Brachymeles Species Boundaries
There are only four groups of scincid lizards at the genus level which have species that are fully limbed as well as species without limbs. All species are known to burrow and live in dry, rotting material inside decaying logs or in loose soil and leaves. Many different populations within the genus Brachymeles look very similar, so identifying separate species within this genus is difficult.
In this paper, we provide an analysis and full description of the evolutionary history of species within Brachymeles, clear up uncertainties involved in distinguishing separate species, and illustrate many of these lizards for the first time.
We identify species as being distinct if they have sufficiently different appearances and genetics. Genetic analyses support the existence of nine unique species of Brachymeles. Body measurements agree on these nine species but also identified a 10th unique lineage from Jolo Island, previously thought to be part of B. talinis. No physical differences were observed between the sexes of any of these 10 species. Included in these 10 species are the four formerly recognized subspecies of B. boulengeri and two formerly recognized subspecies of B. schadenbergi which are now elevated to full species.
Siler, C.D. and R.M. Brown. 2010. Phylogeny-based species delimitation in Philippine slender Skinks (Reptilia: Squamata: Scincidae: Brachymeles): Taxonomic revision of pentadactyl species groups and description of three new species. Herpetological Monographs 24: 1–54. pdf