Cepaea cf. sylvestrina Schlotheim, 1820

Salvador, Rodrigo Brincalepe, 2013, The fossil pulmonate snails of Sandelzhausen (Early / Middle Miocene, Germany): Succineidae, Testacelloidea and Helicoidea, Zootaxa 3721 (2), pp. 157-171 : 163-165

Cepaea cf. sylvestrina Schlotheim, 1820

( Figs. 14–17 )

Helix sylvestrina Schlotheim, 1820: 99 .

Cepaea sylvestrina sylvestrina: Wenz, 1923a: 690 . Cepaea sylvestrina: Truc, 1971: 282 .

Cepaea eversa larteti (in part): Gall, 1972: 10; Gall, 1973: 10 (pl.1, figs. 4–6). Cepaea silvana silvana (in part): Gall, 1972: 11.

“ Cepaea ” sp. 1. (in part): Moser et al., 2009b: 50.

Material examined. BSPG 1959 II 459 (1 spcm.), 16156 (1 spcm.), 17447 (2 spcm.), 17448 (2 spcm.), 17447 (1 spcm.), 17449 (1 spcm.), 17450 (1 spcm.), 17451 (1 spcm.), 17452 (1 spcm.), 17453 (1 spcm.), 17454 (1 spcm.), 17455 (1 spcm.), 17456 (2 spcm.), 17457 (1 spcm.), 17458 (1 spcm.), 17459 (1 spcm.), 17460 (1 spcm.), 17461 (1 spcm.), 17462 (1 spcm.), 17463 (1 spcm.), 17464 (1 spcm.), 17465 (1 spcm.), 17466 (1 spcm.), 17467 (1 spcm.), 17468 (1 spcm.), 17766 (1 spcm.), 17767 (1 spcm.), 17768 (1 spcm.), 17769 (1 spcm.), 17770 (1 spcm.), 17771 (1 spcm.), 17772 (1 spcm.), 17773 (1 spcm.), 17774 (1 spcm.), 17775 (1 spcm.), 17776 (2 spcm.), 17777 (1 spcm.), 17778 (1 spcm.), 17779 (3 spcm.), 17780 (2 spcm.), 17781 (2 spcm.).

Stratigraphic occurrence. Layers B1 (1 spcm.), B2 (2 spcm.), C (undetermined; 1 spcm.), C1 (3 spcm.), C3 (1 spcm.), D1 (4 spcm.). Moreover, 25 specimens are from excavation sites for which no profile is available, but, based on their height in the sediment and their preservation, it is possible to infer the layer of origin for some: 3 are likely from layer D, 4 from either B2 or C1, 9 from either C3 or D.

Description. Shell medium-sized, ~4 whorls, helicoid; whorls quickly but regularly growing; shell length ~2/3 its width. Protoconch flattened, smooth; transition to teleoconch unclear. Teleoconch smooth, except for growth lines. Suture well-marked. Body whorl slightly bent downwards; faint carina apparently present. Aperture prosocline, crescent-shaped; callus faint. Peristome markedly thickened and reflexed. Umbilicus imperforate. On a single specimen (BSPG 1959 II 16156) it is possible to observe, under UV light, vestiges of three colored fine parallel spiral bands, the topmost one right below the carina, the other two regularly spaced on basal portion of whorl.

Measurements (in mm). BSPG 1959 II 16156 ( Figs. 14–17 ): 4 whorls; H = 13.7; D = 19.9; h = 6.9; d = 10.0.

Previous identification of the material. Gall (1972: Nr. 20 and 21, in part): respectively, Cepaea silvana silvana (Klein) and Cepaea eversa larteti (Boissy) . Moser et al. (2009b: Nr. 64, in part): “ Cepaea ” sp. 1.

Discussion. The specimens from Sandelzhausen compare well with C. sylvestrina , but the typical specimens of the latter are taller and have a rounder profile, especially the body whorl. Moreover, typical C. sylvestrina have the apertural region bent more markedly downwards. Finally, the present specimens have a more distinct carina and less convex whorls. However, it cannot be completely excluded that these are artifacts due to preservational biases (for more, see the Discussion chapter below). The vestiges of colored bands can be seen in a single specimen of C. cf. sylvestrina and two of C. cf. eversa (see above). The pattern is trifasciate in both species, but the bands are much broader in C. cf. eversa . This trifasciate pattern occurs in recent Cepaea species and was found to be the most common one in fossils of C. sylvestrina gottschicki Wenz from Poland (Górka 2008). Cepaea sylvestrina is known throughout the Middle and Late Miocene of Central Europe.

Remarks. Truc (1971) alludes to the possibility that C. sylvestrina belongs in the genus Megalotachea. Zilch (1959–1960), however, considers Megalotachea a synonym of Cepaea s. str.

Genus Tropidomphalus Pilsbry

Tropidomphalus cf. incrassatus (Klein, 1853) ( Figs. 18–21 )

Helix inflexa Klein, 1847: 71 (pl. 1, fig. 12).

Helix incrassata Klein, 1853: 208 (pl. 5, fig. 6).

Tropidomphalus (Pseudochloritis) extinctus: Gall, 1972: 9; Gall, 1973: 10 (pl.1, fig. 1).

Tropidomphalus (Pseudochloritis) incrasstus incrassatus : Wenz, 1923a: 510; Gall, 1972: 9; Schlickum, 1976: 16 (pl. 4, fig. 56).

Tropidomphalus (Pseudochloritis) zelli : Gall, 1972: 9.

Tropidomphalus? sp.: Gall, 1972: 10; Gall, 1973: 10 (pl.1, figs. 2–3).

Tropidomphalus (Pseudochloritis) incrassatus : Kókay, 2006: 90 (pl. 34, figs. 12–14).

Pseudochloritis incrassata : Binder, 2008: 172 (pl. 3, figs. 2–4, pl. 6, fig. 2).

Tropidomphalus (Pseudochlorites) [sic] sp.: Moser et al., 2009b: 49.

Material examined. BSPG 1959 II 456 (1 spcm.), 457 (1 spcm.), 458 (1 spcm.), 16153 (1 spcm.), 16154 (1 spcm.), 16155 (4 spcm.), 16163 (1 spcm.), 17318 (1 spcm.), 17322 (1 spcm.), 17323 (1 spcm.), 17324 (1 spcm.), 17325 (1 spcm.), 17326 (1 spcm.), 17327 (2 spcm.), 17328 (1 spcm.), 17329 (1 spcm.), 17330 (1 spcm.), 17331 (1 spcm.), 17332 (1 spcm.), 17333 (1 spcm.), 17334 (1 spcm.), 17335 (1 spcm.), 17348 (1 spcm.), 17349 (1 spcm.), 17350 (1 spcm.), 17351 (1 spcm.), 17353 (1 spcm.), 17354 (1 spcm.), 17355 (1 spcm.), 17356 (1 spcm.), 17357 (1 spcm.), 17358 (2 spcm.), 17359 (4 spcm.), 17360 (1 spcm.), 17361 (2 spcm.), 17362 (1 spcm.), 17363 (1 spcm.), 17364 (4 spcm.), 17365 (1 spcm.), 17366 (2 spcm.), 17367 (1 spcm.), 17368 (1 spcm.), 17369 (1 spcm.), 17370 (1 spcm.), 17473 (1 spcm.), 17730 (1 spcm.), 17731 (1 spcm.), 17732 (1 spcm.), 17733 (2 spcm.), 17734 (2 spcm.), 17735 (1 spcm.), 17736 (1 spcm.), 17737 (1 spcm.), 17738 (4 spcm.), 17739 (1 spcm.), 17740 (1 spcm.), 17741 (2 spcm.), 17742 (1 spcm.), 17743 (1 spcm.), 17744 (1 spcm.), 17745 (1 spcm.), 17746 (2 spcm.), 17747 (1 spcm.), 17748 (1 spcm.), 17749 (1 spcm.), 17750 (1 spcm.), 17751 (3 spcm.), 17752 (1 spcm.), 17753 (1 spcm.), 17754 (1 spcm.), 17755 (1 spcm.), 17756 (2 spcm.), 17757 (4 spcm.), 17758 (1 spcm.), 17759 (1 spcm.), 17760 (1 spcm.), 17761 (1 spcm.), 17762 (1 spcm.), 17763 (4 spcm.), 17764 (3 spcm.), 17765 (1 spcm.).

Stratigraphic occurrence. Layers B (undetermined; 10 spcm.), B1 (3 spcm.), B2 (2 spcm.), C (undetermined; 5 spcm.), C1 (7 spcm.), C2 (2 spcm.), C3 (2 spcm.) and D1 (4 spcm.). Moreover, 68 specimens are from excavation sites for which no profile is available, but, based on their height in the sediment and their preservation, it is possible to infer the layer of origin for some: 1 is likely from layer B (undetermined), 1 from C (undetermined), 3 from C1, 2 from C3, 8 from D1, 13 from either B or C, 9 from either B2 or C1, and 10 from either C3 or D1. Finally, 4 specimens stem from the Grube Bergmaier site and 2 specimens completely lack locality and stratigraphical data.

Description. Shell large, 4½ whorls, helicoid to disc-shaped, with flattened spire; shell length ~1/2 its width. Protoconch (1¼ whorl) flattened, large in relation to following whorl; sculptured by fine striae dotted with weak papillae; transition to teleoconch unclear. Teleoconch sculptured by thickened growth lines and irregular weak furrows, with regularly arranged papillae. Suture deep, well-marked. Body whorl enlarged, slightly bent downwards, with conspicuous constriction right before the aperture (“extralabial depression” sensu Binder 2008). Aperture prosocline; no callus apparent. Peristome markedly thickened and reflexed, slightly covering umbilicus. Umbilicus wide.

Measurements (in mm). BSPG 1959 II 456 (incomplete specimen; Figs. 18–19 ): H = 15.9; D = 28.8.

Previous identification of the material. Gall (1972: Nr. 13–16): respectively, Tropidomphalus (Pseudochloritis) extinctus (Rambur), Tropidomphalus (Pseudochloritis) incrasstus incrassatus (Klein) , Tropidomphalus (Pseudochloritis) zelli (Kurr) , Tropidomphalus? sp. Moser et al. (2009b: Nr. 56): Tropidomphalus (Pseudochlorites) [sic] sp.

Discussion. The specimens from Sandelzhausen, despite their poor preservation, seem to conform well to the great morphological variation shown by Tropidomphalus incrassatus (Binder 2008) . This species is known from the Middle Miocene of Poland (Górka 2008), Austria, many localities in Germany (Binder 2008) and perhaps also Hungary (Kókay 2006). Some of the specimens are poorly preserved, with varying degrees of deformation, which alters the overall shell shape and its size and may influence classification as different species (for more, see the Discussion chapter below).

Binder (2008) considers the shell of Tropidomphalus, based especially on the angulation of the body whorl and aperture, an adaptation for ground-dwelling to reduce water loss in drier environments. Moser et al. (2009) suggest that the genus inhabited drier and more open habitats, having a “way of life like strong-shelled Balkanese representatives of Ariantinae ”.

Remarks. T. incrassatus is considered to belong to the subgenus Pseudochloritis Boettger, 1909. Nordsieck (1986) was the first to regard Pseudochloritis as a distinct genus, but did not offer any explanation for his decision. Binder (2008) revised the genus and separated it from Tropidomphalus basically based on the width of the umbilicus (narrow in Pseudochloritis, wide in Tropidomphalus) and protoconch sculpture. However, protoconch sculpture does not seem to be constant in each subgenera and the width of the umbilicus greatly varies even intraspecifically for specimens of different localities. As such, here we maintain the species only as T. incrassatus and question the usefulness of the subgenus Pseudochloritis.

Finally, there is some uncertainty as to the position of the genus Tropidomphalus Pilsbry inside Helicoidea, belonging either to the Elonidae or Helicidae (Zilch 1959–1960; Binder 2008; Moser et al. 2009b). Here the latter was preferred, in accordance with Binder (2008).

Figures

FIGURES 1 – 21. 1 – 2. Succinea minima (BSPG 1959 II 17471; H = 2.6 mm). 3 – 4. Palaeoglandina sp. (BSPG 1959 II 16145; H = 49.7 mm). 5. Testacella zelli (BSPG 1959 II 17689; H = 2.3 mm). 6 – 9. Klikia cf. c oarctata (BSPG 1959 II 16144; D = 9.3 mm). 10 – 13. Cepaea cf. eversa (BSPG 1959 II 16162; D = 26.0 mm). 14 – 17. Cepaea cf. sylvestrina (BSPG 1959 II 16156; D = 19.9 mm). 18 – 19. Tropidomphalus cf. incrassatus (BSPG 1959 II 456; D = 28.8 mm). 20 – 21. Tropidomphalus cf. incrassatus (BSPG 1959 II 457; D = 35.1 mm).