Inter‐island variation and taxonomy of Seychelles Trachylepis

Abstract

Skinks of the genus Trachylepis are geographically widespread and diverse. In the Seychelles islands two species are present, T. sechellensis and T. wrightii. All island populations of these two species were studied in 2000–2003 and the morphology of the populations compared to museum specimens. The two species are distinctive in morphology, although convergence occurs on some small islands occupied by large colonies of breeding sea birds. The taxon ’Mabuya wrightii ilotensis’ represents one example of this and was re‐identified as a form of T. sechellensis. The morphology of this population has changed over the last 67 years, probably as a result of the decline of the sea bird colony on the island. More extreme changes have occurred on other islands where the loss of sea bird colonies has been followed by the replacement of the sea bird specialist T. wrightii by the more generalist T. sechellensis. A reverse process of convergence towards the T. wrightii morphology was observed in recently established T. sechellensis populations on islands with large or increasing sea bird colonies. This highlights the adaptability of some island populations and the need to consider distinct islands as part of a metapopulation.