Multilocus phylogeny and Bayesian estimates of species boundaries reveal hidden evolutionary relationships and cryptic diversity in Southeast Asian monitor lizards

• Published in: Molecular ecology Vol. 22; no. 13; pp. 3495 - 3510
• Main Authors: Welton, L. J, Siler, C. D, Oaks, J. R, Diesmos, A. C, Brown, R. M
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Scientific Publications 01.07.2013; Blackwell Publishing Ltd; Blackwell
• Subjects: Amphibia. Reptilia; Animal populations; Animals; Asia, Southeastern; Bayes Theorem; Bayesian analysis; Biodiversity; Biogeography; Biological and medical sciences; Biological evolution; Boundaries; conservation genetics; Conservation of Natural Resources; data collection; DNA, Mitochondrial - genetics; Evolution, Molecular; Evolutionary biology; Fundamental and applied biological sciences. Psychology; Genetic diversity; Genetic Loci; Genetic Speciation; Genetic Variation; Genetics of eukaryotes. Biological and molecular evolution; Haplotypes; India; Lacertilia; Lizards; Lizards - classification; Lizards - genetics; mitochondrial DNA; Molecular Sequence Data; nuclear DNA; Philippines; Phylogenetics; Phylogeny; Phylogeography; Population genetics, reproduction patterns; Population structure; Reptiles & amphibians; Sequence Alignment; Sequence Analysis, DNA; South East Asia; Southeast Asia; species delimitation; Species diversity; Varanus; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Water monitoring; South East Asia; India; Asia; South east Asia; Philippines; Asia, Southeastern; nuclear DNA; species delimitation; Taxonomy; Tropical zone; Philippines; Conservation; Diversity; Mitochondrial DNA; Phylogeny; Cryptic; Vertebrata; Southeast Asia; Sauria; Genetics; Reptilia; conservation genetics
• ISSN: 0962-1083; 1365-294X; 1365-294X
• DOI: 10.1111/mec.12324

Recent conceptual, technological and methodological advances in phylogenetics have enabled increasingly robust statistical species delimitation in studies of biodiversity. As the variety of evidence purporting species diversity has increased, so too have the kinds of tools and inferential power of methods for delimiting species. Here, we showcase an organismal system for a data‐rich, comparative molecular approach to evaluating strategies of species delimitation among monitor lizards of the genus Varanus. The water monitors (Varanus salvator Complex), a widespread group distributed throughout Southeast Asia and southern India, have been the subject of numerous taxonomic treatments, which have drawn recent attention due to the possibility of undocumented species diversity. To date, studies of this group have relied on purportedly diagnostic morphological characters, with no attention given to the genetic underpinnings of species diversity. Using a 5‐gene data set, we estimated phylogeny and used multilocus genetic networks, analysis of population structure and a Bayesian coalescent approach to infer species boundaries. Our results contradict previous systematic hypotheses, reveal surprising relationships between island and mainland lineages and uncover novel, cryptic evolutionary lineages (i.e. new putative species). Our study contributes to a growing body of literature suggesting that, used in concert with other sources of data (e.g. morphology, ecology, biogeography), multilocus genetic data can be highly informative to systematists and biodiversity specialists when attempting to estimate species diversity and identify conservation priorities. We recommend holding in abeyance taxonomic decisions until multiple, converging lines of evidence are available to best inform taxonomists, evolutionary biologists and conservationists.