Ljudmilena callosa Ruud, Menkhorst &amp; Neubert, 2016, spec. nov.
Creators: name: Ruud, A. Bank
name: Menkhorst, Henk P. M. G
name: Neubert, Eike
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Vitrinidae
Ljudmilena
Ljudmilena callosa

description: <i>Ljudmilena callosa</i> spec. nov. (Fig. 8) Type locality &amp; type specimens. – Turkey, Vilayet Artvin, Kaymaz (= 18 km SW. Yusufeli), left bank Çoruh Nehri, 770 m (40.712°N 41.392°E), E. Neubert leg., 28.vii.1988. Holotype NMBE 544659, paratypes NMBE 544660/&gt;50, HMK/2, RBA/2, ZMH/2. Diagnosis. – A dextral <i>Ljudmilena</i> species with a prominent white thickening on the basal part of the apertural wall and with an oblique palatalis superior; a columellaris is missing. Description. – Shell dextral, somewhat cylindrical, with a low conical upper part. Umbilicus open, but very narrow. The 7.9-9.5 whorls are slightly convex with a moderately shallow suture; the whorls of the upper part of the shell are slightly more convex. The last 3-4 whorls are almost equal in width; the last whorl attenuates towards the base. Teleoconch with irregular, fine, oblique striae; there are no spiral striae. Shell rather solid, somewhat translucent (in fresh specimens the curled columella can be vaguely seen), horny yellow coloured, with a whitish band behind the peristome. The last whorl with a clear impression at the position of the palatalis superior. Aperture irregular U-shaped to V-shaped, whitish inside. Peristome thickened by a labial callus, reflected over its entire length. The columellar and palatal insertion of the peristome is connected by a clear callus, which is most prominent near the columellar insertion. The subangularis is vertically pointing downwards and is connected with the palatal peristome by a callus. The subangularis is connected to the parietalis by a thin callus; this connection is not always present. Parietalis prominent, but deeply recessed. There is no spiralis. Palatalis superior very prominently developed, but not deeply recessed; it is situated quite low on the palatal peristome (i.e. it is close to the position of the infrapalatalis) because it is not placed horizontally but rather at an angle (oblique). There is no infrapalatalis, basalis or columellaris. The columellar ledge is prominent, curled and truncated; it reaches below the middle of the columellar side of the aperture. In frontal view the columellar ledge looks like a supracolumellaris. The apertural wall has a prominent white thickening (callus) ranging from behind the palatalis superior to the end of the truncated columellar ledge. Measurements (n = 8). – H = 5.9-7.8 (mean 6.7); LWH = 3.0-3.7 (mean 3.4); MH = 2.0-2.7 (mean 2.3); LWD = 2.9-3.3 (mean 3.1); LWM = 2.8-3.2 (mean 3.0); MD = 1.7-2.0 (mean 1.8); NW = 7.9-9.5 (mean 8.4). Localities. – Known from the locus typicus only (see above). Derivatio nominis. – The name refers to the thickened basal part of the aperture. Differentiation. – <i>Ljudmilena callosa</i> differs from the next species, <i>L. mariannae</i> spec. nov., by the less slen- der and less cylindrical shell, the somewhat more prominent and densely arranged obliquestriae, the oblique palatalis superior, the straight (not commashaped) subangularis which is connected (but not fused) with the parietalis, the lack of a columellaris, and the more thickened callus at the basal part of the apertural wall. <i>Ljudmilena sieversi</i> has more convex whorls, a triangular-rounded aperture, and a less well developed subangularis; a columellaris is always present. <i>Ljudmilena cespitum</i> is more spindle-shaped and has more convex whorls, the aperture is more V- shaped, the columellaris is always present, and the callus at the basal part of the apertural wall is less distinctly thickened.
description: Published as part of <i>Ruud, A. Bank, Henk P. M. G Menkhorst &amp; Eike Neubert, 2016, Descriptions of new and little-known land snail taxa from Turkey, and establishment of a new genus (Gastropoda, Pulmonata: Lauriidae, Enidae and Vitrinidae), pp. 5-30 in Basteria 80 (1)</i> on pages 15-16, DOI: 10.5281/zenodo.439745