Molecular systematics, evolution, and ecology of Sri Lankan shrub-frogs (Rhacophorinae: Pseudophilautus).

摘要

Sri Lanka is home to a recently discovered, large endemic radiation of shrub frogs. I use a well-resolved molecular phylogeny (constructed using six nuclear and mitochondrial DNA fragments) of Sri Lankan shrub frogs to examine the evolutionary, systematic and biogeographic relationships of the group. My findings demonstrate that: (1) Sri Lanka is a global amphibian diversity hotspot; (2) Despite several ancient terrestrial connections between Sri Lanka and India, there has been little dispersal between the two landmasses, resulting in clade level endemicity in many faunal groups; (3) There are only two Rhacophorid genera in Sri Lanka (as opposed to the previously conceived four genera), one characterized by direct development ( Pseudophilautus) and the other by foam nesting (Polypedates ); (4) Pseudophilautus is highly speciose with nearly 100 species, of which about 85% are new to science (of which I describe eight as new species); (5) Many new species are montane forms that are threatened by impending climate change; (6) Sri Lankan and Indian Pseudophilautus are distinct from Southeast Asian Philautus , the genus in which they were previously placed; (7) A remarkable degree of extinctions of Pseudophilautus species (19 species, of which I describe two as new) has occurred; (8) Phylogenetic relationships among Rhacophorid genera indicate that direct-development has evolved twice within the family; (9) The Sri Lankan Pseudophilautus are characterized by two unique reproductive behaviors: nesting in excavations made in soil, and laying eggs on the underside of leaves; (10) Direct development in Pseudophilautus is similar to Eleutherodactylus in many ways, but also differs, suggesting that direct development can evolve in different ways; (11) The diversification of the major Rhacophorid lineages occurred after the late Cretaceous (KT) mass extinction (65 MYA); (12) The basal Rhacophorids are Southeast Asian in origin, and the extant Rhacophorid fauna of Sri Lanka and India seems to be later arrivals to the sub-continent; (13) The radiation of Pseudophilautus in Sri Lanka shows ecomorphological structure, with strong correlation between morphology, behavior and habitat use; (14) There are many instances of morphological and ecological convergence within the Sri Lankan radiation; (15) Species typically show a pattern of diversification across the three mountain massifs in Sri Lanka; (16) Pseudophilautus of Sri Lanka are highly threatened, and needs immediate conservation intervention to prevent further extinctions.