B. Sowerby II, 1869

Golestani, Haleh, Crocetta, Fabio, Padula, Vinicius, Camacho-García, Yolanda, Langeneck, Joachim, Poursanidis, Dimitris, Pola, Marta, Yokeş, M. Baki, Cervera, Juan Lucas, Jung, Dae-Wui, Gosliner, Terrence M., Araya, Juan Francisco, Hooker, Yuri, Schrödl, Michael & Valdés, Ángel, 2019, The little Aplysia coming of age: from one species to a complex of species complexes in Aplysia parvula (Mollusca: Gastropoda: Heterobranchia), Zoological Journal of the Linnean Society 187, pp. 279-330 : 314-316

Aplysia japonica G. B. Sowerby II, 1869 : [207], pl.

5, figs 16A–B. Type locality: Japan Seas. Three syntypes: Dry shells 18–25 mm long, Hugh Cuming collection (NHMUK 1958.1.9.267-9).

Aplysia japonica Clessin, 1899: 21 , pl. 4, figs 6–7 (non Aplysia japonica G. B. Sowerby II, 1869 ). Aplysia sieboldiana Clessin, 1899: 54 (new name for Aplysia japonica Clessin, 1899 ). Type locality: ‘Hakotade’ [=Hakodate, Hokkaido, Japan]. Syntype: August 1894, dry shell 6.2 mm long (ZMB Moll 38136).

Other material examined Gyeongsangbuk-do, South Korea, 24August2011, onespecimen 22 mmpreserved length, leg. D.-W. Jung ( CPIC 02175 , isolate HG129); 12 August 2012, one specimen 28 mm preserved length, leg. D.-W. Jung ( CPIC 02179 , isolate HG133); 24 August 2012, one specimen 21 mm preserved length, leg. D.-W. Jung ( CPIC 02180 , isolate HG134) . Jeju-do, South Korea, 28 April 2013, one specimen 23 mm preserved length, leg. D.-W. Jung ( CPIC 02176 , isolate HG130). Southern Hokkaido, Japan, 12 September 2014, one specimen 20 mm preserved length, leg. T. Lindsay ( CPIC 01367 , isolate HG61) .

Description

External anatomy: Animal elongate, wider in visceral region, narrowing gradually towards head and tail; visceral hump proportionally very large, elongate, 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 broad, fused posteriorly, typically joined anteriorly, forming several folds; rhinophores and oral tentacles relatively short, enrolled, with small projections in oral tentacles; siphon wide, relatively short, protruding slightly above parapodia. Colour reddish to brown, with white dots aggregated in clusters; parapodia edged in red, with a broad submarginal black band, often with white dots; rhinophores and oral tentacles tips red with submarginal black area dotted in white; mantle foramen with dark inner edge.

Internal anatomy: Shell broad, oval, widest near centre; posterior left side regularly curved, posterior right side concave adjacent to protoconch; rachidian tooth with robust, triangular central cusp bearing multiple sharp denticles, 3–4 lateral cusps on each side of central cusp, typically lacking denticles; lateral teeth with central cusp denticulated on both sides, larger tooth or secondary cusps near each side of base; up to four simple outer teeth. Radular formula 27 × 3.9.1.9. 3 in a 23 mm preserved length specimen from South Korea ( CPIC 02176, isolate HG130) and 27 × 4.9.1.9. 4 in a 21 mm preserved length specimen from South Korea ( CPIC 02180, isolate HG134). Jaw with cylindrical, elongated elements with single cusp at tips. Penis elongate, robust, with two retractor muscles and tip with a single hooked papilla.