Or a post previously titled, “Revision of the genus Sphenomorphus.”

My last post for Earth week 2012 is about the review of the species-rich genus Sphenomorphus.  “Sphenomorphus currently serves as a “wastebin taxon”  for a large number of skinks”, according to wikipedia.

The authors note that “(1) previously recognized species group relationships were misled by phenotypic convergence; (2) Sphenomorphus is widely paraphyletic; and (3) multiple lineages have independently invaded the Philippines.”

In other words, (1) the delineation of the group was obscured by the seemingly similar external features; (2) species in the genus Sphenomorphus did not belong to the same evolutionary family;  and (3) the Philippines was invaded by different groups independently. They arrived at these conclusions by studying the molecular evolutionary relationships of the species.

The authors proposed a revision in the generic level based on their study. They expanded/ resurrected 4 previously recognized genera and suggested 2 new genera to accommodate the diverse species in the Philippines.

The first genus that the authors suggested was Tytthoscincus or the diminutive Asian skink.  The genus name is from the Greek tytthos which means small and the Latin scincus for lizard. The type species is Tytthoscincus hallieri.

The second genus that they proposed was Pinoyscincus or the Filipino skinks. The genus name is from Pinoy, the Tagalog endearment term for Filipinos.  “The  species in this genus share a unique morphology of the hemipenis. The main shaft of the hemipenis, before the bifurcation (bifurcation = split), is wide with a large bulbous lobe on each lateral side of the shaft.” See figure above.

The type species is Pinoyscincus jagori.

They resurrected the following  genera:

1) Insulasaurus

The authors suggested that this clade is worthy of designation as a genus because the species share unique characteristics, and are biogeographically limited to some islands. Most of the species in this genus are from Palawan and Panay Island. The type species is Insulasaurus wrighti.

2) Otosaurus

The type species is Otosaurus cumingi which has always been  different morphologically to other Philippine skinks. The authors said that their “genetic and morphological results confirm its uniqueness amongst other lineages.”

They expanded the following:

1) Parvoscincus

The expanded genus  include “other small-bodied species in this Philippine clade (Parvoscincus leucospilos, Parvoscincus tagapayao, Parvoscincus luzonensis, Parvoscincus lawtoni, Parvoscincus kitangladensis, Parvoscincus laterimaculatus, Parvoscincus steerei, Parvoscincus decipiens) in addition to the secondarily enlarged, montane forest species (Parvoscincus beyeri, Parvoscincus boyingi, Parvoscincus igorotorum, and Parvoscincus hadros)

2) Scincella

Scincella cherriei and Scincella assata were added to this American genus.  They used to be in the genus Sphenomorphus.

Lesson for this post:  Too much information!

GALLERY (Click an image below to go to Gallery view.)

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Journal reference:
[1] LINKEM, C., DIESMOS, A., & BROWN, R. (2011). Molecular systematics of the Philippine forest skinks (Squamata: Scincidae: Sphenomorphus): testing morphological hypotheses of interspecific relationships Zoological Journal of the Linnean Society, 163 (4), 1217-1243 DOI: 10.1111/j.1096-3642.2011.00747.x