Page 5 - mamm.73.3.169

Article in press - uncorrected proof
M. Masseti: Homogenisation and the loss of biodiversity of mammals of the Mediterranean islands 173
size have been reported from the archipelago of Lavezzi,
off the southernmost coast of Corsica (Vigne et al. 1994).
Many of the extant shrews and rodents of the Medi-
terranean islands are also generally reputed to be distin-
guished from their mainland relatives by the increase in
body size (Felten and Storch 1970, Kahmann and Nie-
thammer 1971, Adler and Levins 1994, Vigne et al. 1994,
Fons et al. 1995, Amori and Masseti 1996, and many
others). Shrews and rodents regarded as large taxa are,
for example, the lesser white-toothed shrew, Crocidura
suaveolens Pallas 1811, of Corsica (Kahmann and Kah-
mann 1954, Vlasa´ k and Niethammer 1990); the Suncus
etruscus pachiurus Ku¨ ster 1835 from Sardinia (Sans-
Coma et al. 1985); the Eliomys quercinus liparensis Kah-
mann 1960, of Lipari (Kahmann 1960); the Apodemus
sylvaticus ilvanus Kahmann and Niethammer 1971, of
Elba (Kahmann and Niethammer 1971, Filippucci 1992);
and the long-tailed field mice of Formentera (A. s. fru-
mentariae Sans-Coma and Kahmann 1977), Ibiza (A. s.
eivissensis Alcover and Gosalbez 1988), the archipelago
of Hye` res (Libois and Fons 1990), and Marettimo (cf.
Krapp 1970, Alcover and Gosalbez 1988, Sara` and Casa-
mento 1995). According to some authors, such as Orsini
and Cheylan (1988) and Libois et al. (1993), the wood
mice of Corsica may also reveal a degree of dimensional
increase. The small island of Pantelleria, in the Sicilian
channel, is also inhabited by two micromammals of large
dimensions: the Pantelleria shrew, Crocidura pachyura
cossyrensis Contoli 1990 (Contoli and Amori 1986), and
the long-tailed field mouse of Pantelleria, A. sylvatucus
hermani Felten and Storch 1970 (Felten and Storch
1970). Populations of large-sized black rats have been
reported from Lipari (Cristaldi et al. 1985), and many oth-
er Mediterranean islets, as well as the Atlantic islands of
the Ac¸ ores archipelago (Portugal) (Libois et al. 1996).
Medieval populations of large black rats are known from
southern Corsica (Bonifacio) and the small islet of Lavez-
zi (Vigne et al. 1993). Another phenotypic modification is
the tendency to produce dark-coloured forms, such as
the edible dormouse, Glis glis melonii Thomas 1907, and
the garden dormouse, Eliomys quercinus sardus Barrett-
Hamilton 1901, of Corsica and Sardinia, which are, how-
ever, smaller than their continental counterparts (cf.
Amori and Masseti 1996).
It has been observed that these modifications as a
whole are not to be regarded as the effects of the so-
called ‘‘insular syndrome’’, a phenomenon that was
described several years ago as an essay of the manifes-
tations that most markedly distinguish insular micromam-
mals from their continental counterparts (cf. Libois et al.
1993, Adler and Levins 1994, Fons et al. 1995). Masseti
and Mazza (1996) attempted to verify this assumption in
the light of palaeontological evidence. In reality, the con-
stancy of patterns shown by the insular mammals of the
past attests to the fact that their endemic modifications
are the rule rather than the exception. They may be the
essential outcome of a tendency towards a redefinition
of ecological equilibria under very peculiar environmental
conditions (cf. MacArthur and Wilson 1967, Blondel and
Vigne 1993). The endemisation of island faunas is in fact
the result of a normal and repetitive reorganisation of a
few faunal entities distributed in restricted areas with lim-
ited trophic resources and in the absence of large-sized
carnivores (Masseti and Mazza 1996). This phenomenon
has been better described as the ‘‘Island Rule’’ by Foster
(1964), with mammals providing the classic case studies.
It can be seen all over the world wherever mammals
develop on ‘‘oceanic’’ islands. Moreover, according to
several authors, such as Felten and Storch (1970) and
Krapp (1984), the insular gigantism would be compre-
hensible only as a consequence of genetic drifts, in
which a role of particular importance could have been
played by the so-called ‘‘founder effect’’.
Oak jungles for endemic proboscideans
and ungulates
Fossil bones of endemic deer have been reported from
a number of Mediterranean islands, including Pianosa, in
the Tuscan archipelago, Corsica and Sardinia, Capri,
Sicily, Malta, Amorgos, Crete, Kasos, Karpathos, Tilos
and Rhodes, whereas dwarf hippopotami are known only
from Sicily, Malta, Crete and Cyprus (Sondaar and
Boekschoten 1967, Kuss 1973, 1975, Dermitzakis and
Sondaar 1978, Ambrosetti et al. 1980, Sondaar et al.
1986, Anastasakis and Dermitzakis 1990, Kotsakis 1990).
Remains of elephants have been described from the Mid-
dle-Late Pleistocene of the islands of Giglio (Tuscan
archipelago, northern Tyrrhenian Sea), Sardinia, Favigna-
na (Egadi islands), Sicily, Malta, Kythera, Euboea, Cyc-
lades (Milos, Kythnos, Seriphos, Delos, and Naxos),
Crete, Dodecanese islands (Rhodes, Tilos and Kos), Ika-
ria, Samos, Chios, Go¨ kc¸ eada (Imbros), and Cyprus
(Symeonidis and Theodorou 1982, Kotsakis 1990, Mas-
seti 1993a, Caloi et al. 1996). Recently, fossil probosci-
dean teeth have also been discovered on the islands of
Astypalaia and Kalymnos (Dodecanese, Greece) (Masseti
2002a, 2006) (Figure 6). Dwarf endemic elephants are
known amongst the Quaternary faunas of Cyprus (Bate
1903a, 1904a,b,c, Vaufrey 1929, Boekschoten and Son-
daar 1972), Rhodes and Tilos (Bachmayer et al. 1976,
1984, Symeonidis et al. 1973), Naxos, Delos and Serifos
(Johnson 1980, Symeonidis and Theodorou 1982, Davis
1987), Crete (Kuss 1970, Sondaar 1971, Symeonidis and
Theodorou 1982, Schlager 1991), Malta (Falconer 1862,
Adams 1870, Adams 1875, Vaufrey 1929), and Sicily
(Ambrosetti 1968, Ambrosetti et al. 1980, Belluomini and
Bada 1985, Bada et al. 1991). Most of these forms
appear to derive from the straight-tusked elephant, Ele-
phas antiquus Falconer and Cautley 1847, a species dis-
persed up to the Late Pleistocene in the western
Palaearctic (cf. Kurte´ n 1968, Boekschoten and Sondaar
1972, Symeonidis and Theodorou 1982, Caloi et al. 1996,
Herridge and Lister 2007) (Figure 7). The dwarf elephant,
recorded from Sardinia, is instead reputed not to belong
to the lineage of E. antiquus and is described as Mam-
muthus lamamorae Major 1883 (Azzaroli 1983, Caloi et
al. 1996).
Several explanations for the dwarfing of island mam-
mals have been suggested (Azzaroli 1971, 1977, 1982,
Sondaar 1977, 1986, Heaney 1978, Davis 1984), and
departures from the predictions of this rule are common
amongst mammals of differing body size, trophic habits