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Zoomorphology

beach debris (Colombini et al. 1994). In view of their (subspecies, ‘‘races,’’ ‘‘nationes,’’ cf. Canzoneri 1968), or
limited dispersal capacity and their high habitat specificity, at least described as such (Canzoneri 1968). One such
darkling beetles also exhibit a noteworthy degree of example is the subspecies P. bimaculata marcuzzii Aliquo `
endemicity, as reported in several studies, including the 1993, which was described for the Aeolian Islands (Fig. 1),
ones by Contreras-Diaz et al. (2003) for tenebrionid species with its locus typicus located on the island of Vulcano
from the Canary Islands and by Fattorini and Leo (2000a) (Aliquo ` 1993). The P. bimaculata populations from the
for the Aegean Islands. Aegadian Islands are also considered different from the
The tenebrionid beetles Phaleria bimaculata and P. nominal subspecies by Canzoneri (1970), but they have not
acuminata belong to a speciose and a widely distributed been formally described as such.
psammophilous genus; P. bimaculata (Linnaeus, 1767) has The results of a geometric preliminary morphometric
a wide Mediterranean distribution (Lo ¨bl and Smetana analysis of different P. bimaculata populations from the
2008) with morphologically distinct populations that have Maltese and Sicilian archipelagos, reported in Deidun et al.
been often described as new taxa of doubtful taxonomical (2011), confirmed the high degree of inter-populations
meaning (e.g., Canzoneri 1968; Marcuzzi 1996; de Jong morphological variability within P. bimaculata from such a
2010). The congener P. acuminata Ku ¨ster, 1852 is dis- geographical region. The results proved to be compatible
tributed along the sandy coastlines of the Mediterranean with the possible subspecific taxonomic status of the
(Lo ¨bl and Smetana 2008), Bulgaria, and the Black Sea Aeolian P. bimaculata populations (i.e., P. bimaculata
(Dajoz 1984). Though the two species show overlapping marcuzzii). In light of these results, Deidun et al. (2011)
ranges, they have not been compared using genetic and recommended the inclusion of a higher number of Phaleria
morphometric methods to date. Their genetic diversity is populations in the geometric morphometric analyses, and
nearly unknown, and studies to identify molecular diag- the implementation of molecular techniques to test and
nostic characters have never been performed. Unfortu- corroborate the results of both traditional morphology and
nately, no phylogeny of the genus Phaleria is currently geometric morphometry analyses. Following these guide-
available, and there is thus no evidence supporting the lines, the primary aims of this paper are (1) to describe the
sister-species relationship between P. acuminata and morphological and molecular diversity of the central
P. bimaculata. Mediterranean populations of two widespread Phaleria
The two studied species (P. acuminata and P. bimacu- species and (2) to compare the accuracy and consistency of
lata) have been recorded in large numbers from Maltese different identification techniques, i.e., traditional mor-
(Deidun et al. 2007, 2009) and Sicilian beaches (Canzoneri phology, molecular identification, and geometric mor-
1968; Aliquo ` and Leo 1997–1998; Fattorini and Leo phometry. Finally, the study also aims (3) to gauge the
2000b; Deidun et al. 2011), while a third species, P. rev- putative degree of compartmentalization along close bea-
eilleri Mulsant and Rey 1858, which is sometimes reported ches through the characterization of the within-species and
to occur in Sicily (e.g., Canzoneri 1968; but see also Ali- between-species variation of P. bimaculata and P. acumi-
quo ` and Soldati 2010), was not recorded in the frame of our nata sampled over different spatial scales.
surveys. P. bimaculata and P. acuminata have been rarely
recorded in syntopy (e.g., Mifsud and Scupola 1998; Dei-
dun et al. 2010), and they demonstrate slightly different Materials and methods
eco-ethological characteristics. They seem to occupy dif-
ferent beach zones (Deidun et al. 2010) and have different Sampling
grain-size preferences: P. acuminata shows a predilection
for fine-sand beaches, and P. bimaculata prefers coarser A total of 25 Phaleria spp. populations from sandy
sand (in some extreme cases, P. bimaculata is also found beaches on different central Mediterranean archipelagos
on cobble beaches, e.g., Canzoneri 1968; Gardini 1975; (Maltese, Pelagian, Aegadian, and Aeolian ones) and on
Minelli et al. 2002). the Sicilian mainland were sampled once, over the
From a taxonomic perspective, the P. acuminata popu- March–October 2010 period (Fig. 1). The full list of
lations from the central Mediterranean area show a scarce sampled sandy beaches is given in Table 1, while Fig. 1
differentiation, being somehow consistent and homogenous gives the geographical location of the sampled sites. The
in terms of morphology of exoskeleton characters (Can- supralittoral zone of these beaches was sampled by
zoneri 1968; Aliquo ` and Soldati 2010). means of individual pitfall traps or by means of con-
Conversely, the P. bimaculata populations occurring stellations of pitfall traps, each of which consisted of
within the same geographical area demonstrate a high five plastic cups (diameter = 7.5 cm) buried with their
degree of polymorphism, with several populations already mouth flush with the surface of the sand and connected
being recognized as distinct taxa of intra-specific rank by means of thin wooden walkways. Such walkways

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