Pseudogekko isapa, Siler, Cameron D., Davis, Drew R., Diesmos, Arvin C., Guinto, Faith, Whitsett, Collin & Brown, Rafe M., 2016

Siler, Cameron D., Davis, Drew R., Diesmos, Arvin C., Guinto, Faith, Whitsett, Collin & Brown, Rafe M., 2016, A new species of Pseudogekko (Squamata: Gekkonidae) from the Romblon Island Group, Central Philippines, Zootaxa 4139 (2), pp. 248-260 : 249-255

Pseudogekko isapa sp. nov.

( Fig. 2 )

Holotype. PNM 9816 ( ACD Field No. 8920), adult male, collected at 21:30 hrs in 2014, in Mt. Guiting-Guiting Natural Park, Municipality of Magdiwang, Barangay Talaba, Romblon Province, Sibuyan Island, Philippines (12.401873°N, 122.539747°E; WGS 84; 479 m elev.), by ACD and party.

Paratype. One adult female ( CAS 139713) collected on 22 May 1972, on a small vine in secondary forest, from Dubduban Barrio, Municipality of San Agustin, Romblon Province, Tablas Island, Philippines (12.58332°N, 122.1°E; WGS 84; ~ 17 m elev.), by L. C. Alcala and party.

Diagnosis. Pseudogekko isapa sp. nov. can be distinguished from congeners by the following combination of characters: (1) body elongate (SVL 62.1, 63.4 mm), (2) axilla–groin distance long (32.1, 33.0 mm), (3) relative head length long (19% SVL), (4) relative snout length long (62, 64% head length), (5) Finger-III scansors 13, (6) Toe-IV scansors 17, (7) paravertebrals 240, 246, (8) ventral scales 135, 141, (9) supralabials 20, 21, (10) infralabials 17, 19, (11) circumorbitals 50, 54, (12) precloacal pores 15 in males, none in females, (13) femoral pores absent, (14) conspicuous head spotting present, (15) conspicuous dorsolateral spotting absent, (16) body striping absent, and (17) interorbital banding present (Tables 1, 2; Fig. 2 ).

Comparisons. Characters distinguishing Pseudogekko isapa sp. nov. from all other species of the Pseudogekko compresicorpus Complex sensu Siler et al. (2014b) are summarized in Tables 1, 2. Pseudogekko isapa sp. nov. most closely resembles P. compresicorpus ; however, it differs from this species by having a longer snout–vent length (SVL 62.1–63.4 mm versus 54.9–59.7 mm), wider body width (midbody width 8.5–8.9 mm versus 5.4–6.7 mm), greater relative head length (head length 19% SVL versus 16–18%), fewer Finger-III (13 versus 15–17) and Toe-IV (17 versus 18 or 19) scansors, more (17–19 versus 13–16), more circumorbitals (50–54 versus 39–45), more paravertebrals (240–246 versus 226–234), more ventrals (135–141 versus 127–130), and more enlarged precloacal pore-bearing scales (15 versus 10–14; Fig. 2 ).

From the remaining members of the P. compresicorpus Complex, P. isapa sp. nov. can be distinguished from P. pungkaypinit by having a smaller body size (SVL 62.1–63.4 mm versus 66.6–76.8 mm), smaller axilla–groin distance (32.1–33.0 mm versus 37.2–41.2), longer relative snout length (62–64% head length versus 54–60%), fewer Finger-III scansors (13 versus 15–17), fewer paravertebrals (240–246 versus 265–280), fewer enlarged pore-bearing precloacals (15 versus 17–20), and the absence (versus presence) of body striping; and from P. chavacano and P. ditoy by having a larger body size (SVL 62.1–63.4 mm versus 54.7–55.9 [ P. chavacano ] or 49.4– 52.6 [P. d i t o y]), larger axilla–groin distance (32.1–33.0 mm versus 26.7–30.0 [ P. chavacano ] or 25.1–29.7 [ P. ditoy ]), longer relative snout length (62–64% head length versus 55–58% [ P. chavacano ] or 57–59% [ P. ditoy ]), fewer Finger-III scansors (13 versus 15 or 16 [ P. chavacano ] or 14 or 15 [P. d i t oy]) and enlarged pore-bearing precloacals (15 versus 16 [ P. chavacano ] or 18 [ P. ditoy ]), and more circumorbitals (50–54 versus 46 [ P. chavacano ] or 40–43 [P. d i t oy]), paravertebrals (240–246 versus 195–197 [ P. chavacano ] or 180–185 [ P. ditoy ]), and ventrals (135–141 versus 122 or 123 [ P. chavacano ] or 111–118 [ P. ditoy ]; Tables 1, 2).

Pseudogekko isapa sp. nov. can be distinguished from members of the P. brevipes Complex ( P. brevipes , P. atiorum ), by having a larger body size (SVL 62.1–63.4 mm versus 41.1–52.5 [P. a t i o r u m] or 34.5–42.4 [ P. brevipes ]), more supralabials (20 or 21 versus 15–17 [P. a ti o ru m] or 13 or 14 [ P. brevipes ]), infralabials (17–19 versus 12–15 [P. a t io ru m] or 14 or 15 [ P. brevipes ]), circumorbitals (50–54 versus 35–38 [ P. atiorum ] or 33–35 [ P. brevipes ]), and ventrals (135–141 versus 119–129 [ P. atiorum ] or 96–117 [ P. brevipes ]).

From P. smaragdinus , P. isapa sp. nov. can be distinguished by having fewer Finger-III scansors (13 versus 15– 18) and lacking pore-bearing femorals (15 versus 32–41), more supralabials (20 or 21 versus 16–19), circumorbitals (50–54 versus 33–35), and ventrals scales (135–141 versus 124–130), a tendency towards having fewer Toe-IV scansors (17 versus 16–22), a tendancy towards having more infralabials (17 or 19 versus 14–17), and by the presence of brownish tan (versus yellow to orange [undisturbed] or neon green [disturbed]) body coloration, and absence (versus presence) of enlarged femoral pore-bearing scales in males.

Description of holotype. Adult male, well preserved; small incision in the sternal region (portion of liver removed for genetic a sample). Body moderately large, elongate, slender; limbs well developed, moderately slender; tail autotomized, absent; margins of limbs smooth, cutaneous flaps or dermal folds absent.

Head size moderate, differentiated from neck, characterized by only slightly hypertrophied temporal and adductor musculature; snout broadly rounded in dorsal view and sharply rounded in lateral view; head width 118.8% midbody width, 85.6% head length; head length 19.0% SVL; snout length 74.2% head width, 63.6% head length; dorsal surfaces of head relatively homogeneous, with slightly to moderately pronounced concave postnasal, internasal, prefrontal, and interorbital concavities; auricular opening small, teardrop-shaped, beneath temporal swellings on either side of head; tympanum deeply sunken; orbit large; eye large, pupil vertical, margin wavy; limbs and digits relatively short; thighs moderately thicker compared to brachium; tibia length 8.2% SVL, 53.1% femur length.

Rostral size moderately large, margin oval in anterodorsal view, nearly as broad as high, sutured anterolaterally with anteriormost enlarged supralabials, projecting onto dorsal surface of head to point in line anteriormost edge of nasal; nasal surrounded by first labial, rostral, one enlarged postnasal, and two enlarged supranasals; medial supranasals separated by three moderately enlarged median scales; enlarged supranasals larger than postnasals, anteriormost supranasal largest.

Differentiated supralabials bordered dorsally by one row of slightly enlarged snout scales; differentiated infralabials bordered ventrally by undifferentiated scales or one row of slightly enlarged scales around the lower jaw; mentals and postrictals undifferentiated; gulars small, round, nonimbricate, juxtaposed; dorsal cephalic scales fairly homogeneous in size, shape, disposition, and distribution; cephalic scalation slightly convex, round to oval scales; posterior head scales granular, slightly raised into flat, plateaued dorsal surfaces.

Axilla–groin distance 50.6% SVL; dorsal body scales round, slightly raised into flat, dorsal plateaued, juxtaposed, relatively homogeneous in size; each dorsal scale surrounded by 4–6 interstitial granules, many forming a “Star of David” pattern around dorsal scale ( Siler et al. 2014b: Fig. 5); dorsals gradually transition to imbricate ventrals along lateral body surface; scales on dorsal surfaces of limbs more imbricate than dorsals; scales on dorsal surfaces of hands and feet similar to dorsal limb scales, heavily imbricate; ventral body scales flat, cycloid, strongly imbricate, much larger than lateral or dorsal body scales, relatively homogeneous in size.

Enlarged pore-bearing scales in continuous precloacal series, arranged in a widely obtuse, “V”-formation ( Fig. 2 ); patch of slightly enlarged scales posterior to precloacal series, roughly 6 or 7 scale rows in width, 3 or 4 scale rows in length, forming an oval patch just posterior to precloacal series ( Fig. 2 ).

Digits moderately expanded and covered on palmar and plantar surfaces by bowed, unnotched, undivided scansors ( Fig. 2 ); digits with minute vestiges of interdigital webbing on hands, moderate interdigital webbing on feet; subdigital scansors of fingers (left/right) I (10,9), II (11,11), III (13,13), IV (18,17), V (11,11); subdigital scansors of toes (left/right) I (10,9), II (12,11), III (16,17), IV (17,17), V (11,11); subdigital scansors of hands and feet bordered proximally (on palmar and plantar surfaces) by 1–3 slightly enlarged scales that form a nearcontinuous series with enlarged scansors; all digits clawed, but first (inner) claw greatly reduced; remaining terminal claw-bearing phalanges compressed, with moderately sized recurved claws.

Coloration of holotype in preservative. Background dorsal trunk coloration light brownish tan with intermittent to dense small dark brown speckles, continuing down to base of tail; dorsal region of head with similar color pattern, except for pronounced dark brown area above orbits; dorsal and lateral regions of limbs with same color pattern as trunk; supralabials and infralabials with similar pattern as head, but dark brown spots more diffuse; ventral side of trunk with same background coloration, dark brown speckling pattern significantly reduced; ventral side of head with sparse dark brown speckling only; ventral surfaces of the limbs, and palms of hands and feet lighter cream colored with medium to dark brown speckles scattered sparsely throughout; ventral surfaces of digits darker tan to grey with irregular, sparse dark brown speckles; skin between scansors dark brown. Coloration in life unrecorded.

Measurements and scale counts of holotype in mm. SVL 63.4; axilla–groin distance 32.1; total length N/A; tail length N/A; head length 11.8; head width 10.1; head depth 7.0; eye diameter 3.9; snout length 7.5; eye–nares distance 5.9; internarial distance 2.6; interorbital distance 7.0; midbody width 8.5; femur length 9.8; tibia length 5.2; Toe-I length 2.3; Toe-IV length 4.1; tail width 5.3; tail depth 4.7; supralabials 20; infralabials 19; circumorbitals 50; paravertebral scales 240; ventral scales 135; Finger-III scansors 13; Toe-IV scansors 17.

Distribution, ecology and natural history. Pseudogekko isapa sp. nov. is known from the islands of Tablas and Sibuyan in the Romblon Island Group ( Fig. 1 ). This species also may occur on Romblon Island itself, and eventually may be found on several of the smaller islands scattered across the province, such as Banton and Simara islands just off of the north coast of Tablas Island. Besides P. atiorum , P. isapa sp. nov. is the only other species outside of the Luzon and Mindanao PAICs; all other species are distributed across the northern, eastern, and southern islands ( Siler et al. 2014a, b; Davis et al. 2015a). Like most members of the genus, P. isapa sp. nov. appears to be primarily a forest obligate species; the holotype was collected within high quality secondary forest in Mt. Guiting- Guiting Natural Park on Sibuyan Island. This species’ poor representation in museum collections globally is a testament to the secretive nature of these species in their native habitat ( Siler et al. 2014a, b). Due to the absence of data allowing for confirmation of potential declines in population size as a result of habitat destruction, and the lack of available information about the species’ natural history, we do not find that it qualifies for formal threatened status under IUCN criteria (IUCN 2015). Therefore, we recommend that the species be considered Data Deficient at the current time, but strongly recommend that immediate and comprehensive survey efforts be made to study the health of wild populations on islands throughout the Romblon Island Group ( Fig. 1 ). With at least a very large portion of its range dominated by Mt. Guiting-Guiting Natural Park, the majority of its hypothesized distribution is very well protected.

Etymology. We derive the new species epithet from the Tagalog (Filipino) phrase isa pa, meaning “another” or “one more” in reference to our surprise at the discovery of yet another distinctive new species of Pseudogekko immediately following our review of the genus ( Siler et al. 2014a), including what we thought was a comprehensive review of the P. compresicorpus ( Siler et al. 2014b) and P. brevipes complexes ( Davis et al. 2015a). Suggested common name: Romblon Province False Gecko.

isapa sp. nov. (1 m, 1 f)

SVL 63.4, 62.1 Axilla–groin distance 32.1, 33.0 Total length –

Midbody width 8.5, 9.9 Head length 11.8, 11.7 Head width 10.1, 9.4 Head height 7.0, 7.2 Snout length 7.5, 7.2 Eye diameter 3.9, 4.0 Eye–nares distance 5.9, 6.0 Internarial distance 2.6, 2.4 Interorbital distance 7.0, 6.7 Femur length 9.8, 10.1 Tibia length 5.2, 5.5

Figures

FIGURE 1. Map of the Philippines indicating location of the Romblon Island Group. Inset shows closeup view of the Romblon Island Group and collection localities (white squares) for the new species. PAIC = Pleistocene Aggregate Island Complex, sensu Brown & Diesmos (2002).

FIGURE 2. Photographs and illustrations of preserved holotype of Pseudogekko isapa sp. nov. (PNM 9816). Photographs showing A) lateral view of head, C) ventral view of left hand, and D) ventral view of left foot; Illustrations showing B) enlarged precloacal pore-bearing scale series. Illustration by CW. Scale bars = 3 mm.