Toledonia limnaeoides ( Odhner, 1913 )

Ohnheiser, Lena Tina & Malaquias, Manuel António E., 2014, The family Diaphanidae (Gastropoda: Heterobranchia: Cephalaspidea) in Europe, with a redescription of the enigmatic species C olobocephalus costellatus M. Sars, 1870, Zootaxa 3774 (6), pp. 501-522 : 511-512

Toledonia limnaeoides ( Odhner, 1913)

( Fig. 8 A–D)

Ptisanula limnaeoides Odhner 1913: 1 –10.

Toledonia limnaeoides — Odhner 1939: 6. Marcus 1976: 29, 30, figs 13–18, 40, 41. Warén 1989: 20, 21, figs 4 D, F, 13 C. Burn & Thompson 1998: 948. Kantor & Sysoev 2006: 251, pl. 125 figs D, E. Høisaeter 2009: 79.

Diagnosis. Shell external, smooth. Foot posteriorly rounded, cephalic shield with tentacular lobes. Rachidian tooth present, lateral teeth plate like. Reproductive system with unbranched prostate.

Type locality. Bel Sound, Svalbard.

Material examined. 62°35'36" N, 001°13'60" E, off Ålesund, 1 spc (dissected), ZMBN 86227, H = 3.89 mm. 62°33'36" N, 000°58'54" E, off Ålesund, 1 sh, ZMBN 82279, H = 2.5 mm.

Shell ( Fig. 8 A, B): Maximum H = 3.89 mm. External; whitish transparent; globose-elongate in shape, aperture wide, spire elevated, umbilicate; shell surface smooth, faint growth lines.

Animal: Body darkish brown; foot rounded posteriorly, median furrow present, cephalic shield with two anterior lobes, eyes visible, can withdraw completely into shell ( Odhner 1913; Golding 2010).

Radula ( Fig. 8 C): Radular formula 29 x 1.1.1. Rachidian tooth denticulate. Lateral teeth plate like ( Odhner 1913; Warén 1989).

Male reproductive system ( Fig. 8 D): Short unbranched prostate emerging from short tubular penial sheath.

Ecology. Found between 10–804 m and in haddock stomachs ( Warén 1989; Høisaeter 2009) on stones, stones with hydroids and algae ( Odhner 1913). Høisaeter (2009) found the species in negative temperatures on the Norwegian continental slope.

Distribution. Barents Sea, White Sea, Laptev Sea, East Siberian Sea ( Kantor & Sysoev 2006). Warén (1989) reports this species from Greenland, Svalbard and Iceland and Høisaeter (2009) from the slope north of the Norwegian Trench at 62°30’ N.

Remarks. Toledonia limnaeoides is so far the only species of the genus found in the northern hemisphere. All other species in the genus are Antarctic, with the exception of the recently described T. warenella from New South Wales, Australia ( Golding 2010).

Figures

FIGURE 8. Toledonia limnaeoides. A. dorsal view of shell (SEM). B. ventral view of shell (automontage picture). C. detail of radular rachidian teeth (SEM). D. male reproductive system (drawing). Abbreviations: ga, genital aperture; pr, prostate; ps, penial sheath. Scale bars: A = 200 µm; B = 0.5 mm; C = 5 Μm; D = 20 Μm.