Author

Utpal Smart

Graduation Semester and Year

2016

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Quantitative Biology

Department

Biology

First Advisor

Eric N Smith

Abstract

Much debated since the early 20th century, the evolutionary history and origin of the clinically important family Elapidae is of enormous interest. A persistent lack of higher-level phylogenetic resolution however, has impeded a clear understanding of the biogeography of this charismatic group of snakes. The traditional limiting factor in studies on higher-level elapid relationships has been the availability of samples from Old World coralsnakes (genera Sinomicrurus and Calliophis). Usually small, shy and fossorial, these animals are amongst the rarest Oriental snakes and their sampling in molecular studies has been sparse. Herein, primarily using molecular data, I work out the systematic relationships and biogeography of these two elusive genera of Asian coralsnakes. I leverage multilocus datasets, employing parametric phylogenetics and multispecies coalescent methods to provide a first insight into the systematic relationships and species boundaries of Calliophis species from South and Southeast Asia. I further use a phylogenetic framework to investigate biogeographic drivers of diversification in the Taiwan-Ryukyu Archipelago, using the genus Sinomicrurus. Finally, I estimate the most comprehensive phylogenetic relationships to-date among Old World coralsnakes and evaluate their position among the Elapidae. In doing so I make available one of the best resolved tree of higher-level elapid relationships to date. My phylogenetic analyses refute the monophyly of Old World coralsnakes and lead to a major revision of the known subfamilial relationships within Elapidae. Additionally, a fossil calibrated time-tree reveals that the genus Calliophis forms a distinct basal group in relation to all other elapids. My biogegoraphical analyses suggest that the Elapidae originated in Asia and the collision between the Indian and Laurasian plates may have acted as a driver of diversification in ancestral lineages. Overall, my dissertation work provides seminal information on the taxonomy, systematics and biogeography of one of the rarest and most enigmatic groups of venomous snakes in Asia. My research thus elucidates the role of major biogeographic breaks and also highlights novel patterns of evolutionary divergence across the Oriental biogeographic realm. This improved framework of phylogenetic relationships is expected to significantly benefit all future efforts of conservation and studies of toxin evolution in the Elapidae.

Keywords

Biogeography, Old World coralsnakes, Elapids, Molecular systematics

Disciplines

Biology | Life Sciences

Comments

Degree granted by The University of Texas at Arlington

Included in

Biology Commons

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