Skeletal ontogeny of frog lineages in Sri Lanka and India My undergraduate project was to re-affirm the phylogenetic relationships between five species representing three disparate lineages of Old World tree frogs by analyzing their ontogeny. I analyzed a series of tadpoles of different evolutionary lineages (differentially stained for bone and cartilage) across developmental stages to observe the skeletal ontogeny and ossification patterns correlated with their habitat changes (Senevirathne et al., 2018). Subsequent work included studying of the ontogeny of the Indian purple frog, Nasikabatrachus sahyadrensis, a recently-discovered monotypic frog family, an ancient Jurassic lineage often referred as the "coelacanth frog," completely fossorial and emerging only to breed during the monsoon. Its suctorial larva clinging to substrates in rapid mountain torrents, metamorphosing rapidly to a digging froglet, showing rapid cranial modifications associated with clinging to digging. I analyzed a series of tadpoles (differentially-stained for bone and cartilage). starting from stage 25-46, to observe the skeletal ontogeny correlated with their habitat changes (Senevirathne et al., 2016a). We analyzed taxonomically well-known ancient family, Micrixalidae or “Dancing Frogs,” endemic to the western mountains of India, surprisingly, the only lineage for which a tadpole was not known. We explored forests of Kerala, living with a family of forest people (Kani tribe), night trekking amidst elephants and gaur, and scrutinizing forest-covered mountain-streams for tadpoles (Senevirathne et al., 2016b).

Phenotypic and Genetics changes behind an evolutionary novelty: the urostyle Phenotypic and genotypic changes from an existing ancestral condition highlights the evolution of “key innovations”. These evolutionary novelties could be either structural (new body plans or structures) or functional. Functional novelties focus on novel functions whereas the structural ones are considered to have no homologous structures in ancestral lineages (e.g., in the fossil record). Phenotypic changes of a structural novelty would reflect changes in the corresponding genotypic/gene regulatory networks. As an undergraduate in Professor Meegaskumbura’s lab, I studied and compared the patterns of skeletal ontogeny in frog lineages across an island (Sri Lanka) and mainland (India) habitats.