MORPHOLOGICAL VARIATION IN TADPOLES OF THE GEOCRINIA-LAEVIS COMPLEX -REGIONAL DIVERGENCE AND HYBRIDIZATION (AMPHIBIA, ANURA, MYOBATRACHINAE)

Morphological variation in tadpoles of Australian frogs of the Geocrin ia laevis complex was studied using specimens preserved at predetermin ed sizes, that had been reared under laboratory conditions from held-c ollected egg masses. Univariate and multivariate statistical analyses of 24 metric characters included comparisons of G. laevis with two dis junct population groups of G. victoriana, as well as descriptions of t he variation across a hybrid zone between the two species. Geocrinia v ictoriana differed from G. laevis by having shorter interpupillar dist ances, but longer tooth rows and more oral papillae. The two regional groups of G. victoriana were also distinct; larvae from south-western Victoria had the widest oral disks, whereas those from central Victori a showed the most narrowly positioned eyes. Most populations from the hybrid zone were more similar to G. laevis in tadpole morphology than in call parameters, adult morphology, or frequencies of allozyme marke rs. Morphological aberrations did not occur in increased frequencies i n larvae from the hybrid zone.