File Snake Phylogeny

Acrochordus javanicus. JCM

Filesnakes (Acrochordus) are unusual. They are completely aquatic, living in both fresh and salt water; they have baggy skin with rough scales containing sensory organs; and they the ability to stay underwater for long periods of time. Additionally, they have an Indo-Australian distribution. Three living species are recognized and a fourth species (A. dehmi) is known only from its fossilized vertebrae from Pakistan. One of these, the Elephant Trunk Snake (A. javanicus), is heavily hunted for its skin and meat.  Now, Sanders et al. have estimated divergence times for these snakes and looked at their phylogeny using morphology, fossils, and DNA. Their results show that A. javanicus (a South and Southeastern Asian endemic) is the sister to the Arafura Filesnake (A. arafurae) an Australasian endemic and the widespread, marine Little File Snake (A. granulatus). The divergence of the three extant species was dated at 20.3 MYA (million years ago) and A. granulatus diverged from A. arafurae 15.6 MYA. Their molecular data support the Acrochordids and Colubroidae as sister groups that separated about 62 MYA. Full citation: Sanders, K. L., Mumpuni, A. Hamidy, J. J. Head, and D. J. Gower. 2010. Phylogeny and divergence times of filesnakes (Acrochordus): inferences from morphology, fossils, and three molecular loci. Molecular Phylogenetics and Evolution 56:837-867.