Parvoscincus duwendorum, Siler, Cameron D., Linkem, Charles W., Cobb, Kerry, Watters, Jessa L., Cummings, Sean T., Diesmos, Arvin C. & Brown, Rafe M., 2014

Siler, Cameron D., Linkem, Charles W., Cobb, Kerry, Watters, Jessa L., Cummings, Sean T., Diesmos, Arvin C. & Brown, Rafe M., 2014, Taxonomic revision of the semi-aquatic skink Parvoscincus leucospilos (Reptilia: Squamata: Scincidae), with description of three new species, Zootaxa 3847 (3), pp. 388-412 : 397-402

Parvoscincus duwendorum sp. nov.

( Figs. 3–5 )

Parvoscincus leucospilos Linkem, Diesmos, Brown, 2011 (part); Linkem & Brown, 2013 (part); Brown et al. 2012.

Holotype. PNM 9793 ( RMB Field No. 14261, formerly KU 329929), subadult, collected on 18 June 2011, on Mt. Pao, Barangay Adams, Municipality of Adams, Ilocos Norte Province, Luzon Island, Philippines (N: 18.438°, E: 120.878°; WGS-84; 750 m in elevation), by RMB.

Diagnosis. Parvoscincus duwendorum can be distinguished from congeners by the following combination of characters: (1) adult body size presumed medium (subadult SVL 33.5 mm); (2) Toe-IV lamellae 12; (3) supralabials seven; (4) infralabials eight; (5) midbody scale rows 26; (6) paravertebral scale rows 60; (7) prefrontals separated; (8) prefrontals contact first supraocular; (9) frontoparietals fused; (10) head pigmentation moderately mottled; (11) upper arm pigmentation present, patchy; (12) cloacal scale dark pigmentation absent; (13) subcaudal pigmentation absent; (14) dorsal white spots faint; (15) dorsal white bands 15; (16) tail dorsolaterally compressed; and (17) semi-aquatic (Tables 2, 3).

Comparisons. Characters distinguishing Parvoscincus duwendorum from all species of Parvoscincus are summarized in Tables 2 and 3. Parvoscincus duwendorum most closely resembles P. manananggalae , P. leucospilos , and P. tikbalangi . However, P. duwendorum differs from these three taxa by having Toe-IV lamellae 12 (vs. 17 [ P. manananggalae ], 15–17 [ P. leucospilos ], 14–16 [ P. tikbalangi ]), fewer midbody scale rows (26 vs. 32–33 [ P. manananggalae ], 30–34 [ P. leucospilos ], 28–32 [ P. tikbalangi ]), a greater number of dorsal white spot rows (15 vs. 9–13 [ P. leucospilos ], 9–12 [ P. manananggalae , P. tikbalangi ]), and the absence of precloacal scale dark pigmentation (vs. absence or presence [ P. leucospilos , P. tikbalangi ], presence [ P. manananggalae ]). Parvoscincus duwendorum further differs from P. leucospilos and P. manananggalae by having fewer paravertebral scale rows (60 vs. 61–67 [ P. leucospilos ], 61–69 [ P. manananggalae ]); from P. manananggalae and P. tikbalangi by having infralabials eight (vs. six or seven [ P. manananggalae ], seven [ P. tikbalangi ]); from P. leucospilos by having head pigmentation moderately mottled (vs. heavily mottled), and the presence of dark pigmentation on the upper arm surface (vs. absence); from P. manananggalae by having fewer longitudinal ventral scale rows (41 vs. 43–49), and the absence (vs. presence) of subcaudal dark pigmentation; from P. leucospilos and P. tikbalangi by having prefrontals separated (vs. in medial contact [ P. leucospilos ], separated or in medial contact [ P. tikbalangi ]); and from P. tikbalangi by having prefrontals and first supraoculars in contact (vs. separated).

TABLE 2. Distribution of diagnostic characters (+ present; 0 absent) among species in the genus Parvoscincus . Parvoscincus palawanensis does not have prefrontal scales. (A) Brown et al. 2010,

) Linkem and Brown, 2013, (C) Brown and Alcala 1980, (D) Ferner et al. 1997. Characters included for comparison are: snout–vent length (SVL), midbody scale-row count (MBSR), paravertebral scale-row count (PVSR), Toe-IV lamellae count (ToeIVlam), supralabial count (SL), infralabial count (IFL), number of anterior loreals, contact between profrontal scales, and microhabitat preference.

leucospilos duwendorum manananggalae tikbalangi

(6 m 1, 5 f) (1 juv.) (3 m, 2 f) (7 m, 1 f)

Paralectotype (CAS 64232) presumed male following visual inspection of external body; authors avoided creating incision on rare type specimen.

Description of holotype. Details of the head scalation are shown in Figure 4 . A subadult Parvoscincus , SVL 33.5 mm, with clawed, pentadactyl limbs. Head distinct from neck, characterized by enlarged jaw adductor musculature in temporal region. Snout sharply pointed in dorsal aspect, rounded in lateral aspect; rostral wide forming a nearly perpendicular margin with nasals and frontonasal; frontonasal equally wide as long, in contact with nasals, rostral, anterior loreal, and prefrontal scales; prefrontals broadly separated, in contact with anterior and posterior loreals, frontal, frontonasal, first supraciliary, and first supraocular; frontal greatly longer than wide, in contact with two supraoculars on right, two on left, rounded anteriorly, sharply rounded posteriorly; four enlarged supraoculars, first largest; single, large frontoparietals, in contact with supraoculars II–IV; interparietal arrowhead; parietals in moderate medial contact, in contact with fourth supraocular, postsupraocular, and secondary temporal; primary temporals two, ventral largest, overlapping dorsal; secondary temporals two, large, dorsal largest, ventral overlapping dorsal; tertiary temporals two, dorsal largest, ventral overlapping dorsal; auricular opening large.

Nasal pierced in center by large naris, surrounded anteriorly by rostral, dorsally by frontonasal, posteriorly by anterior loreal, and ventrally by first supralabial; anterior loreal one, posterior loreal equal in size; preoculars two; supralabials seven, fifth subocular; lower eyelid scaly and semi-transparent, nonscaled “window” absent; ear large, moderately sunk.

Infralabials eight, decreasing in size posteriorly in series; mental small, forming straight suture with single, large postmental and first infralabials; enlarged chin shields in three pairs; gular scales slightly smaller than ventrals.

Body elongate, cylindrical, slender, with 26 equal sized midbody scales, limbs overlapping when adpressed; paravertebral scales 60, imbricate, smooth, without striations, keels or pits. Tail elongate, dorsolaterally compressed, longer than body (TL [50.0] / SVL [33.5] 1.49); subcaudal scales nondifferentiated for basal half of tail, enlarged for distal half of original tail. Precloacal region with series of enlarged scales between pelvic region and cloaca, more elongate than ventral scales; medial precloacal scales larger.

FIGURE 6. Illustration of head of the examined Parvoscincus leucospilos paralectotype (CAS 64232) in dorsal and lateral 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; P, parietal; PF, prefrontal; PM, postmental; PO, preocular; PSO, presubocular; PoSO, postsupraoculars; R, rostral; SC, supraciliary; SL, supralabial; SO, supraocular; T1, primary temporal; T2, secondary temporal; and T3, tertiary temporal. Roman numerals indicate scales in the supraocular series. Illustrations by STC and CDS.

Forelimbs smaller than hind limbs, pentadactyl; forelimb scales slightly smaller in size than body scales, imbricate and smooth, reducing slightly in size closer to manus; lamellae becoming slightly keeled distally on each digit; relative digit length with lamellae V <I <II <III = IV; palmar scales irregular, raised, formal ventral protrusions from palmar surface. Hind limbs small, pentadactyl; hind limb scales equal in size and shape to body scales; dorsal scales on digits multiple. Lamellae keeled proximally and distally, flat for a few scales in between on Toe-IV; Toe-IV lamellae 12; relative digit length with lamellae I <II <III <V <IV; plantar scales irregular, slightly raised.

Coloration of holotype in preservative. The dorsal background color is medium brown, with tan mottling throughout. Two parallel light brown stripes run longitudinally down the body, starting at the base of the head and merging to one just past the start of the tail. Between these two stripes is a paravertebral row of darker brown spots. The venter color is a solid cream, without mottling. Along the lateral surface of the body, the dorsal and ventral color patterns merges in a scalloped pattern. There is a distinct cream spot on the forelimbs, just proximate to the body. The dorsal fore- and hind limbs possess the same mottling pattern present on the dorsal surface of the body. The ventral surfaces of the limbs are a solid cream color. The dorsal surface of the hands and feet are a mottled medium brown, with the exception of the cream-colored Finger I and Finger II on the forelimbs and Toe V on the hind limbs. The dorsal and dorsolateral surfaces of the head have a light and medium brown mottled pattern. This coloration transitions sharply into a cream and light brown mottled pattern ventrally. The labial scales are mottled light brown and cream. The ventral surface of the head is solid cream in color.

Color in life —Coloration in life did not differ substantially from the preserved holotype (RMB, personal observations).

Measurements and scale counts of holotype in mm. SVL 33.5; AGD 17.5; TotL 83.5; TL 50.0; HL 4.0; HW 7.7; SnFa 12.4; ED 1.5; SNL 2.7; IND 1.3; FLL 3.3; HLL 4.0; MBSR 26; PVSR 60; ToeIVlam 12; SL 7; IFL 8; SO 4.

Distribution, ecology and natural history. Parvoscincus duwendorum is known from a single specimen found at 750 elevation on Mt. Pao in the Ilocos Norte Province of northwestern Luzon Island ( Fig. 1 ). Although the species is recognized currently to occur in secondary-growth forest habitats, it is presumed the species also inhabits suitable primary forest. This species is semi-aquatic and can be found near riparian habitat. Parvoscincus duwendorum can be found in sympatry with Parvoscincus igorotorum , P. jimmymcguirei , and P. steerei . The new species was also observed on Mt. Cagua at 300–500 m ( Brown et al 2013b) but specimens eluded biologists by jumping in rapidly running montane streams.

At this time we are unable to appropriately evaluate this species against the IUCN criteria for classification due to the lack of available information about its distribution and natural history. We therefore classify this species Data Deficient DD (IUCN, 2010) pending future studies on this unique semi-aquatic forest skink.

Etymology. The specific epithet is a plaural derivation of the Filipino folklore term “Duwende,” which is chosen here to celebrate the country’s rich tradition of mythological forest animals and spirits. Duwendes are believed to be little fairy-like forest creatures, such as goblins, pixies, and elves, and believed to live in trees, termite mounds, and burrows in hillsides. The may bring bad or good fortune to humans and are often considered to be mischievous in nature. Suggested common name: Cordillera Aquatic Skink.

Figures

FIGURE 1. Map of the Luzon Island, Philippines, showing the collection localities for the new species and P. leucospilos.

FIGURE 3. Dorsal views of representative specimen heads and flanks, exhibiting pigmentation pattern variation among species.

FIGURE 4. Photographs of heads from dorsal and lateral perspectives to show pigmentation and scale pattern variation among species. With the exception of P. leucospilos (KU 313870), all photographs are of the holotypes of the new species.

FIGURE 5. Photographs in life of (A) P. leucospilos (Mt. Banahao; TNHC 62683); (B) P. leucospilos (Angat Watershed; KU 329388); (C) P. manananggalae sp. nov. (PNM 9794); and (D) P. tikbalangi sp. nov. (Holotype; PNM 9795).