Parvoscincus decipiens (Boulenger, 1894)

Linkem, Charles W. & Brown, Rafe M., 2013, Systematic revision of the Parvoscincus decipiens (Boulenger, 1894) complex of Philippine forest skinks (Squamata: Scincidae: Lygosominae) with descriptions of seven new species, Zootaxa 3700 (4), pp. 501-533 : 523-525

Redescription of Parvoscincus decipiens (Boulenger, 1894)

Figs. 2 ; 3F; 4A, B, C; 5A, B

Lygosoma decipiens: Boulenger, 1894: 734

Lygosoma decipiens: Smith, 1937: 220

Sphenomorphus decipiens: Taylor, 1922 a

Lygosoma (Homolepida) moellendorffi: Boettger, 1897

Sphenomorphus moellendorffi: Taylor, 1922 a

Sphenomorphus curtirostris: Taylor, 1915

Otosaurus curtirostris: Smith, 1937

Lygosoma (Sphenomorphus) curtirostris: Brown and Alcala, 1970

Sphenomorphus decipiens: Brown and Alcala, 1980: 186 (part)

Parvoscincus decipiens: Linkem, Diesmos, Brown, 2011

Parvoscincus decipiens: Brown, Siler, Oliveros, Welton, Rock, Swab , van Weerd, van Beijnen, Jose, Rodriguez, Jose, Diesmos, 2013

Syntypes. BMNH 1946.8.16.95–96

Referred specimens. KU 326592–99, KU 326601, KU 326603, KU 326606, KU 326608–11.

Genetic data. GenBank KF425395 – KF425444 .

Diagnosis. Parvoscincus decipiens can be diagnosed by the following combination of characters: (1) A small body size (SVL at maturity 35.02–40.62 mm); (2) MBSR = 30–34; (3) PV = 54–63; (4) dorsal scales non-striated without apical pits; (5) apical pits on hind limbs, variably present on forelimbs; (6) four enlarged supraoculars; (7) anterior loreal single; (8) three preoculars; (9) and 14–18 Toe IV SDL.

Parvoscincus decipiens is the sister species to P. abstrusus sp. nov. and closely related to P. jimmymcguirei sp. nov., P. arvindiesmosi sp. nov., and P. agtorum sp. nov. ( Fig. 2 ). Parvoscincus decipiens can be distinguished from P. jimmymcguirei sp. nov. by not having apical pits on the dorsum or forelimbs (vs. having apical pits on dorsum and forelimbs); by having white labials and throat (vs. dark brown mottling on labials and throat); having a thin dorsolateral band with a solid tan line dorsally (vs. broad dorsolateral band).

Parvoscincus decipiens can be distinguished from P. arvindiesmosi sp. nov. by having a wider rostrum ( IND / Rost> 0.50 vs. <0.50); lacking apical pits on the dorsum and forelimbs (vs. apical pits present on forelimbs and dorsum); dorsum brown without dark brown spots laterally (vs. dark brown spots extending dorsally from the dorsolateral line); dorsolateral line thin and flanks light tan (vs. dorsolateral line broad, dark brown, and extending ventrally to mid-flank).

Parvoscincus decipiens can be distinguished from P. abstrusus sp. nov. by lacking apical pits on dorsum and forelimbs (vs. apical pits weak or absent on dorsum and present on forelimbs); having a single anterior loreal (vs. single or divided anterior loreal); males and females having white throat (vs. males with black throat and females with white throat); dorsolateral band thin with light tan line dorsally (vs. dorsolateral band thin, broken, and occasionally bordered by light tan dorsally).

Parvoscincus decipiens can be diagnosed from P. agtorum sp. nov. by the smaller body size (35.02–40.62 vs. 44.91 mm); fewer paravertebral scales (54–63 vs. 71); fewer midbody scale row scales (30–34 vs. 39); light-tan dorsal coloration (vs. dark brown dorsal coloration); by the absence of a brown incomplete gular collar; and by the absence of a white line between the eye and ear.

Redescription of species based on syntypes and referenced specimens. A small-sized Parvoscincus , SVL 35–41 mm, with clawed, pentadactyl limbs. Snout rounded in lateral profile with lower jaw slightly sunk; rostral wide forming an oval dorsal margin with the nasals and frontonasal scale; frontonasal wider than long, in contact with nasals, rostral, anterior loreals, and prefrontal scales; prefrontals in broad medial contact, left overlapping right, in contact with anterior and posterior loreals, frontal, frontonasal, and 1st supraciliary; frontal slightly longer than wide, in contact with two supraoculars, posterior apex acutely rounded; four enlarged supraoculars, 1st largest, 2nd widest; frontoparietals fused, in contact with three supraoculars; interparietal kite-shaped with posterior axis 6x longer than anterior axis, interparietal eye visible, positioned near posterior margin; parietals in broad overlap, left overlapping right, in contact with postsupraoculars, primary and secondary temporals; nuchals same size as dorsals, not obliquely enlarged.

Nasal pierced in center by large naris, surrounded anteriorly by rostral, dorsally by frontonasal, posteriorly by anterior loreal, and ventrally by 1st supralabial, in point contact with 2nd supralabial; single anterior loreal, rectangular, taller than wide, posterior loreal wider and taller than anterior; preoculars two; seven supralabials, 4th widest and under center of eye; supraciliaries nine, anterior three and posterior two larger than rest of series; 10 ciliaries; lower eyelid scaly and transparent, lacking non-scaled “window;” suboculars eight, largest anteriorly; primary temporals one, secondary temporals three, lower overlapping upper; ear large, round, and moderately sunk.

Infralabials seven, decreasing in size posteriorly in series; mental large, forming a straight suture with a single large postmental and first infralabials; postmental contacts anterior two infralabials; chin scales increasing in number posteriorly (one, three, five) and then blending into size and shape of gular scales; gular scales slightly smaller than ventrals.

Body not elongate (AGD/SVL <0.5), cylindrical, with 31 to 34 equal-sized midbody scales, limbs overlapping when adpressed; lateral body scales with two or three rows of apical pits; paravertebral scales 58–63, imbricate, without apical pits. Tail elongate, slightly longer than body and cylindrical at base, slightly thicker dorsally than ventrally; subcaudal scales nondifferentiated.

Forelimbs smaller than hind limbs, pentadactyl; dorsal forelimb scales slightly smaller than body scale, ventral forelimb scales much smaller than ventral scales, dorsal and ventral forelimb scales imbricate, occasionally with rows of apical pits; multiple rows of dorsal scales on digits. Relative digit length IV> III> II> V> I. Palmar scales irregular, raised, forming ventral protrusions from palmar surface; large set of five scales on distolateral edge of Digit V to the wrist, largest scale at wrist.

Hind limbs small, pentadactyl; dorsal and ventral hind limb scales smaller than body scales; dorsal scales covered in apical pits, ventral scales with single row of apical pits; multiple scale rows on dorsal side of digits. Lamellae slightly keeled. Relative digit length: IV> III> V> II> I. Plantar scales irregular, slightly raised; four large, ventrally pointed scales along ankle/plantar margin; ventrally raised scales along distolateral edge of Digit V to ankle, increasing in size toward ankle.

Precloacal region with series of enlarged scales between pelvic region and cloaca, more elongate than ventral scales; medial precloacal scales larger, overlapping lateral scales.

Coloration. Dorsal ground color brown throughout; a series of small dark brown dorsovertebral spots from the nuchals to the base of the tail. Dorsolateral line broad near head, from posterior midline of eye to nuchal region tapering irregularly on ventral margin to forelimb and blending in midbody; bordered ventrally by narrow white line; bordered anteriorly by a tan line half a scale wide that continues down the entire length of the body and anterior of tail. Anterior to the forelimb and ventral to the dorsolateral line is some brown ticking that continues around the gular region. The ground color of the gular and ventral region is cream color. The ventrum from the gular region posteriorly and the ventral side of limbs are all cream without any markings. Distal portion of ventral tail has some brown ticking. Dorsal aspect of limbs light brown with posterior portion having some dark brown reticulation. Coloration in life does not differ substantially from that in preservative.

Distribution ( Fig. 1 ). This species occurs in abundance in the Sierra Madre Mountain Range of northeast Luzon in the Provinces of Isabela and Cagayan (Brown et al. 2013). This species occurs in sympatry with Parvoscincus jimmymcguirei sp. nov.

Natural history. This species is found in mid-montane forest in leaf litter and under logs.

Etymology. The specific epithet was presumably derived, in the nominative case, from the Latin decipio, meaning “deceiving.”

Note on the taxonomic status of Lygosoma moellendorfi Boettger, 1897 , Sphenomorphus curtirostris Taylor, 1915 , and Parvoscincus kitangladensis (Brown, 1995) . Although previous workers (Brown & Alcala 1980) have applied the name Parvoscincus decipiens to selected populations from the southern Philippines, our comprehensive phylogenetic work (Linkem et al. 2011; unpublished data) plus the results of this study convince us that all Mindanao populations previously identified as P. decipiens are most likely best referred to the species P. kitangladensis (Brown 1995) . Sphenomorphus curtirostris was described by Taylor (1915) as a species found on Mindanao Island, and also consisted of samples from Mt. Makiling. Taylor’s concept of S. curtirostris appears to us to have been based on a combination of populations now known to consist of at least two species ( P. kitangladensis and P. abstrusus sp. nov.). Since the type is from Mindanao Island, the name should be applied to Mindanao species, which we have re-assigned to P. kitangladensis . This presents a dilemma in that P. curtirostris is the older name and therefore would be the valid name for species currently considered P. kitangladensis . The descriptions of these two species do not completely overlap and with relatively poor sampling of populations from throughout eastern Mindanao it is difficult for us to determine whether P. kitangladensis and P. curtirostris are conspecific. Given the larger size of P. kitangladensis (SVL 50–60 mm) it is possible that P. kitangladensis is separate from P. curtirostris and that Mindanao specimens previously assigned to P. decipiens should be P. curtirostris and the name should be re-elevated from synonymy. We prefer at this time to leave P. curtirostris as a synonym of P. decipiens and to refer to all Mindanao specimens as P. kitangladensis until a more thorough sampling of populations with tissue samples can be made.

Lygosoma moellendorfi was described from Tablas Island and later synonymized with P. decipiens by Brown and Alcala (1980). There are seven specimens from Tablas Island (CAS 137285–7, CAS 137298–301, CAS 186119), three of which have been examined by us. These three specimens differ morphologically from all of the species recognized here, and probably represent a distinct lineage. The Tablas population has PV 75–82, MBSR 39–41, and Toe IV SDL 17–19, which are values slightly higher than all other species examined here. A more thorough examination of the Tablas Island samples and incorporation of molecular data may allow for the elevation of this population from the synonymy of P. decipiens . However, we prefer not to take taxonomic action until genetic samples are available to allow for the confident determination of the Tablas Island population’s affinities

Figures

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

FIGURE 2. Partitioned Bayesian majority rule consensus estimate of molecular phylogeny from the ND 2 data of Parvoscincus. Populations within the P. decipiens complex are genetically unique and are diagnosed as new species based on morphological differences. Black circles label nodes with posterior probabilities above 0.95.