Helix (Helix) straminea Briganti, 1825

Figs 19, 20

References.

Korábek et al. 2014, 2022; Petraccioli et al. 2021.

Description.

Shell (Fig. 19) large, conical, with varying relative height; umbilicus fully covered or more rarely slit-like; individual whorls low and tightly coiled; suture deep; last whorl not expanded; aperture small and low; no umbilicus; protoconch rather large; shell surface irregular with occasional lightly coloured ribs; basic colour pale grey, usually with four well-developed dark brown bands of which the middle pair is much thicker, but bands sometimes only faint; aperture margins brown, about as dark as the bands. Animal (Fig. 20) brown including mantle margins, rarely pale brown.

Distribution and habitat.

Helix straminea occurs in the northwest of North Macedonia and in central Albania (Fig. 21); besides that, it is widely distributed in the Apennines (Petraccioli et al. 2021; Korábek et al. 2022). This species is reported here from Greece for the first time; it was found in a floodplain of a small stream north of Kalambaka (Thessaly, central Greece). Two live individuals and several empty shells were collected in a gallery forest dominated by Platanus, but with a rich herb understorey. While the mitochondrial haplotype of these specimens belongs to one of the mitochondrial lineages of H. schlaeflii, they can be identified as H. straminea based on the more conical shell with a narrower last whorl and a smaller aperture (cf. Korábek et al. 2014: fig. 4 B). A closely related H. schlaeflii haplotype was already recorded in H. straminea before in central Albania, where two other sequenced individuals from the same population had H. straminea haplotypes as expected (Korábek et al. 2022). However, that population originated from central Albania and all the H. schlaeflii haplotypes related to the haplotype from Greece obtained here also originate from central Albania. Although H. straminea (as Helix vladika (Kobelt, 1898)) was reported from an unspecified locality in the valley of Vjosa at the border between Albania and Greece (Dhora and Welter-Schultes 1996), the current record is far from the range of the species and is perhaps explainable by an introduction. However, there may exist a second population in northern Greece on the east bank of the Ioannina Lake, as documented by one convincing and two possible records posted on iNaturalist (https://www.inaturalist.org/observations/180903383, https://www.inaturalist.org/observations/189208381, https://www.inaturalist.org/observations/121853021). Furthermore, the distribution of H. straminea in the Balkan part of its range is very scattered, so it is conceivable that it extends naturally also to northern Greece.

Helix straminea was in the Balkans found in different habitats, from beech forests to shrubs. There is no clear species boundary to the closely related H. vladika in the north (northern Albania to central Serbia).