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Updated status of Anostraca, Notostraca and Spinicaudata... 15

On the basis of the description of this taxon given by COTTARELLI & MURA
(1979), the spinicaudatan collected near Messina differs from L. cortieri at
least in respect to the presence of some spineless trunk segments that the lat-
ter lacks completely. The disappearance of the only known Sicilian popula-
tion of this species and the deterioration of the sample collected and studied
by COTTARELLI & MURA (1979) make it impossible to ascertain the identity of
this Leptestheriidae.
As a result of both confirmed literature and recently found sites, the
current presence of large branchiopods was checked in forty sites. Usually,
a single species per site was found. When more species co-occur, the most
commonly observed assemblages are composed of Chirocephalus diaphanus
and Cyzicus tetracerus, and of Branchipus schaefferi and Triops cancriformis.
Unlike what has been observed in northern Tunisia, a region close to Sicily
and with a similar climate, where often two or more anostracan species
share the same habitat (Marrone, unpublished observations), the co-exis-
tence of two species belonging to the same order has been observed only
once in Sicily (Tab. 2; site 2.03).

GENERAL REMARKS

The results of the present survey show that, based on current knowl-
edge, Sicilian large branchiopod fauna is not well diversified, hosting wide-
spread taxa and lacking endemic species. All the Sicilian species with a cer-
tain taxonomical position are known also to occur in Tunisia and the Italian
mainland, with the only exception being the controversial Branchipus pasai,
which has its only European site on the Island of Lampedusa (Pelagie Archi-
pelago, AG) as well as Cyzicus tetracerus, which is still unknown on Italian
mainland but known to occur in Sardinia and Tunisia. Moreover, it seems that
the noteworthy speciation process which interested the genus Chirocephalus
on the Italian mainland did not take place in Sicily and that many steppic
taxa, common in northern Tunisia, are absent from Sicily. Very likely, the low
species richness characterising the current Sicilian large branchiopod fauna is
not the natural condition of Sicily, but the outcome of the heavy human
impact which affected, and continues to affect, Sicilian wetlands. Less than a
third of the thirteen sites mentioned in literature older than 2003 have been
found to be still existing: the remaining ones have been eliminated through
draining, filling in or, conversely, through deepening, in order to make them
permanent.
As pointed out by BELK (1998), the major risk affecting worldwide large
branchiopod populations is the destruction of their habitats. Unfortunately,