title: Uncoupling ecological innovation and speciation in sea snakes (Elapidae, Hydrophiinae, Hydrophiini).
abstract: The viviparous sea snakes (Hydrophiini) are by far the most successful living marine reptiles, with ∼ 60 species that comprise a prominent component of shallow-water marine ecosystems throughout the Indo-West Pacific. Phylogenetically nested within the ∼ 100 species of terrestrial Australo-Melanesian elapids (Hydrophiinae), molecular timescales suggest that the Hydrophiini are also very young, perhaps only ∼ 8-13 Myr old. Here, we use likelihood-based analyses of combined phylogenetic and taxonomic data for Hydrophiinae to show that the initial invasion of marine habitats was not accompanied by elevated diversification rates. Rather, a dramatic three to six-fold increase in diversification rates occurred at least 3-5 Myr after this transition, in a single nested clade: the Hydrophis group accounts for ∼ 80% of species richness in Hydrophiini and ∼ 35% of species richness in (terrestrial and marine) Hydrophiinae. Furthermore, other co-distributed lineages of viviparous sea snakes (and marine Laticauda, Acrochordus and homalopsid snakes) are not especially species rich. Invasion of the oceans has not (by itself) accelerated diversification in Hydrophiini; novelties characterizing the Hydrophis group alone must have contributed to its evolutionary and ecological success.
authors.affiliation: Darling Building, School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA, Australia. kate.sanders@adelaide.edu.au
authors.forename: K L
authors.initials: KL
authors.lastname: Sanders
authors.lastname: Mumpuni
authors.forename: M S Y
authors.initials: MS
authors.lastname: Lee
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D044822:Biodiversity; D017815:Elapidae / Q000235:genetics* / Q000502:physiology; D049810:Genetic Speciation; D016013:Likelihood Functions; D010802:Phylogeny