Spiny-tailed Monitor - Subspecies and Taxonomy

Subspecies and Taxonomy

The spiny-tailed monitor is part of an exclusively Australian radiation of small monitor lizards, the subgenus Odatria.

In the past, three subspecies of V. acanthurus were recognised: The continental subspecies V. a. acanthurus and V. a. brachyurus, and V. insulanicus, that only inhabits Groote Eylandt and the islands of the Wessel group. In 2006, the results of a study on the mtDNA of Australian monitors were published, according to which the two continental subspecies do not form natural (monophyletic), taxonomic entities. V. a. insulanicus was proven to be monophyletic, but it is more closely related to V. baritji than to other V. acanthurus. Therefore V. a. insulanicus might represent a distinct species. Wilson and Swan (2010) still accept V. a. insulanicus as a valid subspecies of V. acanthurus, which is easily distinguished from other spiny-tailed monitors by its dark colouration and more-banded pattern.