Did biotic impoverishment facilitate phenomenal diversification in Sri Lanka?

摘要

Sri Lanka is currently experiencing a tremendous increase in novel descriptions of its endemic diversity. Recent phylogenetic analyses and taxonomic revisions from disparate groups are repeatedly reinforcing this independent nature of the island's diversity compared to Peninsular India. Given Sri Lanka's proximity to the mainland, such in situ speciation calls for an explanation. Here I propose a scenario, which builds upon the earlier observation that lineages on the Indian plate experienced significant turnover during its continental drift and subsequent climate change. I hypothesize that the degree of this past extinction was differential, with Sri Lanka experiencing a higher degree of impoverishment than Peninsular India. This difference created ecological opportunities and facilitated speciation in taxa that survived on the island or later reached the island. Testable predictions under this scenario of impoverishment are discussed and suitable groups for detailed studies in future are also highlighted.