Orcula (Hausdorfia) zilchi Urbanski 1960

Pall-Gergely, Barna, Deli, Tamas, Irikov, Atanas & Harl, Josef, 2013, Subgeneric division of the genus Orcula Held 1837 with remarks on Romanian orculid data (Gastropoda, Pulmonata, Orculidae), ZooKeys 301, pp. 25-49 : 34-37

Orcula (Hausdorfia) zilchi Urbanski 1960

Orcula zilchi Urbański, J., Bulletin de la Société des Amis des Sciences et des Lettres de Poznan ( Série D) 1: 57. [ ‘’ Am rechten Ufer des Ropotamo, etwa 3 km vor seiner Mündung (etwa 30 km südlich von Burgas) ’’]. (1960)

Orcula zilchi , - Damjanov and Likharev, Fauna Bulgarica, Gastropoda terrestria, vol. IV: 115. (1975)

Orcula (?) zilchi, - Hausdorf, Archiv für Molluskenkunde125 (1/2): 14, Plate 1, fig. 1. [ ‘’ Westanatolien: V. Kütahya, Safa 2 km R Domaniç’’]. (1996)

Orcula zilchi , - Páll-Gergely, Zoology in the Middle East, 50: 91. (2010)

Orcula zilchi , Harl et al. - Archiv für Molluskenkunde, 140 (2): 186-187, Plate 4, fig. F, G. (2011)

Orcula zilchi , - Welter-Schultes, European non-marine molluscs:146. (2012)

Material.

Bulgaria, Strandzha Mts., Kondolovo village, 42°6.150'N, 27°39.896'E, leg. Irikov, A., 28.04.2012. (anatomically examined); Bulgaria, Silkosiya Reserve, near Kosti Village, 23.06.2001, leg., А. Irikov; Turkey, Vil. Bolu, Abant Gölü N, 1030 m, 40°38.756'N, 31°21.531'E, leg. Páll-Gergely, B., 17.05.2006.; Turkey, Vil. Bursa, between Bozüyük and İnegöl, by the ‘’ Mezit 7 ’’ bridge, limestone rocks and beach forest next to the road, 580 m, 39°55.724'N, 29°43.939'E, leg. Páll-Gergely, B., 30.09.2007; Bulgaria, floating debris 6 km N of Malko Tarnovo, 210 m, UTM NG 45, 42°5.028'N, 27°25.698'E, leg. Dedov & Subai 8.5.2008, SP 22168/2 (juv.)

Description of the genitalia.

Two specimens were dissected. Penis cylindrical, relatively long; retractor muscle short, attaches on the proximal portion; penial caecum very long, with a thickened base and a cylindrical distal portion; an additional canal (?) connects the proximal end of the epiphallus with the penial caecum; epiphallus long, with a thickened distal part; the separation between the vas deferens and epiphallus is distinct; vas deferens relatively thick. Vagina cylindrical and relatively short; bursa copulatrix extremely long with a pointed end.

A developing egg covered with small calcareous crystals was found in the uterus of the figured specimen. In the other specimen, an elongated, simple bursa copulatrix was found with a slightly thickened apical part.

Distribution.

South-Eastern Bulgaria and North-Western Turkey.

Ecology.

The type series (12 shells) of Orcula zilchi was collected by Urbański on the floodplain of the Ropotamo River in leaf litter and under decaying wood. It was found in association with Sphyradium doliolum ( Bruguière 1792), Oxychilus deilus rumelicus Hesse, Laciniaria plicata (Draparnaud), Bulgarica denticulata thessalonica ( Rossmässler), Euxina persica paulhessei (Lindholm), Euxina circumdata (L. Pfeiffer), Cochlodina laminata (Montagu). Atanas Irikov visited the type locality (very humid forest with rocks along the river) on two occasions, with collection time totalling 6-8 hours. Besides Orcula zilchi he collected all other species previously reported from the Ropotamo area.

We were able to find Orcula zilchi only in deciduous forests. In Bulgaria (near Kondolovo village), living specimens were collected in an oriental beech ( Fagus orientalis ) forest in shady and moist microhabitats between the leaf litter and soil. These conditions were very similar to the Abant Gölü locality (Turkey). The other Turkish locality (between Bozüyük and İnegöl) was slightly different, with a deciduous forest at the base of a large limestone rock, on a slope covered with smaller stones and larger rocks.

The species is very rare wherever it has been encountered yet, especially in Turkey. On two occasions, in 2007 and 2010, Barna Páll-Gergely spent about 4-5 hours at the locality in vil. Bursa, but found only one specimen in 2007. The other locality (Vil. Bolu) was visited in 2005 and 2006 for similar lengths of time and only one specimen was found in 2006. Atanas Irikov collected 9 living specimens and about 10 empty shells in an hour near Kondolovo in Bulgaria.

Conservation status.

Listed as Vulnerable (V) under IUCN criteria ( Pall-Gergely 2011b). Deforestation and disturbance of the forests are the main threat to this species.

Remarks.

Two of four living specimens had beetle (possibly drilid beetle) larvae in the body whorl.

The dissected specimens were collected about 23 km south-southwest of the type locality. The Strandzha Mountains (incl. the collecting site) belongs to the drainage of the Ropotamo River. It is reasonable to suppose that Urbański’s population was "washed down" from somewhere in the Strandzha Mts. and settled a temporary subpopulation in the Ropotamo floodplain. This might be a reasonable explanation why A. Irikov could not find this species in the type locality.