Wednesday, June 29, 2016

[Herpetology • 2016] Brachymeles dalawangdaliri • Additions to Philippine Slender Skinks of the Brachymeles bonitae Complex (Squamata: Scincidae) III: A New Species from Tablas Island

Tablas Slender Skink |  Brachymeles dalawangdaliri  
 Davis, Geheber, Watters, Penrod, Feller, Ashford, Kouri, Nguyen, Shauberger, Sheatsley, Winfrey, Wong, Sanguila, Brown & Siler, 2016.  


Studies of the diversity of Philippine amphibians and reptiles have resulted in the continued description of cryptic species. Species formerly thought to range across multiple recognized faunal regions are now considered to be assemblages of multiple unique species, each restricted to a single faunal region. This pattern continues to hold true when considering Philippine skinks of the genus Brachymeles. Recent studies have resulted in the description of numerous unique species with many exhibiting various degrees of digit loss or limb reduction, as well as suggesting that unique lineages are still present in the B. bonitae Complex. In this paper, we describe a new species of fossorial skink within this species complex from Tablas Island based on collections made nearly 50 years ago. Although no genetic data are available for the new species, examinations of morphological data (qualitative traits, meristic counts, and mensural measurements) support its distinction from all other members of the genus. Brachymeles dalawangdaliri sp. nov. is differentiated from other members of the genus based on a suite of unique phenotypic characteristics, including a small body size (SVL 66.0–80.9 mm), bidactyl fore-limbs, digitless, unidactyl, or bidactyl hind limbs, a high number of presacral vertebrae (49), the absence of auricular openings, and distinct dorsal head scale patterns. The description of the new species increases the diversity of endemic vertebrates recognized to occur in the Romblon Island Group in the central Philippines.

Keywords: Reptilia, biodiversity, endemism, faunal region, fossoriality, limb reduction, non-pentadactyl, pentadactyl, Romblon Island Group

Taxonomic account

Brachymeles dalawangdaliri sp. nov.

Brachymeles bonitae Duméril & Bibron 1839; Taylor 1917; Brown 1956:5; Brown & Rabor 1967:526; Brown & Alcala 1970; Brown & Alcala 1980:20; Davis et al. 2014; Geheber et al. 2016; Siler et al. 2016. 

Diagnosis. Following recent taxonomic revisions of Brachymeles (Siler et al. 2011; Davis et al. 2014) the new species is assigned to the B. bonitae Complex based on the following suite of morphological characters: (1) limbs present, (2) non-pentadactyl, (3) fore-limbs with 0–3 fingers. (4) hind limbs with 0–2 toes, (5) paravertebral scale rows ≥ 91, (6) presacral vertebrae 47–53, (7) supraoculars four, (8) enlarged, differentiated nuchals present, (9) longitudinal rows of dark spots around the body absent, and (10) auricular opening absent.
Brachymeles dalawangdaliri sp. nov. can be distinguished from congeners by the following combination of characters: (1) body size small (SVL 66.0–80.9 mm), (2) fore-limbs bidactyl, (3) hind limbs digitless, unidactyl, or bidactyl, (4) limb length short, (5) supralabials six or seven, (6) infralabials six or seven, (7) supraciliaries five, (8) supraoculars four, (9) midbody scale rows 24 or 25, (10) axilla–groin scale rows 80–83, (11) paravertebral scale rows 97–101, (12) prefrontal contact absent, (13) frontoparietal contact present or absent, (14) enlarged chin shields in two pairs, (15) nuchals enlarged, (16) auricular opening absent, (17) presacral vertebrae 49, and (18) uniform body color (Tables 1, 2).

Etymology. The name of the new species presented in this paper is derived from the Tagalog (Filipino) terms ‘dalawa,’ meaning two, and ‘daliri,’ meaning finger, referencing one of the defining characteristics of the new species, the two digits on the fore-limbs. Suggested common name: Tablas Slender Skink.

Distribution. Brachymeles dalawangdaliri sp. nov. is known only from Tablas Island, Romblon Island Group, Philippines (Fig. 1).

 Drew R. Davis, Aaron D. Geheber, Jessa L. Watters, Michelle L. Penrod, Kathryn D. Feller, Alissa Ashford, Josh Kouri, Daniel Nguyen, Kathryn Shauberger, Kyra Sheatsley, Claire Winfrey, Rachel Wong, Marites B. Sanguila, Rafe M. Brown and Cameron D. Siler. 2016.
 Additions to Philippine Slender Skinks of the Brachymeles bonitae Complex (Reptilia: Squamata: Scincidae) III: A New Species from Tablas Island.
Zootaxa. 4132(1); 30-43.  DOI: 10.11646/zootaxa.4132.1.3