Valvata sp. 1

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. 1

Fig. 14E-L, U-W

Material.

Sample 1: 1 specimen (RGM 1365352), 1 specimen (SNSB-BSPG 2023 XII 21); sample 2: 1 specimen (RGM 962695), 1 specimen (SNSB-BSPG 2023 XII 22).

Dimensions.

1.60 × 2.48 mm (RGM 962695; Fig. 14I-L, W ), 1.48 × 2.18 mm (RGM 1365352; Fig. 14E-H, U, V ).

Remarks.

This species is characterized by a small, low-trochiform shell with relatively large, nearly circular aperture, slightly raised, bulbous apex, wide umbilicus, and moderately distinct growth lines. The protoconch bears the typical valvatid pattern, with numerous distinct spiral ridges crossed by weaker axial, u-shaped ridges, creating a wavy impression (Fig. 14U, V ).

The material closely resembles the Pliocene Valvata gregaria Bukowski, 1896 (p. 25-28, pl. 8, figs 7, 8) from Rhodes in terms of the shell size and shape, the relatively large aperture, and low number of whorls (see also Willmann 1981, p. 77, textfig. 25). However, the lectotype and paralectotype of that species (designated by Willmann 1981) show a depressed and unevenly coiled spire (Fig. 14M-T ), while the Denizli specimens has a bulbous, almost pointy apex and a slightly more ovoid aperture.

Given the low amount of specimens available for comparison and assessing morphological variability, the perhaps not fully adult state of the specimens, as well as the low number of features, we do not describe a new species, although we could not detect any extant or late Cenozoic species that matches our material.

Figures

Figure 14. Valvatidae of the Kolankaya I fauna. A-D. Valvata piscinalis (Mueller, 1774), RGM 962694, sample 3. E-H, U, V. Valvata sp. 1, RGM 1365352, sample 1. I-L, W. Valvata sp. 1, RGM 962695, sample 2. M-P. Valvata gregaria Bukowski, 1896, lectotype (designated by Willmann 1981), IGUW 1895 XII / 25, Skiadhi Monastery, Rhodes, Greece, Istrios Formation (Pliocene). Q-T. Valvata gregaria Bukowski, 1896, paralectotype, IGUW 1895 XII / 26, same locality and stratum. Scale bars: 1 mm (A-T); 100 μm (U-W).