Gibbularia gibbula cf. sanctangeli (A. J. Wagner, 1925)

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

Gibbularia gibbula cf. sanctangeli (A. J. Wagner, 1925)

Figs 57.5, 57.6, 58.6

Distribution.

The taxon is exclusively known from the southern slopes of Monte Sant’Angelo, Gargano Peninsula (Puglia, Italy) ( Wagner 1925: 57).

Specimens examined.

Italy, Puglia, Mattinata close to Vieste , southern slopes of the Gargano Peninsula. 500 m asl, 41°45'15.61"N, 16°04'56.31"E, W. De Mattia and J. Macor leg. and det., 3 dissected spm .

External morphology of the genital organs

(Fig. 57 .5). The V is 4 × shorter than the FO. The FDBC is much longer (2 ×) than the SDBC+BC. The BC+SDBC is club-like in shape, with a more or less clear distinction between the SDBC and the BC. The D is remarkably longer than the SDBC+BC. The V is extremely short but wide in diameter. The PC is ~ 3.5 ×longer than the V. The P is spindle-like and slightly swollen. The transition between P and EP is clearly visible. The PR is short and robust. The E is almost as long as the P but slightly thinner in diameter.

Internal morphology of the genital organs

(Fig. 57 .6). The V is smooth. The P shows four to five main vast smooth pleats. These pleats are mainly longitudinally arranged but tend to become smaller and irregular to transversal along the proximal P. The pseudopapilla originates from the epiphallar thickening. The ER is connected with the ELP. The epiphallar formula is: ER(PP+ELP). The E shows four to five small longitudinal pleats that merge into two smooth ELP. They proximally fade before the VD.

Remarks.

As a shell, Gibbularia gibbula cf. sanctangeli shows reliable differences with the nominate subspecies, e.g., the bigger dimensions, the slender shape with flatter whorls, the suture without the darker band and the more prominent cervical keels. The principalis and the anterior upper palatal plicae are usually not visible from frontal view (Fig. 58 .5). We cite this population as cf. Gibbularia gibbula sanctangeli , since the typical form is known from the type locality only and this one may represent a transitional form.

Brief genital anatomical description of ten Stigmatica taxa

Stigmatica (type species Clausilia stigmatica Rossmässler, 1836 = Siciliaria (Stigmatica) stigmatica ) is currently considered as a subgenus of Charpentieria (MolluscaBase 2021) probably based on Nordsieck (2002: 29). Nordsieck’s decision (2007, 2013a) where Stigmatica is again deemed as a subgenus of Stigmatica Siciliaria wasn’t adopted. Stigmatica includes 16 taxa among species and subspecies and presents a wide distribution, including taxa from the SW Balkans (S Dalmatia, NW Greece and Ionian Islands, Montenegro and Albania) and Peninsular Italy from Tuscany southward and E Sicily ( Welter-Schultes 2012; MolluscaBase 2021), in a typical pattern of trans-Adriatic distribution as already known for, e.g., Medora ( Nordsieck 1970; 2012). In order to assess the relationships between Stigmatica and Siciliaria , four taxa of Stigmatica have undergone both molecular and genital anatomical investigations. Three additional populations were exclusively anatomically investigated (Table 10 ). In both the COI and ITS2 trees, Stigmatica forms three independent lineages, distant from Siciliaria / Sicania (Figs 4 - 6 ). In the ITS2 tree the few available clones confirmed its polyphyly, as Stigmatica pantocratoris pantocratoris from Corfu and Stigmatica stigmatica sturmii from Brindisi fall in different distant subclades. As a genital anatomical peculiarity, Stigmatica shows, even though rarely, the presence of a vestigial epiphallar flagellum, which has never been found in Siciliaria / Sicania . This structure, when present, is very difficult to be identified as extremely small and almost transparent. It was recorded in one specimen of Stigmatica incerta and Stigmatica vulcanica sigridae .

Figures

Figure 4. BI tree of based on the COI data set of Siciliaria, Sicania and related genera. BI posterior probability values (> 0.90) of major nodes are indicated.

Figure 6. BI tree of based on the concatenated COI and ITS 2 data set of Siciliaria, Sicania and related genera. Colours of Siciliaria and Sicania clades correspond to those in the distribution maps (Fig. 1 E, F). BI posterior probability values (> 0.90) of major nodes are indicated.

Figure 57. Gibbularia gibbula gibbula (Rossmaessler, 1836). Apricena, Foggia 57.1 whole distal genital organs 57.2 internal distal part of genital organs. Muggia, Trieste 57.3 whole distal genital organs 57.4 internal distal part of genital organs. Gibbularia gibbula cf. sanctangeli (A. J. Wagner, 1925), Mattinana, Vieste 57.5 whole distal genital organs 57.6 internal distal part of genital organs.

Figure 58. Gibbularia gibbula gibbula (Rossmaessler, 1836). Apricena, Foggia 58.1 shell 57.2 clausiliar plate double side. Muggia, Trieste 58.3 - 58.4 shell 58.5 detail of the aperture. Gibbularia gibbula cf. sanctangeli (A. J. Wagner, 1925), Mattinana, Vieste 58.6 shell.