Wednesday, June 29, 2016

[Herpetology • 2016] Brachymeles ilocandia • Additions to Philippine Slender Skinks of the Brachymeles bonitae Complex (Squamata: Scincidae) II: A New Species from the northern Philippines

Ilokano Slender Skink |  Brachymeles ilocandia 
Siler, Davis, Freitas, Huron, Geheber, Watters, Penrod, Papeș, Amrein, Anwar, Cooper, Hein, Manning, Patel, Pinaroc, Diesmos, Diesmos, Oliveros & Brown. 2016.    DOI: 10.11646/zootaxa.4132.1.2 


We describe a new digitless scincid lizard of the genus Brachymeles from northern Luzon and Camiguin Norte islands in the Philippines. This species belongs to the Brachymeles bonitae Complex, and both molecular and morphological data confirm that this species is distinct from all other congeners. Formerly considered to be a single widespread species, this group of species has been the focus of recent systematic reviews. Here we describe a new species in the B. bonitae Complex, recognized currently to constitute five species. Brachymeles ilocandia sp. nov. is the second digitless and the seventeenth non-pentadactyl species in genus. The description of this species brings the total number of species in the genus to 40, and provides new insight into unique distribution patterns of species of the northern Philippines.

Keywords: Reptilia, Babuyan Island Group, biodiversity, ecological niche modeling, endemism, faunal region, fossorial, Luzon Island, non-pentadactyl, pentadactyl

Brachymeles ilocandia 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.

Diagnosis. Following recent taxonomic revisions of Brachymeles (Siler et al. 2011; Davis et al. 2014; Geheber et al. 2016) 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 ilocandia sp. nov. can be distinguished from congeners by the following combination of characters: (1) body size small (SVL 65.7–77.6 mm), (2) limbs digitless, (3) limb length short, (4) supralabials six, (5) infralabials five or six, (6) supraciliaries five, (7) supraoculars four, (8) midbody scale rows 22–24, (9) axilla–groin scale rows 80–82, (10) paravertebral scale rows 97–100, (11) mental/first infralabial fusion present or absent, (12) prefrontal contact absent or in point contact, (13) frontoparietal contact present, (14) enlarged chin shields in three pairs, (15) nuchals enlarged, (16) auricular opening absent, (17) presacral vertebrae 50–53, and (18) uniform body color (Tables 1, 2).

Distribution, ecology and natural history. Brachymeles ilocandia sp. nov. is known only from northern Luzon and Camiguin Norte islands (Fig. 1A). The new species likely once occurred in low- to mid-elevation primary forest habitats; however, all recent observations of this species have occurred in secondary growth forest habitats. In contrast to the other members of the Bbonitae Complex, this species appears to be quite common in secondary growth forest fragments throughout the northern Philippines.  Brachymeles ilocandia sp. nov. is found in parts of its distribution with B. bicolorB. kadwa, and B. boulengeri. Other species of Brachymeles known to occur in the Luzon PAIC include B. bicolandia, B. bonitae, B. brevidactylus, B. cobos, B. elerae, B. isangdaliri, B. kadwa, B. lukbani, B. makusog, B. minimus, B. muntingkamay, and B. wrighti (Davis et al. 2014). 

We have evaluated this species against the International Union for Conservation of Nature (IUCN) criteria for classification and find that it does not qualify for Critically Endangered, Endangered, Vulnerable, or Near Threatened status. Not only does B. ilocandia sp. nov. occur on more than one island, but also the species appears common in secondary growth and disturbed habitats throughout its recognized distribution. Therefore, we recommend that this species be classified as Least Concern, LC (IUCN 2015).

Etymology. The specific epithet is chosen in reference to the biogeographically and culturally distinct homeland, “Ilocandia”, of the Ilokano people of the northern Philippines, the third largest ethnolinguistic group in the country. Including the Babuyan Island Group north of Luzon Island, Ilocandia stretches from the western coast of northern Luzon, across the Cagayan Valley, to parts of central Luzon and the boundaries of Aurora Province in the east. The region is home to many endemic vertebrates, diverse geographic landscape, unique local cuisine, and rich cultural traditions. Suggested common name: Ilokano Slender Skink.

Cameron D. Siler, Drew R. Davis, Elyse S. Freitas, Nicholas A. Huron, Aaron D. Geheber, Jessa L. Watters, Michelle L. Penrod, Monica Papeș, Andrew Amrein, Alyssa Anwar, Dontae Cooper, Tucker Hein, Annalisa Manning, Neeral Patel, Lauren Pinaroc, Arvin C. Diesmos, Mae L. Diesmos, Carl H. Oliveros, and Rafe M. Brown. 2016.
Additions to Philippine Slender Skinks of the Brachymeles bonitae Complex (Reptilia: Squamata: Scincidae) II: A New Species from the northern Philippines.
Zootaxa. 4132(1); DOI: 10.11646/zootaxa.4132.1.2