MORPHOLOGICAL TRAITS OF COMMON TOAD Bufo bufo ...

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Čađenović & Vukov: MORPHOLOGICAL TRAITS OF COMMON TOAD BUFO BUFO . . .
RESULTS AND DISCUSSION
Morphometric Characters
Former data on values of morphometric characters of the species Bufo bufo are
rather insufficient, or, some of them have been given only descriptively. That is why
we have presented here the average values for a large number of characters that
have not been previously analyzed and data about that do not exist in the literature.
Basic parameters of morphometric characters descriptive statistics have been
presented separately by sexes in the table 2. The smallest male of the sample of the
population from Biogradsko Lake is 64.28, and the largest one 82.54 mm. The
smallest female is 90.94 mm, and the largest 109.94 mm. Obtained values of body
size of common toad from Biogradsko Lake are within the limits of the so far recorded
values from other parts of areal of the species. (R a d o v a n o v i ć , 1951; A r n o l d and
B u r t o n , 1978; Đ urović et al, 1979 etc).
Sexual dimorphism has been analyzed in scope of population (localities) by
application of Tukey test for samples of unequal size (“Unequal N HSD Tukey” test).
This test has shown an expressed sexual dimorphism, where the females have higher
average values of analyzed traits (Table 2). On basis of calculated parameters of
descriptive statistics, separately by sexes and on basis of compared differences
between the sexes, it has been established that the females have statistically higher
values of all the characters, especially when the word is about L – body length, Lpa –
length of front extremity, Lc – head length, Ltc – head width, Lg – length of salivary
glands, weigth.
With the population of Biogradsko Lake a great number of traits that have been
demonstrating sexual dimorphism by the analysis of basic data where the size has
been included, indicate the absence of sexual dimorphism for the largest number of
characters when body size is excluded. The charactereistics which demonstrate the
presence of sexual dimorphism also after the eliminating body size are T- length of
tibiofibula and F – length of femur.
Females are bigger than males in a large number of amphibian species
(S h i n e , 1979; M i a u d et al., 1999; K h o n s u e et al.., 2001a, 2002b; M o n n e t and
C h e r r y , 2002). That has been especially expressed with tailless amphibians in
which females are bigger than males with 90% of species (S h i n e , 1979). This has
also been established in this paper for studied population from Biogradsko Lake, as
well as for the populations of the remaining part of the areal of distribution of this
species (G i t t i n s et al., 1980; H e m e l a a r , 1988). The most common explanation of
sexual dimorphism in body size is the advantge the females have in respect of eggs
production (H a l l i d a y and V e r r e l l , 1986; C v e t k o v i ć et al., 2003). Namely,
there is a positive correlation in many groups between body length and fecundity
(C u m m i n s , 1986; B e r v e n , 1988; S i n s c h , 1998; G i b b o n s and M c C a r t h y ,
1986). Assumption is that the selection, owing to a pointed correlation of body length