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S. riberothi Brandt 1961

Fig. 7

Diagnosis: Shell decollated; whorls ribbed; dorsal keel prominent; inferior lamella high; anterior upper palatal plica
present, mostly separated from upper palatal plica; palatal edge of clausilium plate distally not receding, palatal edge
distally not bent up.

Distribution: Unknown (Trapani province?) (see chapter 3.).

2. Interspecies hybridization

The forms of Siciliaria (S.) assumed to be hybrid ones, which are enumerated in the following, are forms of well­defined
species restricted to certain localities or regions differing from the nominotypical forms by showing characters of
another species. This other species is clearly different from that species and is distributed in the same region. The
assumed hybrid forms occur in the neighbourhood of or are even surrounded by populations of the nominotypical form
of the species to which they belong. In all probability, they are the products of a limited gene flow from the other
species restricted to a limited locality or region. This may be a similar case of interspecies hybridization as, e. g., in the
genus Delima in central Dalmatia (Nordsieck 2007: chapter VI, 99­101).
The assumed hybrid forms are the following:
1. S. grohmanniana, Priola form (fig. 8), with characters of S. septemplicata, occurring in the environs of Palermo,
where both species are distributed.
2. S. septemplicata, Parco form, with characters of S. calcarae, from a locality near Palermo in a region, where both
species have been traced in localities nearby.
3. S. septemplicata alcamoensis (fig. 9) = S. s. hemmeni, with characters of S. tiberii, the latter occurring near Cinisi in
a region, where both species are distributed. The locality Alcamo for S. s. alcamoensis is probably wrong, also because
neither S. septemplicata nor S. tiberii have been found in that region. The shell from Alcamo figured under the name S.
s. alcamoensis in the Internet forum Natura Mediterraneo (XII.2009) belongs to S. calcarae.
4. S. calcarae, Sagana form, with characters of S. septemplicata, from a locality near Montelepre in a region, where
both species have been traced in localities nearby.
5. S. calcarae belliemii from Monte Belliemi, with the ribbing of S. tiberii, which occurs in the Monte della Fiera nearby.
6. S. tiberii from Monte della Scala (fig. 10), with characters of S. calcarae.
7. S. tiberii scalettensis, with characters of S. septemplicata, from a locality near Cinisi where both species are
distributed.
8. S. leucophryna, Sferracavallo form, with characters of S. calcarae, from Sferracavallo where both species have been
found.
9. S. crassicostata with normally ribbed shell from near Monte Cofano and part of Monte Cofano, ribbing like S.
eminens.

3. The riberothi problem

The taxon which has been described by Brandt (1961: 8) as S. leucophryne riberothi is a special problem within the
systematics of Siciliaria (S.). The locality of the type form „valley north of Ribera“ given by Monterosato, who provided
it as Clausilia riberothi, is probably wrong. The species cannot be found in the environs of Ribera (Agrigento province)
(Beckmann 2004: 188); besides, this locality is outside the range of Siciliaria (S.). Another form (fig. 7), also coming
from Monterosato and named C. remota (this name, however, has been used by him also for the northern form of S.
tiberii, Brandt 1961: 8), is said to come from the mountains „della Terrazza“ (or „Torrazza“) in the Trapani province
(two samples, already mentioned by Beckmann: 188). This locality, within the range of Siciliaria (S.), could not be
traced until now. In contrast to all other Siciliaria (S.) species, S. riberothi does not appear in the Internet forum Natura
Mediterraneo.
S. riberothi differs from S. leucophryna by the prominent dorsal keel, which is like that of the northern form of S.
tiberii, and from S. leucophryna and S. tiberii by the clausilium plate (fig. 7), which is like that of the nobilis subgroup
(and S. ferrox). Therefore, it is provisionally regarded as an independent species.
It is a task for malacologists in Sicily to rediscover this questionable species with unknown origin.