Ena menkhorsti Hausdorf and Bank, 2001

Hausdorf, B, 2001, The genus Ena in Turkey, with remarks on its phylogenetic relationships (Gastropoda: Buliminidae), Journal of Natural History 35, pp. 1627-1638 : 1634-1635

Ena menkhorsti Hausdorf and Bank , sp. n.

(gures 3, 6, 9, 13)

Shell (gure 3). Elongated oval; with 6.5–8.5 slightly in ated whorls; moderately thick-walled; teleoconch with more or less coarse growth ridges crossed by irregular incised spiral striae producing a granulated sculpture; brownish corneous; subtranslucent; the body whorl does not ascend towards the aperture; aperture oval, edentate; peristome slightly expanded, re exed and moderately thickened on the inside; palatal insertion of the peristome connected with the columellar edge by a thin callus; rimate or umbilicus open.

Measurements. 5 km N of Tamdere (n 510): D: 6.9–8.0 mm, mean 57.5 Ô 0.3 mm; H: 15.5–19.5 mm, mean 517.2 Ô 1.1 mm; D /H: 0.395 –0.516, mean 50.439 Ô 0.035.

Genitalia (gures 6, 9). The penial appendix inserts at the distal section of the penis. The appendix sections A, A and A are distinctly delimited, whereas there 1 2 3

is no marked boundary between the sections A and A. The appendix retractor 4 5

inserts at the proximal section of section A. The penial retractor inserts at the 1

proximal section of the penis. Both retractors insert close to each other at the diaphragm. A very long and slender imperforate penial papilla inserts at the proximal end of the penis. There is a short groove in the proximal part of the penial papilla facing the opening of the epiphallus. There is a V-shaped structure with two longitudinal ridges at the penial wall behind the penial papilla. The lateral and distal wrinkled margins of this structure are detached from the penial wall. Besides, the penial wall is sculptured with irregular longitudinal ridges. There is a spur-shaped caecum at the middle section of the very long epiphallus. The agellum is moderately short. The vagina is shorter than the penis. The free oviduct is longer than the vagina. The diverticulum of the bursa copulatrix is more than twice as long as the bursa and its duct proximally of the branching point.

Remarks. Ena menkhorsti diOEers from Ena nogellii (Roth) in the broader shell with a usually slightly weaker sculpture, and in the inner structures of the penis, especially the V-shaped structure behind the very long penial papilla. No constant diOEerences have been found between the proportions of the various sections of the genitalia, which are very variable in both species.

The two converging folds in the penis of Ena nogellii , which are distally detached from the penis wall, are in the same position as the V-shaped structure in the penis of Ena menkhorsti and are therefore probably homologous to that structure. A detachment of such structures is not known from other Ena species or related genera. Therefore, the distal detachment of these structures is a synapomorphy of Ena menkhorsti and Ena nogellii , indicating that they are sister species.

B. Hausdorf and R. A. Bank (Hoofddorp, The Netherlands) are joint authors of this new species.

Etymology. The species is named in honour of Dipl.-Ing. Henk P. M. G. Menkhorst, Krimpen aan de Ijssel, who discovered it.

Type locality. V. Giresun: rocks 5 km N of Tamdere , DE48 .

Distribution and material (gure 13). Ena menkhorsti is widespread in the eastern Pontic region of Turkey between the Vilayets Tokat and Ordu in the west and the

V. Rize in the east. Several specimens of Ena menkhorsti and of Ena nogellii have been found sympatrically at rocks 5 km N of Tamdere in the V. Giresun.

V. Ordu: 12 km N of G ürgentepe, CF 92 (M EN) . V. G iresun: 5 km N of Tamdere , D E48 (det. anat.; holotype N N M, leg. H. M enkhorst, 23 July 1990, measurements: D 57.7 mm, H 517.2 mm; MEN; ZMH 2810 ) ; Giresun 49 km towards Şebin Karahisar, 800 m alt., DE49 (det. anat.; NBE) ; Giresun 75 km towards Şebin K arahisar, 1500 m alt., D E57 (N BE) ; 8 km S of D ereli, D F 50 (M EN); 12 km S of G iresun, D F 51 (M EN); 15 km S of G iresun, D F 51 (N BE); 7 km S of the mouth of the DogÏankent Çayõ, DF 83 ( NBE) ; mouth of the DogÏankent Çayõ 30 km towards Torul, DF 91 ( NBE) . V. Trabzon: 3.5 km N of Tonya , EF 22 ( IZPAN) ; 10–13 km SSE of Maçka , EF 51 ( IZPAN) ; 35 km S of branch from OF towards Bayburt, S of Ataköy , F F 00 ( NBE) . V. Rize: 21 km S of Çamlihemşin , 870 m alt., F F 62 (N BE) . V. Tokat: G ökdere, CE08 (M EN) .