Brachymeles ilocandia, Siler, Cameron D., Davis, Drew R., Freitas, Elyse S., Huron, Nicholas A., Geheber, Aaron D., Watters, Jessa L., Penrod, Michelle L., Papeș, Monica, Amrein, Andrew, Anwar, Alyssa, Cooper, Dontae, Hein, Tucker, Manning, Annalisa, Patel, Neeral, Pinaroc, Lauren, Diesmos, Arvin C., Diesmos, Mae L., Oliveros, Carl H. & Brown, Rafe M., 2016

Siler, Cameron D., Davis, Drew R., Freitas, Elyse S., Huron, Nicholas A., Geheber, Aaron D., Watters, Jessa L., Penrod, Michelle L., Papeș, Monica, Amrein, Andrew, Anwar, Alyssa, Cooper, Dontae, Hein, Tucker, Manning, Annalisa, Patel, Neeral, Pinaroc, Lauren, Diesmos, Arvin C., Diesmos, Mae L., Oliveros, Carl H. & Brown, Rafe M., 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), pp. 15-29 : 19-24

Brachymeles ilocandia sp. nov.

( Figs. 2 , 3 )

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.

Holotype. PNM 9819 ( RMB Field No. 7324, formerly KU 308004), adult female, collected under a decaying log in secondary-growth forest on 10 February 2007, Sitio Kauringan, Barangay Balatubat, Municipality of Calayan, Cagayan Province, Camiguin Norte Island, Philippines (18.902° N, 121.908° E; WGS 84; 303 m elev.), by J. Fernandez.

Paratypes (Paratopotypes). One adult female (KU 307967), collected on 8 February 2006 in Sitio Kauringan, Barangay Balatubat, Municipality of Calayan, Cagayan Province, Camiguin Norte Island, Philippines, by J. Fernandez and RMB. Four adult females, collected under a decaying log in secondary-growth forest on 11 February 2007 (KU 308019, 308020), 12 February 2007 (KU 308027), and 14 February 2007 (KU 308030) in Sitio Kauringan, Barangay Balatubat, Municipality of Calayan, Cagayan Province, Camiguin Norte Island, Philippines, by J. Fernandez and C. Oliveros.

Paratypes. One adult female (CAS 61377), collected in 1920 in Nayon, Ifugao Subprovince, Mountain Province, Luzon Island, Philippines. One adult female (FMNH 259449), collected on 10 March 2001 in Kalinga Province, Luzon Island, Philippines, by RMB and ACD. One adult female (KU 304567), collected on 5 March 2006 in “Limandok,” Barangay Balatabat, Municipality of Calayan, Cagayan Province, Camiguin Norte Island, Philippines (18.92927° N, 121.89881° E; WGS 84; 403 m elev.), by J. Fernandez and RMB.

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).

Comparisons. Brachymeles ilocandia sp. nov. can be distinguished from B. bonitae by having fewer axilla– groin scale rows (80–82 versus 83–90) and fewer paravertebral scale rows (97–100 versus 103–110); from B. ligtas by having a greater number axilla–groin scale rows (80–82 versus 74–76), paravertebral scale rows (97–100 versus 91–93), and fewer presacral vertebrae (47 versus 50); from B. isangdaliri by having fewer supraciliaries (5 versus 6), the presence (versus absence) of a third chin shield pair, and a longer snout–vent length (65.7–77.6 mm versus 59.5); from B. mapalanggaon by having a longer fore-limb length (1.1–1.4 mm versus 0.8–1.0); from B. tridactylus by having a shorter fore-limb length (1.1–1.4 mm versus 1.5–2.5); from B. isangdaliri and B. mapalanggaon by having a longer total length (122.3–146.0 mm versus 106.1 [ B. isangdaliri ] or 120.2 [ B. mapalanggaon ]); from B. isangdaliri and B. tridactylus by having digitless limbs (versus unidactyl [ B. isangdaliri ] or tridactyl [ B. tridactylus ]), a greater number of presacral vertebrae (50–53 versus 47 [ B. isangdaliri , B. tridactylus ]), greater number of axilla–groin scale rows (80–82 versus 73 [ B. isangdaliri ] or 72–79 [ B. tridactylus ]), and a shorter hindlimb length (1.6–1.9 mm versus 2.2 [ B. isangdaliri ] or 2.6–3.6 [ B. tridactylus ]).

Brachymeles ilocandia sp. nov. can be distinguished from all limbless species of Brachymeles by having limbs, and from all pentadactyl species of Brachymeles by having digitless limbs.

Description of holotype. Details of the head scalation are shown in Figures 2 and 3 . Adult, female, body small, slender, SVL 74.2 mm; head weakly differentiated from neck, nearly as wide as body, HW 5.9% SVL, 86.4% HL; HL 38.4% SnFa; SnFa 17.8% SVL; snout broadly rounded in dorsal and lateral profile, SNL 60.0% HL; ear completely hidden by scales; eyes small, ED 15.9% HL, 42.0% END, pupil subcircular; body slightly depressed, nearly uniform in thickness, MBW 129.1% MBH; scales smooth, glossy, imbricate; longitudinal scale rows at midbody 23; paravertebral scale rows 97; axilla–groin scale rows 80; limbs short, diminutive, bluntly rounded; digits absent; finger and toe lamellae absent; FLL 2.0% AGD, 1.5% SVL; HLL 3.0% AGD, 2.3% SVL; tail not as wide as body, gradually tapered towards end, TW 87.2% MBW, TL 83.3% SVL.

Rostral projecting onto dorsal snout to level in line with midline nasal, roughly equal in width and height, in contact with frontonasal; frontonasal wider than long; nostril ovoid, in posterodorsal corner of single trapezoidal nasal, longer axis directed posterodorsally and anteroventrally; supranasals present; postnasals absent; prefrontals narrowly separated; frontal roughly diamond-shaped, its anterior margin in moderate contact with frontonasal, in contact with first two anterior supraoculars, 4× wider than anterior supraocular; supraoculars four; frontoparietals moderate, moderately separated, each frontoparietal in contact with supraoculars two and three; interparietal large, its length roughly equal to 2× midline length of frontoparietal, longer than wide, diamond-shaped, wider anteriorly, pineal eyespot visible in center; parietals broader than frontoparietals, in broad contact behind interparietal; enlarged nuchals present; loreals two, anterior loreal slightly longer and higher than posterior loreal; preocular one; presubocular one; supraciliaries five, the anteriormost contacting prefrontal and separating posterior loreal from first supraocular, posteriormost extending to midline of fourth supraocular; subocular scale row single, incomplete, in contact with supralabials; lower eyelid with one row of scales; supralabials six, first nearly twice the width of others, third, fourth and fifth subocular; infralabials five ( Fig. 2 ).

Mental wider than long, fused with first infralabials; postmental single, enlarged, its width narrower than width of mental; followed by three pairs of enlarged chin shields, first pair narrowly separated, second pair largest, narrowly separated, third pair smallest, broadly separated by three medial scales ( Fig. 2 ). Scales on limbs smaller than body scales.

Variation. Differences in scalation patterns were observed among the type series. Observed scale row counts variation included: midbody scale rows of 22 (FMNH 259449, KU 308030), 23 (CAS 61377, KU 307967, 308004, 308019, 308027), and 24 (KU 304567, 308020); axilla–groin scale rows of 80 (CAS 61377, FMNH 259449, KU 308004, 308030), 81 (KU 307967, 308019, 308020), and 82 (KU 304567, 308027); paravertebral scale rows of 97 (KU 308004), 98 (FMNH 259449, KU 307967, 308019, 308020, 308030), 99 (CAS 61377), and 100 (KU 304567, 308027); and five (KU 308004, 308027, 308030) or six (CAS 61377, FMNH 259449, KU 304567, 307967, 308019, 308020) infralabials. Additionally, a low level of variation was observed in the presence of a fused mental and first infralabial scale (both sides of head in KU 308004 and 308030, right side of head only in KU 308027). This character was absent in all other specimens examined.

Coloration of holotype in life. Coloration in life is unrecorded; however, because Brachymeles specimens do not change significantly during preservation (CDS, RMB personal observations), we suspect that the preserved coloration and patterns are much like those in life.

Coloration of holotype in preservative. The dorsal, lateral and ventral regions of the trunk and tail are a solid Prout’s Brown (Color 47; Köhler 2012). The head has the same background color, with dense speckling on the dorsal and lateral surfaces, causing the head to appear more Hair Brown (Color 277; Köhler 2012) in color. In the vicinity of each orbit there is a Fuscous (Color 283; Köhler 2012) splotch. The ventral region of the head is the same solid Prout’s Brown (Color 47; Köhler 2012) as the trunk.

Diagnostic character bonitae ilocandia sp. nov. isangdaliri ligtas mapalanggaon tridactylus (3 m, 1 f) (9 f) (1 f) (3 m, 2 f) (3 m, 6 f) (12 m, 9 f)

Number of digits (fingers/toes) 0/0 1 0/0 1/1 2/0 0/0 3/3 2/1 1

PSV 53 50 – 53 47 50 51 47

MBSR 21 – 24 22 – 24 22 22 22, 23 22 – 24

AGSR 83 – 90 80 – 82 73 74 – 76 80 – 84 72 – 79

PVSR 103 – 110 97 – 100 97 91 – 93 99 – 102 90 – 98 6 6 6 6 6 6 (13) 7 (8) 5 5 (3) 6 6 5 (8) 6 (13) 6 (6) 6 (1) 7 (8) 5 5 6 5 5 5 4 4 4 4 4 4

Prefrontal contact Absent Absent or Point Absent Absent Absent Absent contact

Frontoparietal contact Absent Absent Absent Present Point contact or Absent Absent

chin shield pair contact Absent Absent Absent Present or Absent Absent Present or Absent

chin shield pair Present Present Absent Present Present or Absent Present

Mental/1st IFL fusion Present Present or Absent Absent Absent Present or Absent Absent

Enlarged nuchals Present Present Present Present Present Present

Longitudinal rows of dark spots Absent Absent Absent Absent Absent Absent

Observed for two individuals.

Distribution, ecology and natural history. Brachymeles ilocandia sp. nov. is known only from northern Luzon and Camiguin Norte islands ( Fig. 1 A). 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 B. bonitae 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. bicolor , B. 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.

Figures

FIGURE 1. (A) Map of the Philippines islands, with labels for islands discussed in the study, the five recognized major PAICs, major island groups, and additional deep-water islands provided for reference. Current islands in the Philippines are shown in medium grey to black; light gray areas enclosed in black 120 m bathymetric contours indicate the hypothesized maximum extent of land during the mid- to late Pleistocene. Vouchered localities for Brachymeles ilocandia sp. nov. marked by red circles. (B) Mapped output of Maxent results as the mean ecological niche model of suitable climatic conditions for Brachymeles ilocandia sp. nov. projected across the known distribution of the genus throughout the Philippines. Values corresponding to the likelihood of climatic suitability are included for scale and interpretation of heat map color-coding. Values are logistic-transformed for ease of interpretation on a scale of 0 – 1, according to the default Maxent output settings (ENM analysis and projection performed by NAH and MP).

FIGURE 2. Illustration of head of Brachymeles ilocandia sp. nov. (PNM 9819, holotype) in dorsal, lateral, and ventral views. Taxonomically diagnostic head scales are labeled as follows: C, chin shield; F, frontal; FN, frontonasal; FP, frontoparietal; IL, infralabial; IP, interparietal; L, loreal; M, mental; N, nasal; Nu, nuchal; P, parietal; PF, prefrontal; PM, postmental; PO, preocular; PSO, presubocular; R, rostral; SC, supraciliary; SL, supralabial; SN, supranasal; and SO, supraocular. Roman numerals indicate scales in the supraocular series, with Arabic numbers indicating scales in the supraciliary series. Illustrations by MLP and CDS.

FIGURE 3. Photograph of dorsal, lateral, and ventral views of head of the preserved holotype of Brachymeles ilocandia sp. nov. (PNM 9819). Photographs taken by JLW and MLP.

Tables

TABLE 1. Summary of mensural characters among species of the Brachymeles bonitae Complex. Sample size, body length and total length among males and females, and general geographical distribution (PAIC = Pleistocene Aggregate Island Complexes, sensu Brown & Diesmos [2002]) are included for reference (SVL, TotL, FLL, and HLL given as range over mean ± standard deviation; all body proportions given as percentage over mean ± standard deviation).

	bonitae ilocandia sp. nov. isangdaliri (3 m, 1 f) (9 f) (1 f)	ligtas (3 m, 2 f)	mapalanggaon (3 m, 6 f)	tridactylus (12 m, 9 f)
Range	Luzon & Polillo Luzon & Camiguin Luzon Island islands Norte islands	Lubang Island	Masbate Island	West Visayan PAIC
SVL (f) SVL (m)	69.4 65.7–77.6 59.5 (73.7 ± 3.7) 69.7–78.4 N/A N/A (72.8 ± 4.8)	60.7–69.2 (65.0 ± 6.0) 69.4–79.6 (74.5 ± 5.1)	61.7–75.8 (67.2 ± 5.4) 65.1–72.7 (68.4 ± 3.9)	59.9–82.3 (71.4 ± 6.9) 60.7–77.6 (69.0 ± 6.0)
TotL (f) TotL (m)	N/A 122.3–146.0 106.1 (134.1 ± 8.0) 122.0 N/A N/A	119.4 160.6	120.2 112.6–118.6 (115.6 ± 4.3)	133.6 120.9–154.1 (136.0 ± 9.8)
TL/SVL	73 81–90 78 (85 ± 3)	97–102 (99 ± 4)	67–84 (78 ± 9)	85–112 (95 ± 10)
FLL	1.0–1.7 1.1–1.4 1.3 (1.3 ± 0.3) (1.3 ± 0.1)	1.2–1.4 (1.3 ± 0.1)	0.8–1.0 (0.9 ± 0.1)	1.5–2.5 (2.0 ± 0.3)
FLL/SVL	1–2 1–2 2 (2 ± 0) (2 ± 0)	2–2 (2 ± 0)	1–2 (1 ± 0)	2–4 (3 ± 0)
HLL	1.5–2.3 1.6–1.9 2.2 (1.9 ± 0.3) (1.8 ± 0.1)	1.6–2.0 (1.8 ± 0.1)	1.2–1.6 (1.4 ± 0.1)	2.6–3.6 (3.1 ± 0.3)
HLL/SVL	2–3 2–3 4 (3 ± 0) (2 ± 0)	2–3 (3 ± 0)	2–2 (2 ± 0)	3–6 (5 ± 1)