Charpentieria itala variscoi (Pini, 1883)

De Mattia, Willy, Reier, Susanne & Haring, Elisabeth, 2021, Morphological investigation of genital organs and first insights into the phylogeny of the genus Siciliaria Vest, 1867 as a basis for a taxonomic revision (Mollusca, Gastropoda, Clausiliidae), ZooKeys 1077, pp. 1-175 : 1

Charpentieria itala variscoi (Pini, 1883)

Figs 49.3, 49.4, 50.6

Distribution.

This taxon is known only from the Val Brembana and Val Taleggio (Bergamo, Lombardia, Italy) ( Nordsieck 1963b).

Specimens examined.

Italy, Lombardia, Bergamo, Lavina, Val Taleggio. 650 m asl, 45°53'11.73"N, 09°33'55.46"E, W. De Mattia and J. Macor leg. and det., 2 dissected spm .

External morphology of the genital organs

(Fig. 49 .3). The V is slightly shorter than the FO. The FDBC is as long as the SDBC+BC. The BC+SDBC is club-like in shape with clear distinction between the SDBC and the BC. The D is longer than the SDBC+BC. The V is short and slightly swollen. The PC is ~ 3 × as long as the V. The P is fusiform. The transition between P and EP is not clearly visible. The PR is long and thin. The E is slightly shorter than the P and thinner in diameter.

Internal morphology of the genital organs

(Fig. 49 .4). The A and the V are smooth. The P is distally smooth, with transversal irregular weak pleats along its proximal part. The PP is folded and very elongated. It occupies the whole penial volume. The PP originates from the ER that is connected with the ELP by means of few Clausilia minor longitudinal pleats. The epiphallar formula is: PP(ER+ELP). The E shows two moderately fringed ELP. They proximally fade before the VD.

Brief genital anatomical description of Charpentieria stenzii subspecific taxa

Charpentieria stenzii is present along the Eastern Alps, from the Val di Non in Trentino and Pre-Alps of Veneto in the West to the Alpi Giulie in the East ( Zallot 2001; Welter-Schultes 2012). Currently nine subspecific taxa are considered valid ( Zallot 2001: 137-138; MolluscaBase 2021). Charpentieria stenzii shows a remarkable variability as regards the shell features. This is well depicted and described in Zallot (2001: 143-155). As for C. itala the subspecies were traditionally based on shell morphological characters, e.g., the sculpturing of the shell surface (smooth, striated to ribbed) or the development and variability of the internal plicae and lamellae. The shell is almost smooth or weakly striated to striated or frankly ribbed (as in C. stenzii letochana ). The suture is always remarkably whitish. Compared to C. dyodon , C. itala and C. ornata , the species, presents a reduction of the buccal armature, with both, columellaris and parietalis generally small to almost absent. The lunella is usually weak to almost undetectable ( Zallot 2001).

Eight of nine subspecies of C. stenzii were anatomically investigated (Table 8 ). A new anatomical feature, namely the hemipapilla, was discovered and revealed to be typical and exclusive of this species. The hemipapilla consists of an uninterrupted, circular and fleshy elevated ring that almost entirely obliterates the lumen along the penis and epiphallus transition area, slightly distally to the PR. The base of the pseudopapilla is fused with almost the entire ring, making it difficult to distinguish it from a real penial papilla. The sperm channel is anyway present, it is not just a narrow section as in the epiphallar ring of Sicania / Siciliaria or the rooted pseudopapilla. Its outlet is found at the base of the pseudopapilla (Figs 51 - 54 ). The pseudopapilla is channel-less and filled-up of spongy tissue. The inner atrial pad depicted and deemed by Nordsieck (1963b) as a characteristic of the species, in our genital anatomical investigations was found only in C. stenzii letochana . The other subspecies of C. stenzii showed a variable inner sculpturing of the atrium, from irregular smooth pleats (as C. stenzii faueri ) to almost smooth (as C. stenzii westerlundi ) with different degrees of complexity in between.

Figures

Figure 49. Charpentieria itala triumplinae Nardi, 2011, Lavenone, Brescia 49.1 whole distal genital organs 49.2 internal distal part of genital organs. Charpentieria itala variscoi (Pini, 1883), Val Taleggio, Bergamo 49.3 whole distal genital organs 49.4 internal distal part of genital organs.

Figure 51. Charpentieria stenzii stenzii (Rossmaessler, 1836), San Romedio, Trento 51.1 whole distal genital organs 51.2 internal distal part of genital organs 51.3 cross section of the epiphallus. Charpentieria stenzii butoti (Bank, 1987), Fai della Paganella 51.4 whole distal genital organs 51.5. internal distal part of genital organs 51.6 detail of the hemipapilla: uncut 51.7 detail of the hemipapilla: cut funnel 51.8 cross section of the epiphallus.

Figure 54. Charpentieria stenzii letochana (Gredler, 1874), Val Fonda, Belluno 54.1 whole distal genital organs 54.2 internal distal part of genital organs 54.3 detail of the hemipapilla: uncut 54.4 detail of the hemipapilla: cut funnel 54.5 cross section of the pseudopapilla 54.6 cross section of the epiphallus.