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MORPHOLOGICAL VARIATION IN INSULAR LACERTID LIZARDS 223
would indicate the occurrence of highly divergent
individuals in the population. As it is evident from fig. 8,
Podarcis raffonei is the most variable species. In
particular, the sample from Scoglio Faraglione (R3)
shows the highest variability and is morphologically
differentiated from the samples of Strombolicchio (R2)
and Vulcano (R4).
Fig. 5 Digitalized images of the cephalic scales of P. DISCUSSION
sicula, P. wagleriana, and P. raffonei. Parietal (white Landmark based morphometrics applied to the
square) and Sopraocular (white asterisks) scales were
found to be diagnostic for the three species. The skulls analysis of the cephalic scales of Podarcis raffonei, P.
are equal in size to allow comparison of shapes. sicula, and P. wagleriana was found to be a powerful
tool in the detection of the pattern of geographic
analysed samples show high morphometric variation (cf. variation and the phenetic relationships among and
fig. 8). In particular, the sample from Zingaro (Sicily, within species. The three species significantly differ
W1) shows a very reduced morphometric variability and from each other in both shape and size of the skull.
is morphologically differentiated from all other Podarcis sicula is characterized by narrow and long
populations. On the other hand, the sample from the rostral and nasal regions. On the contrary, in Podarcis
small island of Marettimo (W8) is characterized by a wagleriana the rostral and nasal regions are wider and
number of outliers and extremes of variation which shorter than in P. sicula. In Podarcis raffonei the shape
of the skull is intermediate between P. sicula and P.
wagleriana. The shape of the Parietal and Sopraocular
scales appears to be highly diagnostic and species-
specific, thus representing a useful tool for recognition
of the species (cf. fig. 5): they are much larger and wider
in Podarcis sicula than in P. wagleriana, while in P.
raffonei the shape of these scales is intermediate between
P. sicula and P. wagleriana.
Size is another important component of interspecific
variation. The three species are characterized by
different allometric static patterns, as revealed by the
relationship between size of the skull and body length.
Podarcis wagleriana is characterized both by a smaller
head and body length, while P. sicula has a larger head
and body length which is intermediate between P.
wagleriana and P. raffonei. Podarcis raffonei shows the
largest body length, but its head size is intermediate
between P. sicula and P. wagleriana.
According to the results of landmark based
morphometrics and biometric analysis, P. sicula and P.
wagleriana appear to be relatively differentiated from
each other, while P. raffonei seems to be phenetically
intermediate between P. sicula and P. wagleriana. It
must be noted that phenetic analyses are partially
congruent with allozyme and molecular investigations
(Capula, 1994a; Harris & Arnold, 1999, Vasconcelos et
al., 2006), which indicate that Podarcis sicula is
genetically differentiated from both P. wagleriana and P.
raffonei, and that Podarcis raffonei is genetically closely
related to P. wagleriana.
The analysis of the intraspecific variation in shape of
the cephalic scales indicates that P. sicula is the less
variable species. This pattern is evident both in the
