Helix (Helix) escherichi O. BOETTGER, 1898

Neubert, Eike, 2014, Revision of Helix LINNAEUS, 1758 in its eastern Mediterranean distribution area, and reassignment of Helix godetiana KOBELT, 1878 to Maltzanella HESSE, 1917 (Gastropoda, Pulmonata, Helicidae), Contributions to Natural History 26, pp. 1-200 : 64-67

Helix (Helix) escherichi O. BOETTGER, 1898 ( Figs 97–99 )

1898 Helix (Pomatia) escherichi O. BOETTGER, Nachrichtsblatt der deutschen Malakozoologischen Gesellschaft 30: 12 [Ak-Sehir].

Type specimens:

escherichi : holotype SMF 9840: H = 24.8; D = 25.6; PH = 19.5; PD = 13.6; PrD = 5.7; W = 4.25.

Specimens examined:

Turkey: NW Asia Minor , Eskişehir, 39.7753 30.5235, SMF 9841/3; Keuske-Kissik, 27 km from Eskişehir [not identified], SMF; Bolu, 15 krm E of Bolu at the crossroads to Yenicepınar , grassland with rocks, 40.7431 31.7393, UL91, 8.7.1988, MENK ; Bolu, rocky slope 2 km SW of Mengen , 40.9081 32.0811, VL23, 8.7.1988, MENK ; Bolu, rocks 7 km S of Eskipazar , 40.8988 32.5632, 1000 m alt., VL62 19.7.1988, MENK ; Kastamonu, 0.7 km NE Seydiler , 41.6243 33.7160, 1040 m, MENK/15 ; Ankara, vegetation at the northern shore of the YeniÇağa GÖlü, 40.7816 32.034, 8.7.1986, NMBE 512573 / 2, NMBE 505488 /2 (alk.).

Diagnosis: shell small, very large protoconch, shells usually white without spiral bands.

Description: shell of small size, thin, spherical; basic shell colour white with a brownish to greenish periostracum; protoconch large in comparison to shell, with a diameter up to 6 mm, smooth, white; teleoconch of 3 whorls with fine axial riblets, spiral bands usually missing; last whorl only slightly descending below the periphery; aperture rounded, labial callus weak, white to cream; columellar triangle small; umbilicus closed in adult shells.

Genital organs ( Fig. 98 ): penis club-shaped, epiphallus shorter than penis; flagellum extremely long, exceeding the length of epiphallus+penis fourfold; mrp attaching in a subcentral distal position on the epiphallus; internally, both papillae of equal size, penial chamber long, filled with a few longitudinal pilasters, both papillae cylindrical with a central perforation; atrial stimulator a very small, rounded knob; female system with the vaginal tube somewhat shorter than the penis, dart sac and glandulae mucosae strongly developed, the glandulae with a basic stem, multi-branched, longer than dart sac; pedunculus stem long, with a thick and short diverticulum branching off in the terminal third of the pedunculus, bursa copulatrix stem much shorter than pedunculus stem, vesicle not developed in the single specimen dissected.

Measurements of the reproductive organs of Helix escherichi [mm]: pp2 = 3.6; pp1 = 3.8; P = 7.4; Fl = 28.5; Epi = 4.5; Vag = 5.5; Ds = 8; Bc = 25.

Distribution ( Fig. 99 ): So far, this species is only recorded in a small range on the western Anatolian plateau. The classical records like Akşehir and Eskişehir are not corroborated by modern records and are far from the area around Bolu, where the species is actually known. This is probably a species that has lost larger parts of its natural range.

Remarks: Helix escherichi is unmistakable; it is in fact the smallest Helix -species known. It resembles H. pomacella in its overall shape, but has a much larger protoconch than H. pomacella , and no spiral bands. The neighbouring H. pathetica is also larger, with a few spiral bands, a smaller protoconch, and a shorter flagellum. Unfortunately, the diverticulum got lost during preparation of the only specimen available; the branching off point is indicated by an arrow.

Figures

Figs 97–98. Helix (Helix) escherichi O. BOETTGER, 1898. Fig. 97 escherichi: holotype SMF 9840, Akşehir, D = 25.6; Fig. 98 NMBE 505488 Yeniçağa Gölü, situs 34.33. — All photos Neubert, original size.

Fig. 99. Helix (Helix) escherichi O. BOETTGER, 1898. Distribution.