Abstract
Andhra Pradesh, situated at the interface of the Eastern Ghats and the Deccan Plateau, harbours a poorly inventoried
amphibian fauna despite its high topographic and ecological heterogeneity. This study presents integrated morphological
and molecular characterization of 14 amphibian species sampled from six districts of Andhra Pradesh during the
monsoon seasons of 2018 and 2019. Morphometric measurements (18 variables per individual) and qualitative
characters (skin texture, toe-webbing, tympanum visibility, and colouration) were recorded for 284 individuals across
Anura (12 species) and Gymnophiona (2 species). Mitochondrial 16S rRNA gene sequences (550 bp) were generated for
84 individuals. Bayesian phylogenetic analysis resolved seven well-supported clades congruent with current family-level
taxonomy. Morphometric discriminant function analysis correctly assigned 91.4% of individuals to their species based on
eight morphometric ratios. Two populations of Nyctibatrachus cf. humayuni from the Nallamala Hills exhibited 16S
pairwise distances of 6.8-7.4% from reference sequences, suggesting the presence of at least one undescribed species.
Species distribution models fitted to climatic predictors identified 34.2% of suitable habitat as falling outside existing
protected area boundaries, highlighting substantial gaps in the current protected-area network for amphibian
conservation in Andhra Pradesh.