80 years of research on planarians (Platyhelminthes, Tricladida) from Sardinia, Italy: an annotated checklist
Author
Stocchino, Giacinta Angela
text
Zootaxa
2018
2018-12-20
4532
4
539
552
journal article
27733
10.11646/zootaxa.4532.4.5
38d5db9a-4c71-408d-84d2-5b98fd8afa0d
1175-5326
2615649
807B317B-D883-439F-97B9-B0C0F09D9666
Dugesia sicula
Lepori, 1948
Dugesia sicula
was first reported for Sardinia on the basis of fissiparous populations, in which a certain percentage of individuals underwent a sexualization process, from 12 Sardinian localities, including 2 small nearby islets (spring and wells on the Tavolara Island Protected Area and watercourses on the S. Antioco Island) (Pala
et al
., 1995) (
Fig. 1
). After several years other fissiparous populations were found in two other watercourses, one in the northwestern Asinara Island National Park (Rio d’Auteri reservoir) (
Stocchino, 2003
) and another in southeastern Sardinia (Fiume Quirra) (M. Pala, pers. comm.) (
Fig. 1
). All Sardinian populations showed a coastal distribution with a high degree of tolerance to variations in environmental factors, especially temperature and watercourses hydrological regime e.g. temporary water (Pala
et al
., 1995; G.A. Stocchino, pers. obs.).
Dugesia sicula
has a pan-Mediterranean geographic range where it is mostly represented by fissiparous populations with only a few sexual populations being present in Mallorca,
Algeria
,
Tunisia
and
Israel
. Two mixed populations, including both sexual and fissiparous individuals, were reported from Sicily (Stocchino & Manconi 2013 and references therein). A recent reassessment of the taxonomic status of
D. biblica
Benazzi & Banchetti, 1973
from
Israel
and
Turkey
, based on morphological and molecular studies, considered this species to be a junior synonym of
D. sicula
(
Solà
et al
., 2015
)
.
As for karyology, numerous studies confirmed a diploid condition for sexual populations with a chromosome complement of 2n = 18; n = 9, and a triploid condition for fissiparous populations with a chromosome complement of 3n = 27; n = 9 + 1-5 B-chromosomes (see
Stocchino
et al
., 2012
and references therein).
Among
Dugesia
species, the haploid complement of nine chromosomes of
D. sicula
is shared with only five other species:
D. maghrebiana
Stocchino
et al
., 2009
, from North Africa;
D. arabica
Harrath & Sluys, 2013
from
Yemen
;
D. aethiopica
Stocchino
et al
., 2002
and
D. afromontana
Stocchino & Sluys, 2012
from the Afrotropical region;
D. bifida
Stocchino & Sluys, 2014
from
Madagascar
(
Stocchino
et al
., 2002
,
2004
, 2009, 2012, 2014;
Harrath
et al
., 2013
).
Although
D. sicula
is extremely widespread, a molecular analyses on many fissiparous populations from its entire distributional range revealed a remarkable pattern of low interpopulation genetic variability, which was interpreted as the result of recent anthropochore colonizations after triploidization of sexual diploid populations (
Lazaro
et al
., 2009
).