Slender Rainbow in the Leaves

Explanation: As long and as thin as my index finger is this Slender Rainbow Skink, momentarily caught between dashes for cover among the leaves on the ground.

My Australian mate, my U.S. biologist colleague, and I discovered this population in the open woodland along Manton Reservoir, near Palmerston, in the tropical "Top End" of Northern Territory, Australia. True to form was the habitat here, as individuals of this species are quite typically found among leaf litter near water bodies.

Slender rainbow skinks are found only in northern Australia. But they are common there, and thus their overall population status is rated as "Least Concern" on IUCN's Red List of Threatened Species, although it is unknown if there are any major threats impacting this species.

Even though this reptile is small, furtive, and inconspicuous, it comes from quite a family stock. It is one of an amazing array of 39 species of the genus Carlia, showing quite an "adaptive radiation" and speciation (divergence into many individual species from an original form), eventually inhabiting many niches and habitats of sclerophyll forest (that is, forest with plants evolved with thick, hard leaves so as to avoid moisture loss during the dry season).

Studies suggest Carlia rapidly diversified into 3 original clades and into all these 39 species during the early phase of its evolution, evolving far faster than its skink cousins residing in wet forests. Why this was the case is unclear ... an evolutionary mystery in search of a graduate student!

Unless you look very carefully at the array of lines, colors, and
shadows underfoot, you will miss this wonderful example
of adaptive radiation!

Information:
Dolman, G., and A.F. Hugall. 2008. Combined mitochondrial and nuclear data enhance resolution of a rapid radiation of Australian rainbow skinks (Scincidae: Carlia). Molecular Phylogenetics and Evolution 49(3):782-794.

EPOW - Ecology Picture of the Week