Ukuwela et al. (2015) found evidence for 34 divergences between lineages older than 0.5 Ma (candidate speciation events); 22 of these have > 0.7 posterior probabilities of occurring in Southeast Asia, 10 in Australasia, and 2 in the Indian Ocean. This implies most sea snake diversity in South East Asia originated from a period of rapid in situ evolution. While viviparous sea snakes originated in Australasia, Southeast Asia and its Indo-Australian Archipelago appears to be their primary centre of speciation. This is contrary to predictions of the overlap or accumulation models. Taxa are not more likely to disperse into, rather than out of, Southeast Asia and the Indo-Australian Archipelago.
The majority of sea snake diversiﬁcation, including the rapid core Hydrophis radiation, occurred during major climatic and geological events that drove vicariant population and species divergence in many of the region’s marine groups. Viviparous sea snakes might be particularly inﬂuenced by ‘soft’ biogeographical barriers (such as incomplete and thus permeable land bridges) because they give birth to live young and thus lack the dispersing planktonic larval stage that is expected to promote population connectivity in most other marine groups (many ﬁsh and invertebrates). Several sea snake species accordingly show strong intraspeciﬁc genetic structure corresponding to deep-water and historical land barriers. However, biogeographical patterns and the diversiﬁcation dynamics of the entire sea snake radiation have not previously been quantitatively investigated.
Ukuwela, Kanishka DB, Michael SY Lee, Arne R. Rasmussen, Anslem Silva, Bryan G. Fry, Parviz Ghezellou, Mohsen Rezaie‐Atagholipour, and Kate L. Sanders. 2015. Evaluating the drivers of Indo‐Pacific biodiversity: speciation and dispersal of sea snakes (Elapidae: Hydrophiinae). Journal of Biogeography (2015).