External, buccal and chondrocranial morphology, bone development and ecology of the tadpoles of Ramanella obscura, a narrow-mouthed frog species endemic to Sri Lanka is described. The tadpoles have a dorsoventrally flattend body, keratinous ridge on lower lip, a postnarial ridge that extends anteriorly between narial papillae and an expanded fenestrated sheet of cartilage associated with the larval otic process and processus lateralis posterior. But they do not possess a medial preglottal papilla in ventral buccal floor as in Microhyla. At Gosner stage 25, there is no bone development; but by stage 35, exoccipitals, parasphenoid, frontoparietals and prootics are developed. By stage 40, in addition to the bones at stage 35, nasals are formed. The tadpoles are tree-hole or small-ground-pool dwellers that feed on particulate matter and infusoria both in the substratum and the water column, for which they have morphological adaptations. No other anuran tadpoles were observed in syntopy with R. obscura tadpoles.
Key words: Chondrocranium; buccal morphology; tadpole ecology; endemic; Sri Lanka
CJSBS 2011; 40(2): 109-120