Valvata colbeaui Roffiaen 1868

Valvata colbeaui Roffiaen, 1868 Fig. 1 B Valvata colbeaui Roffiaen, 1868: 81, pl. 1, fig. 1. Type material. RBINS I.G.9154 / MT.2041: 2 syntypes, ex Roffiaen coll., ex de Cort coll. Type locality. Switzerland: Iseltwalt, Lake Brienz (Brienzersee). “ Lac de Brientz à Iseltwalt ” (Roffiaen 1868: 81). Taxonomic status. Junior synonym of Valvata antiqua Morris, 1838 (see below). Discussion. According to the label, the specimens stem from the collection of Roffiaen, they are from the type locality (Iseltwalt) and are labelled “ types ”. Thus, they can be considered syntypes. It is also worthwhile to note that the lot first became part of de Cort’s collection before being acquired by the RBINS. Roffiaen’s shells correspond reasonably well to Valvata antiqua Morris, 1838, a morphospecies for which genetic data remains unavailable and, consequently, a variety of opinions on its taxonomic status and rank exists among malacologists. It is sometimes regarded as merely an infraspecific morph of V. piscinalis thought to develop in large lakes, including the Alpine lakes (Falniowski 1989; Piechocki and Wawrzyniak-Wydrowska 2016). Falniowski (1989: 73) considered this morph Valvata piscinalis f. antiqua colbeaui, an endemic to Lake Geneva. Glöer (2002) ranked it as a subspecies of V. piscinalis, but this solution is untenable since the ranges of V. piscinalis piscinalis and V. piscinalis antiqua broadly overlap. The latest publications tend to accept V. antiqua as a species, distinct from V. piscinalis (Vinarski and Kantor 2016; Glöer 2019), although a DNA assessment of this insufficiently studied snail is urgently needed. Valvata piscinalis (O. F. Müller, 1774) is a widespread species in Europe, and while it more usually displays a wide shell with an ample body whorl and aperture, more trochoid forms with comparatively smaller apertures are also known (Turner et al. 1998; Glöer 2002, 2019; Vinarski et al. 2013). The present specimens at first seem to fit within the range of conchological variation displayed by that species, though they are smaller at the same number of whorls. The largest specimen available (Fig. 1 B), which is the most similar to the published illustration (Roffiaen 1868: pl. 1, fig. 1), has a more strongly trochoid shell, with narrower and less bulging whorls.