Lucilla subteres ( Clessin, 1877 )

Salvador, Rodrigo B., 2014, The fossil land and freshwater snails of Gündlkofen (Middle Miocene, Germany), Zootaxa 3785 (2), pp. 271-287 : 280

Lucilla subteres ( Clessin, 1877)

( Fig. 24 )

Helix (Patula) subteres Clessin, 1877: 35 .

Patula subteres: Clessin, 1885: 76 (pl. 7, fig. 6).

Pyramidula subteres: Wenz, 1923: 1062 .

Helicodiscus (Hebetodiscus) subteres: Schlickum, 1976: 11 (pl. 2, fig. 35); Schlickum, 1979: 68 (fig. 2); Gall, 1980: 65; Kókay, 2006: 74 (pl. 27, figs. 14–16).

Material examined. BSPG 1952 XVIII 4 (1 spcm.).

Description. Shell diminutive, discoid, with flattened spire. Protoconch (~1¼ whorl) flat, apparently smooth; transition to teleoconch unclear. Teleoconch smooth, but with well-marked growth lines. Whorl profile convex. Suture well-marked, deep. Whorls regularly growing. Aperture round. Umbilicus wide.

Previous identification of the material. Gall (1980: Nr. 28): Helicodiscus (Hebetodiscus) subteres (Clessin) .

Discussion. The present specimen compares well to L. subteres , a species known from Miocene (MN 5–6) sites of Southern Germany and Hungary ( Schlickum 1976, 1979; Kókay 2006). The species of Lucilla were usually classified in the genus Helicodiscus Morse and, more specifically, in the subgenus Hebetodiscus H.B. Baker. Hebetodiscus, however, was later considered a distinct genus by Bequaert & Miller (1973), which, in turn, was then regarded as a synonym of Lucilla by Falkner et al. (2002). As such, some authors (e.g., Hubricht 1985; Hotopp et al. 2010) state that this whole Helicodiscus complex should be revised. Until then, the current approach of treating Lucilla as a distinct genus (e.g., Moser et al. 2009; Gargominy et al. 2011; Welter-Schultes 2012) is followed here.

Paleoecological remarks. The two recent European Lucilla species are subterranean ( L. scintilla Lowe is even blind), living deeper in the soil than other land snails ( Welter-Schultes 2012). If the extinct species shared this habit, the increased difficulty for their preservation would explain the scarce fossil record of the genus.

Figures

FIGURE 24. Lucilla subteres (BSPG 1952 XVIII 4; D = 1.7 mm).