Leiostyla eikenboomi, Ruud, A. Bank, Henk P. M. G Menkhorst & Eike Neubert, 2016

Ruud, A. Bank, Henk P. M. G Menkhorst & 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), Basteria 80 (1), pp. 5-30 : 8

Leiostyla eikenboomi spec. nov. ( Fig. 3 )

Type locality & type specimens. – Turkey, Vilayet Karabük, Suçatı Tüneli 9 km ESE. Yenice , 190 m (41.1897°N 32.4349°E), H.P.M.G. Menkhorst leg., 22.x.2008. Holotype NMBE 544682 , paratypes NMBE 544644/2 .

Diagnosis. – A conic, densely ribbed Leiostyla species with a prominent angular lamella, as well as a prominent parietalis, palatalis inferior, and columellaris; a basalis and supracolumellaris is missing and there is a prominent two-peaked thickening between the columellar insertion of the peristome and the angular lamella.

Description. – Shell dextral, conic in outline, with closely, distinctly and regularly, oblique ribbing; there are no spiral striae. The 6.7-7.2 whorls are convex and separated by a deep suture. Shell rather solid, not or hardly translucent, dark horn-coloured. The last whorl has a lengthy but shallow gutter, corresponding in its position to the palatalis inferior on the outer wall, but there is no distinct basal keel. Umbilicus open, deep and narrow. Peristome strongly reflected at right angles to form a flat, thickened, somewhat yellowish coloured lip. Columellar and palatal insertion connected by a clearly visible parietal callus. Angular lamella prominent, high, without appendages; it almost reaches the border of the parietal callus. The angular lamella is fused with a sharp, triangle-like subangularis that faces the palatal wall and that on its turn is fused with the palatal insertion of the peristome. The subangularis creates a small sinulus. A small sinulus at the columellar insertion of the peristome is created by a two-peaked prominent thickening situated below the border of the parietal callus. Parietalis prominent, high, rather deep inside the aperture; it is not connected with the angular lamella. Palatalis inferior very long and well developed; it just stops in front of the lip (i.e. it does not fuse with it). A very small, dot-like palatalis superior is present just above the anterior end of the palatalis inferior, close to the thickened lip. The columellaris is horizontally projected above the middle of the columellar side of the aperture. There is a marked thickening below the parieto-palatal angle of the peristome.

Measurements (n = 2). – Holotype: H = 3.4; LWH = 1.8; MH = 1.4; LWD = 1.9; LWM = 2.0; MD = 1.2; NW = 7.2. Paratype: H = 3.3; LWH = 1.8; MH = 1.4; LWD = 1.9; LWM = 2.1; MD = 1.3; NW = 6.7.

Localities. – Known from the locus typicus only (see above).

Derivatio nominis. – Named after Joop C.A. Eikenboom, a well-known Dutch malacologist and for forty years an inspiring friend of the second author.

Differentiation. – Leiostyla superba differs from L. eikenboomi by its more densily packed and finer ribbing, the less conical outline, the denticulate peristome, the presence of a basalis and supracolumellaris, the more prominent palatalis superior, the more prominent tooth-like thickening of the palatal peristome just above the palatalis superior, and the missing of a two-peaked thickening below the border of the parietal callus. Leiostyla zilchi differs from L. eikenboomi by the presence of a basalis and supracolumellaris, the more developed palatalis superior, and the missing two-peaked thickening below the border of the parietal callus.

Figures

Figs 1 - 3. Leiostyla taxa from Turkey. 1, Leiostyla paphlagonica paphlagonica Hausdorf 1990, holotype SMF 307492 (4.0 mm), Turkey, Vil. Kastamonu, Kapısuyu. 2, Leiostyla paphlagonica subangulosa subspec. nov., holotype NMBE 544659 (H = 3.7 mm), Turkey, Vil. Amasya, 10.3 km NE. Amasya. 3, Leiostyla eikenboomi spec. nov., holotype NMBE 544682 (H = 3.4 mm), Turkey, Vil. Karabük, Suçatı Tüneli 9 km ESE. Yenice. All photographs Bochud & Neubert, × 15.