Sicania eminens (A. Schmidt, 1868) 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 eminens (A. Schmidt, 1868) comb. nov.

Figs 1.F, 32.1-32.9, 33.1-33.12, 39.3, 39.4

Clausilia crassicostata var. eminens Schmidt 1868: 40.

Clausilia crassicostata var. eminens - Westerlund 1884: 45.

Siciliaria crassicostata eminens - Alzona 1971: 92.

Charpentieria eminens - Beckmann 2004: 188.

Charpentieria eminens - Nordsieck 2007: 53.

Siciliaria crassicostata var. eminens - Welter-Schultes 2012: 339.

Siciliaria eminens - Nordsieck 2013b: 9.

Charpentieria eminens - De Mattia 2017h.

Remarks.

Sicania eminens comb. nov. inhabits a restricted range that approximately includes the surroundings of Custonaci and the S slopes of Monte Cofano in the east as far as Castellammare del Golfo in the west.

The general genital outline is stable for all the dissected populations. The internal sculpturing of the penis reveals a basic pattern of one to four longitudinal pleats. The remaining main genital internal parts (penial pseudopapilla, epiphallus and atrium) show good stability despite slight variations, which will be described below. Only the internal wall of the vagina could be either smooth or with a strong sculpturing.

The shell is remarkably ribbed although the number of the ribs (density) progressively decreases along a geographical S-N axis, whereby simultaneously the thickness of the ribs increases. Southern populations, e.g., from Dolina Buffara and Baglio Messina, present a dense ribbing (with an average of 70 ribs along the first whorl) whereby the northernmost populations from the environs of Mangiapane Caves and Scurati show much less rib density (with an average of 32 ribs along the first whorl). The northern populations are found a few hundred meters from the southernmost population of Sicania crassicostata comb. nov. and could be, by inexperienced eyes, easily confused with it. Probably this is the reason why the taxon was for long time considered as a subspecies of Sicania crassicostata comb. nov. (Alzona, 1971: 92). Nevertheless, Sicania eminens comb. nov. can be distinguished by the markedly pyriform shape of its shell and the presence of a strong anterior upper palatal plica and the ALPP, both of them clearly visible from outside of the shell’s aperture and missing in Sicania crassicostata comb. nov. (Figs 31 .1-31.7, 39.1, 39.2).

Sicania eminens comb. nov. is monophyletic in both the COI and in the ITS2 tree (both well supported). The ITS2 sequences were almost identical (Fig. 5 ). The distribution of the samples within the subclade, in spite of their low number, approximately reflects the S-N gradient in the rib density of the shells. The upper part includes the southern high-rib-density populations of Dolina Buffara and Baglio Messina, whereas the lower part includes the low-rib-density populations of Custonaci and Contrada Scurati. The results of the molecular genetic analysis, the morphology of the genital organs, conchological and biogeographic investigations confirm the status of Sicania eminens comb. nov. as a valid species, clearly distinguished from Sicania crassicostata comb. nov.

Specimens examined.

Italy, Sicily, Custonaci, contrada Scurati, crossing with Strada Procinciale 19, 60 m asl, 38°4'55.97"N, 12°40'9.91"E, [Lab ID 51_1, COI: MW758896 , ITS2 MW757072 ; Lab ID 51_2, COI: MW758897 ], W. De Mattia and J. Macor leg., 12.iv.2017. 2 dissected specimens . Italy, Sicily, Custonaci, contrada Scurati , 60 m asl, 38°05'18.10"N, 12°40'17.18"E, [Lab ID 52_1, COI: MW758898 ; Lab ID 52_2, COI: MW758899 , ITS2 MW757071, MW757085, MW757086 ], W. De Mattia and J. Macor leg., 12.iv.2017. 2 dissected spm . Italy, Sicily, Custonaci, contrada Scurati, crossing with Strada Provinciale 18, 65 m asl, 38°4'56.04"N, 12°40'9.86"E, W. De Mattia and J. Macor leg., 12.iv.2017. 2 dissected spm . Italy, Sicily, Custonaci, contrada Scurati , limestone cliffs S of the village, 60 m asl, 38°06'44.89"N, 12°40'34.27"E, W. De Mattia and J. Macor leg., 12.iv.2017. 2 dissected spm . Italy, Sicily, Custonaci, Buffara, NE side of the hollow, 150 m asl, 38°04'0.52"N, 12°41'1.34"E, [Lab ID 49_1, COI: MW758892 ; Lab ID 49_2, COI: MW758893 ], W. De Mattia and J. Macor leg., 12.iv.2017. 2 dissected spm . Italy, Sicily, Custonaci, Baglio Messina , 340 m asl, 38°04'6.38"N, 12°41'48.68"E, [Lab ID 50_1, COI: MW758894 , ITS2 MW757073, MW757074, MW757075, MW757076 ; Lab ID 50_2, COI: MW758895 ], W. De Mattia and J. Macor leg., 12.iv.2017. 2 dissected spm .

Shell

(Figs 33 .1-33.12, 39.3, 39.4). shell decollate; whorls ribbed; dorsal keel weak or missing; inferior lamella mostly high; anterior upper palatal plica strong, mostly separated from upper palatal plica, ALPP tending to be shortened but visible; palatal edge of clausilium plate distally not receding, palatal edge distally somewhat or not bent upwards ( Nordsieck 2013b).

Measurements

(n = 45, decollate): shell height 20.1 ± 0.7, whorl width 4.7 ± 0.3, aperture height 4.7 ± 0.4, aperture width 3.1 ± 0.1.

External morphology of the genital organs

(Figs 32 .1, 32.4, 32.6, 32.8). The FO is remarkably longer than the V (FO/V range 4.1-4.7). The VD is thin along its whole course. The FDBC is longer than the BC+SDBC (FDBC/BC+SDBC range 1.6-1.9). The BC+SDBC is club-like and longer than the V (BC+SDBC/V range 2.1-2.5), with distinction between the SDBC and the BC. The apex is wide and round. The D is much longer than the V (D/V range 4.4-4.9) and longer that the BC+SDBC (D/BC+SDBC range 2.4-2.7), thinner than the BC+SDBC, slim and with a pointed apex. The V is short, wide and cylindrical. The A is very large. The PC is much longer than the V (P+E/V range 3.7-4.2). The PR is short and robust. The ET is not present in all the dissected samples. The E is thinner and shorter than the P (E/P range 0.8-0.9), almost abruptly shrinking and turning into the VD.

Internal morphology of the genital organs

(Figs 32 .2, 32.3, 32.5, 32.7, 32.9). The A shows few large fleshy pleats that are the direct continuation of the penial pleats. The P presents 1-4 longitudinal fleshy pleats. These pleats can be totally smooth (Contrada Scurati), only one or few of them are segmented (metameric) (Contrada Scurati, Dolina Buffara) or the only pleat is proximally segmented and distally irregular (Baglio Messina). The fine structure of the wall is smooth. The PP is always very small and rounded. It is smooth but in Baglio Messina where it is remarkably wrinkly. The P-E transition presents three slightly different structures in the dissected populations. The samples from Dolina Buffara present one ER with the PP and ELP originating from the ER. Its epiphallar formula is: 1ER(PP+ELP). The samples from Scurati show a common structure, namely a first distal ER where the PP originates and the ELP originate from the second proximal ER. The epiphallar formula is: 1ER(PP)+2ER(ELP). The population from Baglio Messina present a slight difference with a first distal ER, whereas the PP and the ELP originate from the second proximal ER. The epiphallar formula is: 1ER+2ER(PP+ELP). The E shows two main longitudinal pleats that can be either smooth or fringed. These two pleats distally originate from a set of smaller irregular pleats. The V can be either completely smooth or with a set of irregular smooth pleats.

Ecology.

Sicania eminens comb. nov. inhabits limestone cliffs and boulders, hiding in rock cracks and crevices. It is also found climbing on tree barks and decaying woods (Custonaci, Baglio Messina). This taxon has never been found syntopic with other Sicania or Siciliaria taxa. Along its eastern distributional range, it is sympatric with Siciliaria calcarae calcarae . According to De Mattia (2017h) Sicania eminens comb. nov. is considered Endangered following the IUCN criteria B1ab(iv,v)+2ab(iv,v). Approximately 20% of its distribution range (mainly in the southern part) is currently under a heavy quarrying activity. This results in a complete habitat destruction. Only a very small part of its distributional range falls under a protected area: Riserva Naturale Orientata di Monte Cofano, between Monte Cofano and Monte Palatimone. The subpopulations are fragmented and localised over very small areas. This species is assessed as Endangered since it has a very restricted geographic range, it occurs at less than five locations and there is a continuing decline in the quality of the habitat and in the number of mature individuals due to extended periods of drought in the summer. In addition, this species is an extremely sought-after item for shell collectors and traders ( De Mattia 2017h).

Distribution.

The distribution range of Sicania eminens comb. nov. includes the southern slopes of Monte Cofano and Monte Palatimone in the north and, in the south, the line from Monte Sparagio-Castellammare del Golfo (east) and Monte Buffara (west). Nordsieck (2013b) includes the surroundings of Calatafimi and Monte Bonifato near Alcamo but recent field research failed to find this taxon in these localities.

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

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 32. Sicania eminens (A. Schmidt, 1868), comb. nov., Custonaci, Baglio Messina 32.1 whole distal genital organs 32.2 internal distal part of genital organs 32.3 detail of the pseudopapilla. Dolina Buffara 32.4 whole distal genital organs 32.5 internal distal part of genital organs. Contrada Scurati, Custonaci 32.6 whole distal genital organs 32.7 internal distal part of genital organs. Contrada Scurati toward Mangiapane 32.8 whole distal genital organs 32.9 internal distal part of genital organs.

Figure 33. Sicania eminens (A. Schmidt, 1868), comb. nov., Custonaci, Baglio Messina 33.1 shell. 33.2 detail of the aperture 33.3 clausiliar plate double side. Dolina Buffara 33.4 shell 33.5 detail of the aperture 33.6 clausiliar plate double side. Contrada Scurati, Custonaci 33.7 shell 33.8 detail of the aperture 33.9 clausiliar plate double side. Contrada Scurati toward Mangiapane 33.10 shell 33.11 detail of the aperture 33.12 clausiliar plate double side.