Xestopyrguloides? sp.

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

Xestopyrguloides? sp.

Fig. 10S-U

Material.

1 fragment (RGM 1365347) from sample 2.

Remarks.

A second species is tentatively referred to the genus Xestopyrguloides . A single incomplete shell is available, containing the last 2.5 whorls and the upper part of the aperture. The shell is similarly elongate as Xestopyrguloides? sagitta sp. nov. and also bears a narrow basal keel, as well as the same type of growth lines. However, the shell is larger, the whorls are moderately convex, and the aperture is larger and drop-shaped. The basal keel and shape of the aperture, as well as the size, would also fit to the Greek X. neumayri and Xestopyrguloides? heldreichii (Fig. 10R ), but both species have straight-sided whorls.

The Staja - Falsipyrgula species complex

Remarks. The enormous morphological variability of the Denizli specimens, as well as other material from Turkey and Greece assigned to the genus Staja (e.g., Willmann 1982), makes a systematic classification incredibly difficult. This concerns variation in shell shape, size, and presence and expression of sculpture, which - if our assessment is correct - varies even within single species. The keeled representatives remind of and are considered to belong in the Pyrgulinae genus Falsipyrgula , while the smooth morphotypes are classically assigned to Staja , a genus that is originally described from the Late Miocene of the Pannonian Basin.

A full revision of the Greek-Turkish Staja - Falsipyrgula species complex is beyond the scope of this study. We follow the literature for the genus classifications of the known species, yet being aware of the unresolved genus concepts. A new species is placed in Falsipyrgula due to the close similarities to extant congeners.

Figures

Figure 10. Pyrgulinae (Hydrobiidae) of the Kolankaya I fauna. A-E. Prososthenia cf. Prososthenia sturanyi Prososthenia communis Willmann, 1981, RGM 962615, sample 2. F-J. P. cf. Prososthenia sturanyi Prososthenia communis, SNSB-BSPG 2023 XII 11, sample 2. K-Q. Xestopyrguloides? sagitta sp. nov., holotype, RGM 962616, sample 2. R. Xestopyrguloides? heldreichii (Fuchs, 1870), lectotype (designated by Willmann 1981), NHMW 1878 XX 28, Megara, Pliocene. S-U. Xestopyrguloides? sp., RGM 1365347, sample 2. Scale bars: 1 mm (A-D, F-I, K-N, R-T); 100 μm (E, J, O-Q).