Staja lycica (Oppenheim, 1919)

Neubauer, Thomas A. & Wesselingh, Frank P., 2023, The Early Pleistocene freshwater mollusks of the Denizli Basin (Turkey): a new long-lived lake fauna at the crossroads of Pontocaspian and Aegean-Anatolian realms, Zitteliana 97, pp. 53-88 : 53

Staja lycica (Oppenheim, 1919)

Fig. 11A-I, S, T

*1919 Fluminicola (Gillia) lycica sp. nov. - Oppenheim: 117-119, pl. 5, fig. 2, 2a.

1923 Amnicola (Staja) lycica (Oppenheim) - Wenz: 2086.

1982 Pseudamnicola (Staja) lycica ( Oppenheim 1919) - Willmann: 313-314.

? 2008 Pseudamnicola orientalis (Bukowski, 1895) - Wesselingh et al.: 865, fig. 5(8a-c).

Material.

Sample 1: 21 specimens and 5 fragments (RGM 1310854), 1 specimen (RGM 1365351), 2 specimens (SNSB-BSPG 2023 XII 14); sample 2: 1 specimen (RGM 962619), 1 specimen (SNSB-BSPG 2023 XII 15).

Type locality.

Tlos (an ancient city in Muğla Province near Seydikemer), Turkey; probably Eşen Formation ( Kocaçay Member), Zanclean, Lower Pliocene.

Description.

Ovoid, slender to slightly broader shell with up to 5 moderately convex whorls. Protoconch low-domed, consisting of c. 1.2 apparently smooth whorls; P/T boundary marked by growth rim and onset of growth lines. Last whorl attains 79-82% (n = 3) of total height. Aperture oblique, ovoid to almost elliptical, weakly inclined in lateral view. Inner lip touches base of penultimate whorl but weakly detaches in some specimens near adapical tip and base, leaving very narrow umbilicus; latter occasionally opens into narrow canal that runs along inner lip toward base and is demarcated by weak fasciole. Shell surface smooth except for numerous faint spiral furrows detected in well-preserved specimens.

Dimensions.

6.08 × 4.24 mm (Fig. 11A-C, S ; RGM 962619), 3.90 × 2.76 mm (SNSB-BSPG 2023 XII 15; Fig. 11D, T ), 4.41 × 2.83 (Fig. 11G-I ; RGM 1365351).

Remarks.

Here, we combine a variety of morphologies under the name Staja lycica . This includes a comparatively large, broad morphotype with highly convex whorls (Fig. 11A-C, S ; RGM 962619), which matches the features illustrated by Oppenheim (1919). Also the overall size, the faint spiral furrows indicated by Oppenheim, as well as the slightly inclined aperture fit well. The very weak detachment of the aperture from the base of the last whorl and the "layered peristome" referred to by Oppenheim and shown in his illustrations match a morphotype that is more slender and smaller but otherwise fits the original description and illustration and cannot be reasonably distinguished (Fig. 11G-I ). Since Oppenheim’s type material seems to be lost, topotypic material from the Eşen Basin is needed to clarify the identity and variability of this species.

Staja orientalis (Bukowski, 1896) from the Pliocene Istrios Formation of Rhodes differs from S. lycica in the even broader shape, larger size, and presence of an umbilicus (Fig. 11E, F ). However, some specimens of S. orientalis from Attica (mainland Greece) illustrated by Willmann (1982, fig. 3i-l) closely resemble S. lycica. Willmann (1982) even hypothesized that both species might be synonymous. A thorough revision of the Staja lycica - Prososthenia orientalis species group is required to settle these uncertainties. To fix the identity of S. orientalis , we hereby designate the specimen illustrated by Bukowski (1896, pl. 10, fig. 1) as the lectotype (IGUW 1895 XII/45; Fig. 11F ).

The specimen from the Kolankaya II fauna of the upper Kolankaya Formation attributed to S. orientalis by Wesselingh et al. (2008) rather range within S. lycica ; they even show the slightly detached aperture as mentioned by Oppenheim.

Distribution.

So far only known from the type locality in the Eşen Basin ( Oppenheim 1919), which is of Late Pliocene age according to ( Alçiçek et al. 2019), and the Early Pleistocene of the Denizli Basin (this study).

Figures

Figure 11. The Staja - Falsipyrgula species complex of the Kolankaya I fauna. A-C. S. Staja lycica (Oppenheim, 1919), RGM 962619, sample 2. D, T. S. lycica, SNSB-BSPG 2023 XII 15, sample 2. E. Staja orientalis (Bukowski, 1896), lectotype (designated herein), IGUW 1895 XII / 45, between Profilia and Istrios, Rhodes, Greece, Istrios Formation (Pliocene). F. S. orientalis, paralectotype, IGUW 1895 XII / 46, same locality and stratum. G-I. S. lycica, RGM 1365351, sample 1. J-L, U. Staja? cibyratica (Spratt & Forbes, 1847), RGM 962621, sample 2. M-O. S.? cibyratica, RGM 962620, sample 2. P-R. S.? cibyratica, SNSB-BSPG 2023 XII 16, sample 2. Scale bars: 1 mm (A-R); 100 μm (S-U).