Sicania crassicostata (L. Pfeiffer, 1856) De Mattia & Reier & Haring, 2021

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

Sicania crassicostata (L. Pfeiffer, 1856) comb. nov.

Figs 1.F, 30.1-30.4, 31.1-31.7, 39.1-39.2

Clausilia crassicostata L. Pfeiffer 1856: 184.

Clausilia crassicostata - Schmidt 1868: 40.

Siciliaria crassicostata - Boettger 1877: 33.

Clausilia crassicostata - Westerlund 1884: 45.

Siciliaria (Siciliaria) crassicostata - Manganelli et al. 1995: 25.

Charpentieria crassicostata - Beckmann 2004: 188.

Charpentieria crassicostata - Nordsieck 2007: 54.

Siciliaria crassicostata - Welter-Schultes 2012: 339.

Charpentieria crassicostata - De Mattia 2017g.

Remarks

. The morphology of the genital organs of Sicania crassicostata comb. nov. revealed to be very stable in both of the investigated populations (Fig. 30 .1-30.4). The internal sculpturing of P is made of large longitudinal pleats that it is a common genital trait, with very few exceptions, for all the taxa belonging to Sicania.

The shell is remarkably ribbed to percostated. It shares few characters with Sicania nobilis spezialensis comb. nov. stat. nov., e.g., the (mostly) missing AUPP, both the very short (or missing) ALPP and the spiralis (mostly) not overlapping the parietalis (Fig. 39 .1-39.2).

Although Sicania eminens comb. nov. was initially introduced by Schmidt (1868: 40) as a variety of Sicania crassicostata comb. nov. due to shell similarities (and distribution proximity), the mt tree based on COI sequences reveals Sicania crassicostata comb. nov. as a distinct clade which is the sister group of Sicania nobilis s. l. (Figs 4 - 6 ). Considering the ITS2 tree and the combined tree (COI plus ITS2), the relationships among the three taxa are not well resolved. Notably, the distances between the three taxa are in the same range (~ 13%; see Table 2 ). The form of Sicania crassicostata comb. nov. from the surroundings of Tonnara di Monte Cofano is remarkably percostate, whereas the population we investigated from Mangiapane is ribbed (as stated also in Nordsieck 2013b: 9).

Specimens examined.

Italy, Sicily, Castelluzzo, cliffs W of the Tonnara di Monte Cofano , 50 m asl, 38°06'44.89"N, 12°40'34.27"E, [Lab ID 33_1, COI: MW758876 ; Lab ID 33_2, COI: MW758877 , ITS2: MW757103, MW757104, MW757105MW757131 ], W. De Mattia and J. Macor leg., 21.xii.2007. 3 dissected spm . Italy, Sicily, Custonaci, cliffs N of the Mangiapane cave , 63 m asl, 38°05'40.91"N, 12°40'10.98"E, [Lab ID 1_1, COI: MW758912 , ITS2: MW757114, MW757113 ; Lab ID 1_4, COI: MW758924 ] W. De Mattia and J. Macor leg., 21.xii.2007. 2 dissected spm .

Shell

(Figs 31 .1-31.8, 39.1-39.2).: Shell decollate; whorls markedly ribbed, in part percostate; dorsal keel weak; inferior lamella moderately high or high; anterior upper palatal plica missing, ALPP very short or mostly missing; palatal edge of clausilium plate distally not receding, palatal edge distally somewhat or not bent upwards ( Nordsieck 2013b).

Measurements

(n = 24, decollate). shell height 24.6 ± 1.2, whorl width 4.9 ± 0.1, aperture height 4.8 ± 0.3, aperture width 3.0 ± 0.1.

External morphology of the genital organs

(Figs 30 .1, 30.3). The FO is much longer than the V (FO/V range 2.8-3.0). The VD is thin along its whole course except for its proximal section that becomes wider. The FDBC is longer than the BC+SDBC (FDBC/BC+SDBC range 1.7-1.9). The BC+SDBC is club-like and longer than the V (BC+SDBC/V = 2.0), with clear distinction between the SDBC and the BC. The apex is wide and rounded. The D is much longer than the V (D/V range 3.0-3.1) and longer that the BC+SDBC (D/BC+SDBC range 1.6-1.9), thinner than the BC+SDBC, slim and with a pointed apex. The V is wide and cylindrical. The A is large. The PC is much longer than the V (P+E/V range 3.2-3.4). The PR is short and robust. The ET is missing. The E is thinner and slightly longer than the P (E/P range 1.0-1.3), gradually shrinking and turning into the VD.

Internal morphology of the genital organs

(Figs 30 .2, 30.4). The A shows few large fleshy pleats that are the direct continuation of the penial pleats. The P presents 3-6 longitudinal heavy fleshy smooth pleats that can sometimes become wrinkly and segmented. The fine structure of the wall is smooth. The V shows an irregular pattern of fine pleats. Distally, the V shows a large fleshy continuous cushion that abruptly turns proximally into a dense and irregular net-like pattern of small smooth pleats. The PP is big, short and conical with a pointed apex. The PP is big, elongated and smooth. The P-E transition presents two slightly different structures in the two dissected population. The population from Tonnara Cofano presents one ER. The PP does not originate from an ER and is connected to ELP. The epiphallar formula is: 1ER+PP(ELP). The Mangiapane population presents one ER with the PP originating from it. The ELP are not connected with the ER. The epiphallar formula is: 1ER(PP)+ELP. The E has two main longitudinal pleats, heavily segmented towards the VD, that proximally fade or can also show three smooth longitudinal pleats that almost abruptly turn into an irregular pattern of dense, small, transversely-oriented papillae.

Ecology.

Sicania crassicostata comb. nov. was collected on limestone cliffs or under rocks and boulders. According to De Mattia (2017g) Sicania crassicostata comb. nov. is considered Critically Endangered, following the IUCN criteria B1ab(i,ii,iv,v); C2a(ii) mainly due its very restricted geographic range and the severe population fragmentation.

Distribution.

This species has a very limited distribution range, restricted to the western part of Monte Cofano north of Custonaci (Tonnara di Cofano and Cornino). A (probably) introduced population is known to occur on the Island of Favignana (Trapani) ( Nordsieck 2013b), but we did not have the opportunity to check this record in the field, in order to assess whether or not the population is still extant.

Figures

Figure 1. Wagner's (1913, 1925) and Brandt's (1961) Siciliaria genital drawings A Siciliaria septemplicata, Wagner, 1913: plate 572, fig. 14 B Siciliaria grohmanniana grohmanniana, Wagner, 1925: plate 1, fig. 8 C Siciliaria calcarae calcarae, 1925: plate 3, fig. 25 D Siciliaria ferrox, Brandt, 1961: fig. 1 E overall Siciliaria / Sicania and Sicilian Mauritanica distribution F Siciliaria / Sicania and Sicilian Mauritanica distribution of taxa.

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 30. Sicania crassicostata (L. Pfeiffer, 1856), comb. nov., Monte Cofano 30.1 whole distal genital organs 30.2 internal distal part of genital organs 30.3 whole distal genital organs 30.4 internal distal part of genital organs.

Figure 31. Sicania crassicostata (L. Pfeiffer, 1856), comb. nov., Monte Cofano 31.1 shell 31.2 detail of the aperture 31.3 clausiliar plate double side 31.4 detail of the columellar side of last whorl 31.5 shell 31.6 detail of the aperture 31.7 clausiliar plate double side. Custonaci 31.8 shell.

Figure 39. Sicania crassicostata (L. Pfeiffer, 1856), comb. nov., Monte Cofano 39.1 palatal plicae 39.2 parietal lamellae. Sicania eminens (A. Schmidt, 1868), comb. nov., Custonaci, Baglio Messina 39.3 - 39.4 palatal plicae. Sicania nobilis nobilis (L. Pfeiffer, 1848), comb. nov., Castelluzzo 39.5 - 39.6 palatal plicae 39.7 parietal lamellae. Mauritanica scarificata (L. Pfeiffer, 1856), comb. nov., Marettimo 39.8 palatal plicae 39.9 parietal lamellae.