Petracola angustisoma, Echevarría & Venegas Abstract.-We, 2015

Echevarría, Lourdes Y. & Venegas Abstract. - We, Pablo J., 2015, A new elusive species of Petracola (Squamata: Gymnophthalmidae) from the Utcubamba basin in the Andes of northern Peru, Amphibian & Reptile Conservation (e 107) 9 (1), pp. 26-33 : 27-30

Petracola angustisoma sp. nov.

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Holotype: CORBIDI 00467 ( Figs. 1–3A ), adult male from vicinity of Cocachimba (06˚02’37.2’’S, 77˚53’15.8’’W; Datum WGS 84) at 1,889 m, Bongará province , Amazonas department, Peru, collected by P.J. Venegas on 24 June 2007.

Diagnosis: Petracola angustisoma differs from P. labioocularis (character states in parentheses) in having two supraoculars (three), 37 transverse dorsal scale rows (34–35), 22 transverse ventral scale rows (18–20), dorsum pale brown with seven discontinuous dark brown longitudinal stripes extending to the base of tail (brown or olive brown with a dorsolateral pale stripe on neck and body), and venter white with black semicircular marks on anterior margin of scales (grayish brown, with no pattern); precloacal pores absent (present); and by lacking supralabial-subocular fusion (present). The new species can be distinguished from P. ventrimaculata by having a gracile body (robust, Fig. 3B ), three discontinuous superciliaries (two), loreal present (usually absent), nine femoral pores per hind limb in males (2–5), and venter white with black semicircular marks on anterior margin of scales (yellow with bold black bands); from P. waka it differs in having three discontinuous superciliaries (four, usually continuous), two genials (three), and nine femoral pores per hind limb in males (5–7; Table 1).

Petracola angustisoma differs from all known species of Euspondylus , except E. spinalis , by lacking prefrontal scales and from E. spinalis by having two supraoculars (three in E. spinalis ); from Pholidobolus by having dorsals smooth and juxtaposed (imbricate, striate, or keeled in Pholidobolus ); from Proctoporus by having smooth dorsal scales (keeled in Proctoporus ); and from Riama by having smooth dorsals (smooth, striate, rugose, or keeled in Riama ).

Description of holotype: Rostral scale wider than long, taller than adjacent supralabials, in contact with frontonasal, nasals, and anteriormost supralabials. Frontonasal longer than wide, widest at level of nares, distinctly larger than frontal. Frontal approximately as long as wide, widest at anterior suture of anteriormost supraocular, barely extending between frontoparietals. Frontoparietals hexagonal, in contact medially and with supraoculars. Interparietal hexagonal. Parietals polygonal, longer than wide. Postparietals two, with posterior sutures forming a nearly straight line. Supraoculars two. Anterior supraocular larger than posterior supraocular. Superciliary series discontinuous, 2–1/2–1, the anteriormost extending onto dorsal surface of head. Nape scales immediately posterior to head scales larger than adjacent dorsals. Nasal subtriangular, pierced in center by nostril, with shallow groove extending dorsally to loreal. One loreal on each side, not in contact with supralabials. Palpebral disc transparent with minute brown flecks. Supralabials eight. Suboculars three. Postoculars two. Supratympanic temporals 3/3. Tympanum recessed, transparent. Infralabials six. Genials two, meeting at broad midventral sutures. Pregulars in somewhat regular transverse rows, anteriormost two rows larger than posterior rows. Gulars in eight rows. Gular fold distinct, concealing three rows of small scales.

Dorsals smooth, juxtaposed, rectangular, in 37 transverse rows and 19 longitudinal rows (at tenth transverse ventral scale row). Ventrals smooth, in 22 transverse and 10 longitudinal rows. Dorsals and ventrals separated by approximately three longitudinal rows of small to granular scales, which are continuous with small to granular scales at insertion of limbs. Cloacal plate with two large anterior and four large posterior scales. Tail complete. Caudal scales rectangular, smooth, glossy, in 98 transverse rows.

Forelimbs pentadactyl, with claws. Anterodorsal scales smooth, glossy, polygonal, and larger than those on posterior side. Dorsal scales on brachium much larger than ventrals. Ventral scales on brachium subgranular. Anterior scales on antebrachium polygonal, smooth, and glossy. Posteroventral scales on antebrachium roundish, smooth, and glossy. Palmar scales domed, some with central pits. Dorsal scales on finger I 2/3, II 5/5, III 8/8, IV 10/9, and V 6/6. Subdigital lamellae undivided; on finger I 5/5, II 10/9, III 13/12, IV 13/13, and V 7/8.

Scales on anterior surface of thigh polygonal, smooth, glossy, and distinctly larger than adjacent scales. Scales on anteroventral surface of thigh polygonal smooth and glossy. Femoral pores 9/9. Scales on posterior surface of thigh small, round, smooth, and glossy. Scales on dorsal surface of crus polygonal to round, subimbricate, smooth, and glossy. Scales on ventral surface of crus significantly larger than adjacent scales. Scales on dorsal surface of foot polygonal, irregularly arranged, subimbricate, and of varying sizes. Dorsal scales on toe I 3/3, II 6/6, III 9/9, IV 12/12, V 7/7, and single. Plantar scales ovoid and domed. Subdigital lamellae divided from a point halfway between base and tip to the base of toes in 7/6 rows on toe I, 12/12 on II, 17/16 on III, 20/19 on IV, 11/13 on V.

Measurements (mm) and proportions of the holotype: SVL 43.6 mm; TL 100 mm; HL 9.6; HW 6.7; ShL 5; AGD 23.4; TL/SVL 2.3; HL/SVL 0.2; HW/SVL 0.2; ShL/SVL 0.1; and AGD/SVL 0.5.

Holotype color in life: Dorsal background pale brown with seven discontinuous black longitudinal stripes on dorsum and two on flanks (continuous on neck) extending onto base of tail; dorsal and dorsolateral aspects with six longitudinal rows of dark yellow flecks extending onto tail; limbs covered by dark brown reticulations; type locality lies in the vicinity of Cocachimba and is composed of croplands with scattered large boulders and bushes, embedded in a matrix of humid montane forest. However, the forest has been almost completely removed and only some small patches of secondary forest remain close to ravines. Sympatric species of squamate reptiles are Atractus sp. , Chironius exoletus , M. boddaerti , and Stenocercus huancabambae .

Etymology: The specific epithet angustisoma is a noun (in apposition) in the nominative singular and derives from the Latin words angusti (= narrow) and soma (= body). It refers to the slender body of this species. tail with scattered dark brown marks; sides of head with longitudinal black stripes; labials and ventrolateral region of head white with black marks; sides of neck covered with black reticulations; and four faint ocelli with creamy brown center above the forelimb insertion ( Fig. 3A ). Ventral surface of body including limbs and tail white; ventral surface of head with irregular black marks on the center of each scale; ventral surface of neck with two transverse black stripes; ventral surface of trunk and tail with black semicircular marks on anterior margin of scales, arranged in transverse rows; ventral surface of forelimbs with black reticulations; ventral surface of hind limbs with roundish black marks.

Color in preservative: Similar to color in life but the dark yellow flecks on dorsum, dorsolateral region and tail are cream instead of dark yellow, and the center of the four ocelli above forelimb are cream instead of creamy brown ( Fig. 1 ).

Distribution and natural history: The new species is known only from its type locality in a montane forest of the Utcubamba basin, northern portion of Cordillera Central, Peru, at 1,889 m ( Fig. 4 ). Following the terrestrial ecoregions of the world by Olson et al. (2001), this locality lies in the Peruvian Yungas ecoregion. The holotype of P. angustisoma was found under a pile of decaying vegetation inside an abandoned house, along with a juvenile specimen of Mastigodryas boddaerti . The

Figures

Fig. 1. Petracola angustisoma sp. nov., holotype CORBIDI 00467, male, 43.6 mm SVL. Dorsal (upper) and ventral (bot- tom) views. Photographs by D. Quirola.

Fig. 2. Dorsal (A), lateral (B), and ventral (C) views of the head of Petracola angustisoma sp. nov. Holotype, CORBIDI 00467, male. Photographs by D. Quirola.

Fig. 3. Two species of Petracola in life. Holotype of P. angustisoma sp. nov. (A), and adult male of P. ventrimaculata (COR- BIDI 03630) from Laguna Norte, Cajamarca (B). Photographs by P.J. Venegas.

Fig. 4. Distribution map of species of Petracola. Petracola angustisoma sp. nov. (blue square), P. ventrimaculata (black triangles), P. labioocularis (red pentagon), P. waka (green circles).