Convergent patterns suggest parallel processes of insular anuran diversification between oceanic archipelagos of the Southwest Pacific and the sky islands of the continental Western Ghats

Abstract

The unprecedented surge in frog species descriptions over the last two decades has been attributed to increasing access to remote regions, more advanced technology and techniques, and greater interest in these groups. The advent of genetic methods had been welcomed by practitioners as a boon in identifying species and their relationships. Suggestions were made that significant diversity was yet unrecognized and that the genetic tools would help uncover “cryptic” species that are not obvious. This notion, however, is contentious, and has been debated. As part of my dissertation thesis, I re-evaluate groups of frogs from two highly biodiverse tropical regions in the Western Ghats of India and the Philippines Archipelago of the Western Pacific. In my first chapter, I revisit a clade of Nyctibatrachus Nightfrogs in the Southern Western Ghats with an integrative approach utilizing morphologic, molecular, bioacoustic, developmental and life history data and reveal that species diversity may likely be inflated in that group (the Nyctibatrachus aliciae group). In my second chapter, I similarly reevaluate a clade of Philippine Limnonectes Fanged Frogs and find evidence to reconfigure species boundaries in the Limnonectes magnus clade. The third chapter addressed the same Limnonectes clade, but with genomic data using the newly developed FrogCap protocol, and finds geneflow between some groups identified in the previous chapter, but not so in other groups, reinforcing some species boundaries while questioning others. My fourth chapter evaluates a species complex of Philippine endemic Pulchrana Spotted Frogs in the eastern islands of the archipelago with genomic data. The results show that Pulchrana grandocula and P. similis cluster together as a group with the remaining Philippine species of Pulchrana forming another. I also find that two formerly recognized rare species represented by singleton specimens have highly admixed genotypes calling into question whether these are indeed unique taxa. My final chapter explores a higher level genomic dataset of frogs of the superfamily Ranoidea with the inclusion of the three paleoendemic Indian ranoid families of Nyctibatrachidae, Micrixalidae and Ranixalidae. My results show for the first time that these three families form a single clade representing an Indian subcontinent-wide ancient in-situ radiation. Additionally, preliminary biogeography results based on this dataset support of a “ferry India” model that suggests that several non-African crown groups of ranoids may have evolved on an insular India during its transit from Gondwana to become Eurasia.