Iberus rhodopeplus rhodopeplus Aguilar Amat, 1925

Iberus rhodopeplus rhodopeplus Aguilar Amat, 1925

( Figs 9–11 View FIG View FIG View FIG )

Iberus alonensis rhodopeplus d’Aguilar Amat, 1925: 266 .

Type material. Fig. 9 View FIG shows the syntype of I. rhodopeplus rhodopeplus which represents the only reference shell available from the Aguilar Amat´s collection, deposited in the Museu de Ciències Naturals de Barcelona ( Spain) with register number MZB 89-2580 View Materials .

Type locality. Since Aguilar Amat [1925] did not designate a holotype, the type locality must be assigned to the only known syntype assigned by the author to ‘ El Muruche’, Jaén ( Spain). It should be noted that most likely, the type locality stated by the author is actually Mount Moroche , located in the town of Pegalajar, Jaén ( Spain). For comparative purposes, a specimen recently sampled by the authors at Aguilar Amat´s historic locality is shown in Fig. 9 View FIG .

Etymology. Aguilar Amat [1925] suggested the term ‘rhodopeplus’ as subspecific epithet to describe a local race characterised by “ showing a mantle of a beautiful salmon colour”.

Description. Live specimens of I. rhodopeplus rhodopeplus typically show a bright yellow body and a pink or salmon-coloured mantle. This is not the only case of pink mantle within the genus Iberus [ Lietor et al., 2024c]. By contrast, the yellow body can be considered as distinctive for this taxon. Major diameter of I. rhodopeplus rhodopeplus shell ranges from 22 to 48 mm.

The typical shell of I. rhodopeplus rhodopeplus is globose, occasionally compressed, unkeeled and not umbilicated. It has an acute apex and 4.5–5 whorls of regular growth. The suture is simple and visible in all whorls. Protoconch has 1–1.5 whorls and is smooth, exhibiting a uniform light to dark brown colour. The shell surface is radially (transversally) striated, except in the smooth protoconch. The radial striae show an irregular spatial pattern.Additionally, there is a spiral (longitudinal) striation of variable intensity depending on populations, resulting in a marked reticulation. Shell aperture is large, from oval to semilunar, wider than high (equivalent to approximately half the total width of the shell). The peristome is white, solid and reflected, with the exception of some populations in which it may be slightly cutting. The umbilicus area exhibits a bright white dilated columellar expansion that becomes a callus with variable intensity and extension depending on the populations. The colour of the shell in the first three whorls (excluding the protoconch) may vary from off-white to dark brown. Last whorl of the spire shows five dark brown bands (except for populations with no bands); the lower two are wider, more intensely marked and located at a greater distance from each other than the upper three. They can be continuous, but sometimes they are interrupted by marmorations that provide an intermittent band pattern. The bands never reach the edge of the lip. The other three bands, somewhat narrower, are placed in the penultimate and antepenultimate whorls of the spiral, being less marked and interrupted by weaker marmorations in some populations.The distance that separates them from the two lower bands may be 2–4 times the space among them.

Series of conchological variability of I. rhodopeplus rhodopeplus can be checked in Fig. 10 View FIG .

Habitat. I. rhodopeplus rhodopeplus occurs at an altitude range between 9 m and 1,345 m above sea level (a.s.l.). It is one of the most ubiquitous snails within the genus Iberus . Although its typical habitat consists of limestone walls and calcareous rock formations inside Mediterranean shrublands or occasionally pine and holm oak forests, it may also occur on siliceous lithology (quartzite and slate) ( Fig. 11 View FIG ). When limestone cracks and cavities are not available, snails take refuge deep under bushes and on the lower side of medium to large sized rocks.

Remarks. I. rhodopeplus rhodopeplus is one of the taxa that molecular analysis has demonstrated to be part of the traditional I. alonensis morphospecies, being attributed to the I. alonensis populations throughout the western part of Andalusia (southern Spain). Despite the conchological similarity between I. rhodopeplus rhodopeplus and I. alonensis s. str., both taxa constitute well-differentiated sister lineages, with a genetic distance of ~13% for COI and ~8% for 16S rRNA ( Table 2).

Some morphological features of I. rhodopeplus rhodopeplus are sufficiently distinctive to allow it to be differentiated from the rest of the large-sized Iberus from southern Spain. In addition to the abovementioned striking colours of the mantle and the body, it can be added a significantly larger size than I. carthaginiensis ( Rossmässler, 1853) , I. globulosus C.R. Boettger, 1913 . I. alonensis -like 01 (sensu Elejalde et al., 2008a) and I. mariae Cobos, 1979 (unpublished data).Albeit I. campesinus (L. Pfeiffer, 1846) and I. gualtieranus , the two remaining taxa of the I. rhodopeplus rhodopeplus clade ( Fig. 3 View FIG ) can match or even exceed it in size, the highly contrasted morphologies of all of them prevent confusion.