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5.5 New records of two alien molluscan species from Astypalaia Island in the southern Aegean Sea

A. Angelidis

During a visit to Astypalaia Island in July 2016, two
hitherto unreported bivalves. Namely. Malleus regula
(Forsskål in Niebuhr, 1775) and Fulvia fragilis (Forsskål
in Niebuhr, 1775), were discovered.
Malleus regula is an epibyssal pteriid with high
tongue shape, widely distributed in the tropical Indo-Pa-
cific region including the Persian Gulf and the Red Sea. It
was recorded in the Suez Canal as early as 1905, while the
first Mediterranean record is from Israel and Lebanon in
1929 (Pallary, 1938). Successive records from the coasts
of almost all the east Mediterranean countries, from Lybia
to Turkey, attest successful establishment (Zenetos et al.,
2004). The first Greek record is from Simi, Greece (Gian-
nuzzi-Savelli et al., 2001).
Five live specimens of M. regula were collected at
Kounoupoi islet (36.531408° N, 26.469313° E) at a depth
of 2 m, under stones (Fig. 21). All specimens were juve-
niles ranging from 15 mm to 17 mm in size. The specimens
had fragile semitransparent shells, whitish in colour, and a
nacreous interior. They were attached by their byssuses to
the stones forming a small group. The age and arrange-
ment of the examined material suggests the beginning of Fig. 21: Live Juvenile specimens of M. regula from Kounou-
establishment. Lack of harbor, fishing refuges and fisher- poi isl., Astypalaia.
ies in vicinity, indicates transportation via natural ways
following the relative pattern of Lessepsian migration. main island’s harbour and a fishery harbour are located
The bivalve Fulvia fragilis is native in the Western close to the gulf’s opening. Vathi bay presents estuarine
Indian Ocean, Persian Gulf and Red Sea. It was first features like the gulf of Thessaloniki and the gulf of Ka-
recorded in the Mediterranean in 1955 as Papyridea pa-
pyracea from Egypt (Moazzo, 1939). Successive records lloni in Lesvos where F. fragilis is also present. It has
from southern Turkey, Tunisia, Malta, Italy and Spain muddy bottom with Zostera sp. and it is also used as a
verify its establishment in the Mediterranean (Zenetos secondary harbor. Three specimens were hand-collected
et al., 2004). The first Greek record is from Saronicos in shallow water by snorkeling. Two of them were living
Gulf, (Vardala-Theodorou, 1999) and successively from (Fig. 22) and one was freshly dead. The disposition age
Thermaicos Gulf (Angelidis, 2012), where it is well- and number of examined specimens suggests that the spe-
established today. cies is established in the area. Although shipping cannot
The precise locality of this new F. fragilis occurrence be excluded as a potential vector of introduction in the
is in Astypalaia (36.619077° N, 26.393020° E), in Vathi area, transportation via natural ways (unaided dispersal)
bay which is a small bay in the north of the main island following the pattern of Lessepsian migration seems to be
with a very narrow channel-like opening facing SW. The the most probable way of introduction.

Fig. 22: Live specimens of F. fragilis from Vathi Bay, Astypalaia. Sizes 30-40 mm.

Medit. Mar. Sci., 18/1, 2017, 179-201 195