Lactiforis takii (Kuroda, 1928)

Salinator takii Kuroda, 1928: 11, pl. I; Tanaka 1959: 354, figs. 1–11; Kosuge 2000: 19; Fukuda & Kosuge 2000: 140, fig. 6.1.

Type material: Japan, Kyushu: Fukuoka Prefecture, on the coast of Kurosaki, Ariake Inland Sea, muddy bottom, collector unknown. Holotype deposited in Faculty of Science, Kyoto University, not examined.

Other material examined: Japan, Kyushu: Fukuoka prefecture, estuary of the Okihata River (flowing into the Ariake Inland Sea), very soft mud tidal-flat, 1 May 2004, T. Ishibashi (AMS C.446490); Oita prefecture, estuary of the Kakise River (flowing into Seto Inland Sea), soft mud tidal-flat, 28 Dec 2003, T. Wada (AMS C.446491).

Redescription: Shell (Fig. 2 L): Fragile, opaque, spire very short, conical, diameter to 7 mm. Exterior pale grey to brown, unbanded or sometimes with one to three dark brown spiral bands, lacking differentiated colouring at umbilicus.

Operculum: Thin, pale yellow, corneous with fan-shaped white deposit on interior surface around nucleus and along outer edge, visible from exterior. Columellar edge of operculum concave; nucleus eccentric, paucispiral.

External morphology: Head-foot dark grey in formalin-preserved specimens, with diffuse stripe of black pigment on central snout and around genital aperture; mantle solid black.

Mantle organs: As for L. tropicalis sp. nov.

Digestive system: As for A. crenata, but proportionally smaller.

Radula (Figs. 10 E, F): Central and lateral teeth absent, marginal teeth continuous across radula with approximately 25 on each side; unicuspid, elongate, narrow, with recurved tips.

Central nervous system (Fig. 12 D): As for L. tropicalis sp. nov. but visceral ganglion adjacent to right parietal ganglion, with connective not visible.

Reproductive system (Fig. 14 G): As for L. tropicalis sp. nov., but with following differences: Prostatic gland uniform colour for entire length, crimson tissue at proximal base absent. Spermovipositor short, thickened tube. Muscular ridge on left side of spermovipositor sheath.

Distribution and habitat (Fig. 1): Ariake Inland Sea, Kyushu, Japan. Also found in the Seto Inland Sea, Kyushu, though this population may be introduced (H. Fukuda, personal communication). Found on very soft mud on tidal-flats.

Remarks: Although the development (Tanaka 1959) and ecology (Kosuge 2000) of L. takii have been studied, the large anatomical differences between this genus and other amphibolids have not been addressed. Fukuda & Kosuge (2000) cited earlier reports that the radula of L. takii lacks central teeth, recognising that this probably merited generic (or even subfamilial) distinction—but in the absence of comparable data for other amphibolids no name was proposed. Lactiforis takii is separated from L. tropicalis sp. nov. by the uniformly coloured prostatic gland and grey shell. It has a very limited distribution in the Ariake Sea, Japan and is considered critically endangered (Fukuda & Kosuge 2000).