Valvata sp. 3

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

Valvata sp. 3

Fig. 15Q-T

Material.

1 specimen (RGM 962697) from sample 2.

Dimensions.

2.79 × 2.92 mm.

Remarks.

As for the previous species, this one is only known from a single specimen. It is characterized by a relatively small, globular shell with short apex and bulbous, regularly convex body whorl. The aperture is broken but appears to be nearly circular, the umbilicus is wide and the shell surface bears distinct orthocline growth lines. The protoconch is about half a whorl, weakly heterostrophic and bears weak signs of an originally spiral sculpture. The transition to the teleoconch is marked by a broad, shallow furrow and the onset of regular coiling.

The spherical shape with short apex and distinct growth lines reminds of the extant Valvata montenegrina Glöer & Pešić, 2008 from Lake Skadar and Podgorica (Montenegro). The Balkan species is, however, much larger (6-7 mm high, 6.2-6.8 mm wide; Glöer 2019) and slightly less broad than the Turkish specimen. Our specimen also reminds of juvenile V. piscinalis , but the shape is too conical and the umbilicus to wide with a too long straight upper flank. Given the generally large variability of Valvata piscinalis we cannot exclude the option that the specimen belongs to that species, but we consider it unlikely. The Turkish Quaternary species Valvata orientalis Fischer, 1866 (see above) shares the broad shape but has a higher apex and a relatively smaller aperture (Fig. 15E-G ).

Although we could not find any species with which this one can be identified, we refrain from introducing a new name because of the low amount of material available, the incompleteness of the shell, and the small number of distinct morphological features.

Figures

Figure 15. Valvatidae of the Kolankaya I fauna. A-D, H. Valvata sp. 2, RGM 962690, sample 1. E-G. Valvata orientalis Fischer, 1866, lectotype (designated herein), MNHN. F. B 41478, Lake Buldur, Quaternary. I-L. Valvata skhiadica Bukowski, 1896, lectotype of V. monachorum Bukowski, 1896 (designated by Willmann 1981), IGUW 1895 XII / 30, Skiadhi Monastery, Rhodes, Greece, Istrios Formation (Pliocene). M-P. V. skhiadica, lectotype (designated by Willmann 1981), IGUW 1895 XII / 27, same locality and stratum. Q-T. Valvata sp. 3, RGM 962697, sample 2. Scale bars: 1 mm (A-S); 100 μm (T).