Enyalioides rudolfarndti, Venegas, Pablo J., Duran, Vilma, Landauro, Caroll Z. & Lujan, Lesly, 2011

Venegas, Pablo J., Duran, Vilma, Landauro, Caroll Z. & Lujan, Lesly, 2011, A distinctive new species of wood lizard (Hoplocercinae, Enyalioides) from the Yanachaga Chemillen National Park in central Peru, Zootaxa 3109, pp. 39-48 : 40-45

Enyalioides rudolfarndti sp. nov.

( Figs. 1–3 )

Proposed standard English name: throat-sliced wood lizard

Proposed standard Spanish name: lagartija de palo de garganta cortada

Holotype. CORBIDI 0 7209 ( Figs. 1–2 ), an adult male from the Pan de Azucar trail near the Puesto de Control Huampal in the YCNP (10°11´03´´ S 75°34´27´´ W; WGS 84) at 1050 m.a.s.l., collected on 16.VIII.2010, Provincia de Oxapampa, Región de Pasco, Peru, by P. J. Venegas.

Paratypes. CORBIDI 0 7210 and 0 7213, an adult female and a juvenile, respectively, collected with the holotype by P. J. Venegas, V. Duran, C. Z. Landauro, and L. Lujan. CORBIDI 0 7212, an adult male from the same location of the holotype but taken on 19.VIII.2010 by P. J. Venegas.

Diagnosis. Enyalioides rudolfarndti can be easily distinguished from other species of Enyalioides from the Amazon basin by the combination of the following characters: (1) scales posterior to the superciliaries enlarged (relative to adjacent scales), forming a well defined longitudinal row of distinctly raised scales across the lateral edge of the head in juveniles and adults of both sexes; (2) 30 or fewer longitudinal rows of dorsals in a transverse line between the dorsolateral crests at midbody; (3) a distinct orange round blotch on the antehumeral region in adult males; (4) ventral scales strongly keeled; (5) caudal scales heterogeneous in size on each autotomic segment. The orange round blotch on the antehumeral region in adult males of Enyalioides rudolfarndti is present also in some male individuals of E. palpebralis ( Fig. 4 ). Furthermore, the new species also shares with E. palpebralis the presence of enlarged scales posterior to the superciliaries and the presence of strongly keeled ventral scales; however, the latter species can be easily distinguished from E. rudolfarndti by having a superciliary triangular flap that projects posterolaterally over each eye. In addition, E. palpebralis is the only species that has (most specimens) a discontinuous vertebral crest, having a small gap on the neck, and lacks femoral pores ( Torres-Carvajal et al. 2011). Enyalioides cofanorum and E. microlepis share with the new species the presence of strongly keeled ventral scales and caudal scales of heterogeneous size on each autotomic segment. However, E. cofanorum differs from E. rudolfarndti (characters in parentheses) by having with more than 33 dorsal scales in a transverse line between the dorsolateral crests at midbody (30 or fewer) and scattered, projecting, large dorsal scales (absent). Enyalioides microlepis differs from E. rudolfarndti by having more than 40 dorsal scales in a transverse line between the dorsolateral crest at midbody (30 or fewer dorsal scales), and a low vertebral crest (high). In addition, adult males of E. cofanorum and E. microlepis have a black patch that covering the gular region (absent).

Description of holotype. Male ( Figs. 1–2 ); SVL= 116 mm; TL = 191 mm; maximum head width = 23.2 mm; head length = 31.6 mm; head height = 23 mm; dorsal head scales including parietal region multicarinate; scales on lateral edge of head just posterior to superciliaries enlarged, forming a well defined longitudinal row of 7 (left) or 6 (right) distinctly raised scales; temporal scales small, conical, juxtaposed, nearly homogeneous in size; 1 large, pretympanic conical scale in anterodorsal margin of the tympanum; superciliaries 17; canthals 4; postrostrals 4; left supralabials 13 if counted to a point right below middle of eye, and 16 if counted to commisure of mouth (13 and 16 on right side, respectively); rostral (2.92 × 1.16 mm) about twice as wide as the adjacent supralabials; single longitudinal row of lorilabials between suboculars and supralabials at level of middle of the eye, longitudinal rows of lorilabials anterior to this point 2–3; loreal region broken into small, smooth, and juxtaposed scales; nasal at the level of supralabial IV; left infralabials 10 if counted to a point right below middle of eye, and 14 if counted to commisure of mouth (11 and 16 on right side, respectively); mental (2.77 × 1.39 mm) wider and higher than the adjacent infralabials; postmentals 2; gulars ventrally projected; gular fold weakly defined, complete midventrally; neck with only 2 distinct oblique folds.

Vertebral crest strongly projecting, decreasing in size posteriorly, with vertebrals on the neck at least four times higher than vertebrals between the hind limbs; crest bifurcates posteriorly at base of the tail and extends onto the tail for less than one-third of its length; flanks between forelimbs and hind limbs with dorsolateral and ventrolateral folds, as well as some oblique folds; scales on dorsolateral folds slightly larger than on the adjacent scales and forming a distinct row of raised scales; dorsal scales between dorsolateral fold and vertebral crest heterogeneous in size with small and large, strongly keeled, and imbricate scales; scales on flanks (i.e., ventral to dorsolateral fold) heterogeneous in size with some scales similar in size to dorsals surrounded by minute keeled scales, and some scattered enlarged scales with projecting keels that are two to three times larger than the adjacent scales on the near hind limb insertion; ventral scales imbricate, strongly keeled, rectangular, without a posterolateral mucron; ventrals more than twice the size of the dorsals.

Limb scales keeled dorsally and ventrally; thigh scales homogeneous in size dorsally and heterogeneous in size posteriorly, with most scales less than half of the size of those scales on the anterior and ventral aspects; subdigitals on Finger IV 19; subdigitals on Toe IV 25; femoral pore on each side 1; tail compressed and gradually decreasing in height towards tip; caudal scales strongly keeled and imbricate, increasing in size posteriorly on lateral and dorsal aspects of each autotomic segment; ventral caudals larger than dorsal caudals, with individual autotomic segments being 3 scales long ventrally and 5 scales long dorsally.

Color in life of holotype ( Figs. 1–2 ): scales on dorsal and lateral surface of head, including labials, rostral, and mental, green; gulars greenish white; skin between gulars black; small dark gray and diffuse gular patch immediately anterior to gular fold; one big orange blotch on each side of the neck, extending posteriorly onto the antehumeral region and ventrally near the dark gular patch; dorsal background green; pale gray round blotches covering dorsolateral region from the neck to base of the tail; fine black reticulation on dorsal aspect of the body, limbs, flanks, and the proximal portion of the tail; ventrolateral region sky blue; ventral surface of body, limbs, and tail white; lateral borders of venter and ventral surface of thighs and shanks sky blue; the iris is gray with a fine brown radiation; pupil round with a white margin.

Color in ethanol after 10 months of preservation: dorsal background pale turquoise, gulars grayish turquoise; antehumeral blotch yellow; reticulation on the dorsal aspect of body, limbs, and base of the tail dark gray; gray blotches on dorsolateral region absent; ventral surface of body, limbs, and tail dark cream.

Variation. Meristic and morphometric characters of Enyalioides rudolfarndti are summarized in Table 1. In life, the single adult male paratype CORBIDI 0 7212 ( Fig. 3 A–B) has the same background coloration as the holotype but has the dorsum, flanks, dorsal surface of limbs and tail covered by black flecks and not by a fine black reticulation as on the holotype.

Characters

Dorsal in transverse row between dorsolateral crests at midbody 27–30, 28.25 ± 1.5 Ventrals in transverse row at midbody 28–32, 30.25 ± 3.69 Vertebrals from occiput to base of tail 42–47, 45.5 ± 2.38 Gulars 33–36, 34.5 ± 1.29 Infralabials 11, 11

Supralabials 11–14, 12.5 ± 1.29 Canthals 3–4, 3.75 Superciliaries 14–18, 15.25 ± 1.89 Transverse rows of ventrals between fore and hind limb 35–38, 36.75 ± 1.5 Subdigitals fingers IV 19–23, 20 ± 2 Subdigitals toe IV 25–28, 26.5 ± 1.29 Femoral pores 1, 1

Head length/Head width 1.30–1.43, 1.35 ± 0.06 Fore limb length/SVL 0.43–0.56, 0.50 ± 0.05 Hind limb length/SVL 0.76–0.87, 0.80 ± 0.05 Tail length/Total length 0.60–1.49, 0.83 ± 0.44

In life, the single female paratype CORBIDI 0 7210 ( Fig. 3 C–D) has the head mossy green with black markings including flecks on the dorsal surface of head; a narrow stripe posterior to the superciliaries extends along the lateral edge of the skull roof; a broad postocular stripe extends to the commisure of the mouth and the anterior border of the tympanum, and an infraorbital stripe is present between the eyes and the labials; the dorsal surface of the neck has a white blotch on each side behind the tympanum, followed by a longitudinal pale stripe that extends to the scapular region; the gular region is dark gray, darker on the gular fold, with dark brown spots; the dorsal background is mossy green with transverse diffuse black bars on the body, limbs, and tail; the ventral surface of the body, limbs and tail is grayish white with black spots in the lateral borders of the belly, ventral surface of the limbs, and the tail; iris gray with a brown reticulation. The vertebral crest and the enlarged and raised scales posterior to the superciliaries are high as in the males.

In life, the juvenile paratype CORBIDI 0 7213 ( Fig. 3 E–F) has the head copper with black flecks on the dorsal surface and a broad dark brown subocular stripe; the dorsal background is dark brown with copper transverse bars on the body, limbs, and tail; the belly is copper with scattered dark copper and brown spots; the ventral surfaces of the limbs and the tail are dark brown with copper spots; the gular region is copper and darker than the belly, with some white spots on the ventral border of the snout; the iris is reddish brown and the pupil is round with a golden margin.

Distribution and natural history. Enyalioides rudolfarndti is known only from the type locality in the Región de Pasco, at an elevation of 1050 m.a.s.l., on the upper Amazon basin of central Peru ( Fig. 5 ). This new species inhabit the premontane forest of the Río Huancabamba canyon that lies within the YCNP in the Pasco region ( Fig. 6 ). All individuals of E. rudolfarndti were collected at night sleeping on horizontal stems of bushes up to 1.50 m above the ground. Sympatric species of reptiles collected with Enyalioides rudolfarndti were Cercosaura argulus, Clelia clelia, Dipsas catesbyi, D. indica, D. schunkii, Micrurus annellatus, Oxyrhopus melanogenys, and Stenocercus torquatus .

Etymology. The specific name is a patronym for Dr. Rudolf G. Arndt of Pomona, New Jersey, USA, in recognition of his financial support for the improvement of the herpetological collection of CORBIDI through the BIOPAT-Programme.

Remarks. Although Enyalioides rudolfarndti and a new species of Euspondylus are the only new species of reptile discovered in the Cordillera Yanachaga in the two last decades, the recent taxonomic work on amphibians and herpetological inventories in this region has resulted in the description of 27 new species of amphibians, of which 10 were discovered inside YCNP ( Duellman et al. 2006; Lehr & Trueb 2007; Lehr et al. 2007; Chaparro et al. 2008; Boano et al. 2008; Duellman & Hedges 2008; Duellman & Chaparro 2008). The lack of new reptiles taxa discoveries in this region probably relates to an absence of taxonomic work in this group in general. Moreover, due to its complex topography, the Cordillera Yanachaga has not been adequately sampled and some areas, such as YCNP, have been only slightly explored. However, in a rapid biological inventory carried out in the northern portion of YCNP during August 2010, we collected the new lizard species described herein; a new species of gymnophthalmid lizard, genus Euspondylus ( Chavez et al. 2011) ; two new species of strabomantid frogs, genus Phrynopus ; and one new species of casqued tree frog, genus Osteocephalus , all of which are now being described. These findings highlight the importance of collecting in poorly explored areas of Peru, a country that awaits a large number of discoveries in herpetological terms.

Figures

FIGURE 1. Dorsolateral view of the holotype of Enyalioides rudolfarndti sp. n. (CORBIDI 0 7209, adult male, SVL 116 mm). Photograph by P. J. Venegas.

FIGURE 2. Close-up of head of Enyalioides rudolfarndti sp. n. (CORBIDI 07209) showing the orange anthehumeral blotch. Photograph by P. J. Venegas.

FIGURE 3. Dorsolateral and ventral views of the paratypes of Enyalioides rudolfarndti sp. n. Adult male (A, B, CORBIDI 07212), adult female (C, D, CORBIDI 07210), and juvenile (E, F, CORBIDI 07213). Photographs by P. J. Venegas.

FIGURE 4. Close-up of head of Enyalioides palpebralis (CORBIDI 0 8347, adult male, SVL 112 mm) showing the orange antehumeral blotch. Photograph by G. Chávez.

FIGURE 5. Distribution of Enyalioides rudolfarndti sp. nov. in Peru. The red triangle indicates the type locality, the only locality where the species is known to date. White circles are important cities for reference.

FIGURE 6. Habitat at the type locality of Enyalioides rudolfarndti sp. nov. on August of 2010. Photograph by P. J. Venegas.