Theodoxus altenai Schuett, 1965 Figure 4A-G

Theodoxus (Theodoxus) altenai Schütt 1965: 46-49, pl. 1, fig. 4; Schütt and Şeşen 1992: 66; Yıldırım 1999: 885.

Theodoxus altenai: Roth 1987: 75; Kebapçı and Yıldırım 2010: 77; Gürlek et al. 2019: 2993; Glöer 2019: 37, fig. 19.

Type locality.

Lake Kırkgöz, Kırkgöz Kaynaği spring complex, Döşemealtı, Antalya, Turkey.

Type material.

Holotype (RNL V.56 /1) and paratypes (RNL V.56) are stored in NMNL. Additional paratypes are stored in ZSM (ZSM /Mol - 20013211.00) .

Remarks.

The phylogenetic results based on mtDNA and nDNA (Fig. 2) suggest T. altenai Schütt, 1965 shares a close sister relationship with T. anatolicus ( Récluz, 1841), where the two species likely diverged in the early Pleistocene (Sands et al. 2019a; Fig. 2). The pseudo-apophysis on the operculum of T. altenai is strongly curved and depressed and lies in the plane of the right adductor, while in T. anatolicus the pseudo-apophysis is more diagonal and less depressed (Figs 4, 5). Schütt (1965) wrote in his original description of T. altenai that there is no pseudo-apophysis but a short strongly curved depressed lamella instead. Furthermore, the periostracum colouration of T. altenai and T. anatolicus can be differentiated by brown and ivory checks as opposed to being uniformly black in the latter (Figs 4, 5). Moreover, the columellar plate extends beyond the shell margin in T. altenai (Figs 4, 5).

Distribution.

All reliable records of this species were attributed to the Kırkgöz Kaynaği spring complex around Döşemealtı, Antalya, Turkey ( Schütt 1965; Geldiay and Bilgin 1969; Bilgin 1980; Yıldırım 1999; Kebapçı and Yıldırım 2010; Gürlek et al. 2019; Fig. 3A). However, Sands et al. (2019a) indicated the species is also present at the Düden Waterfall, Varsak Karşıyaka, Antalya, Turkey (Fig. 3A).