Helix (Helix) schlaeflii Mousson, 1859

Helix (Helix) schlaeflii Mousson, 1859 View in CoL

Figs 16 View Figure 16 , 17 View Figure 17

References.

Neubert 2014; Korábek et al. 2022.

Description.

Shell large, globular to conical; umbilicus sometimes slit-like but usually completely covered; protoconch large; shell surface with irregular ribs; basal colour whitish or very pale brown, more rarely the whole shell is brown; banding often reduced with upper bands 2 and 3 fused or partially fused and the lower two fuzzy and faint, but some populations have well developed, contrasting, reddish brown bands; bands with irregular whitish interruptions; aperture margins straight, only slightly reflected towards the columella; apertural lips and in particular the columellar triangle orange- or meat-brown to violet-brown, but the colouration is sometimes only faint and is missing or only weakly developed in the parietal area; mantle margins pale; animal very pale brown or grey to yellowish.

Distribution and habitat.

Common in Epirus and adjacent Western Macedonia (eastern limits uncertain, but apparently west of Kastoria, Neapoli and Grevena); occurs also on Kerkyra (Corfu). The range of the species as currently accepted extends to central Albania and up to the Galičica Mountains between the lakes Ochrid and Prespa (Fig. 18 View Figure 18 ). In Greece, it occurs in a range of habitats, from Mediterranean-type shrubby vegetation on limestones in low altitudes in the west to more temperate landscapes on sandstones in the east, but occurs also in pine forests as well as on the margins of beech forests in altitudes over 1000 m. Geophilous.

Remarks.

Differences to H. thessalica and H. borealis are described under the respective species. Helix schlaeflii differs from H. straminea in globular shape with an expanded last whorl and a larger aperture; the Greek populations often differ in a pale colouration, because H. straminea has typically more vivid colours. Helix straminea also lacks the whitish pattern on the bands characteristic for H. schlaeflii and often has a darker, brown foot.

Helix schlaeflii is not monophyletic in the mitochondrial tree (Fig. 2 View Figure 2 ). This is due to three issues. First, there are two mitochondrial clades in this species that are deeply divergent and whose mutual relationships remain unresolved. Second, the population from Krujë (central Albania, isolate SH 5 in the tree) possesses a mitochondrial lineage introgressed from Helix secernenda Rossmässler, 1847 . Third, a sample of H. straminea yielded a mitochondrial lineage typical for H. schlaeflii , apparently also due to introgression. Mitochondrial introgressions are not rare in the western-Balkan radiation of Helix ( Korábek et al. 2022) and an ancient introgression may in fact account also for the presence of two divergent lineages within H. schlaeflii . Introgressions are generally a major problem for species identification using mitochondrial data ( Funk and Omland 2003).