Stenocercus omari, Venegas, Pablo J., Echevarría, Lourdes Y., García-Burneo, Karla & Koch, Claudia, 2016

Venegas, Pablo J., Echevarría, Lourdes Y., García-Burneo, Karla & Koch, Claudia, 2016, A new species of iguanid lizard, genus Stenocercus (Squamata, Iguania), from the Central Andes in Peru, Zootaxa 4205 (1) : -

Stenocercus omari sp. nov.

Figs. 1–5 , Table 1 .

Holotype. CORBIDI 0 0 577, an adult male from Abra Chanchillo (06˚47'07.00'' S, 77˚56'32.50'' W), 2786 m, Chachapoyas province, Amazonas department, Peru, collected by P. J. Venegas on 17 June 2007.

Paratypes. Peru: Amazonas department: Chachapoyas province : CORBIDI 00569–70, 00578–80 , adult females, and CORBIDI 00571–76 , adult males, collected with the holotype; Luya province : CORBIDI 11961 , adult male, and CORBIDI 11962 , adult female, from Pircopampa (06°19'32.17'' S, 78°13'1.99'' W), 2378 m, collected by K. García-Burneo on 23 September 2012; La Libertad department: Bolivar province : CORBIDI 05793–94, sub adult female and adult male, respectively, and ZFMK 90835 adult female from Bolivar (07°10'00.00'' S, 77°42'46.50'' W), 2772–3035 m, collected by A. García-Bravo and C. Koch on 21 April 2009.

Diagnosis. Stenocercus omari is distinguished from other species in the genus, except for S. amydrorhytus , S. chrysopygus , S. cupreus , S. johaberfellneri , S. latebrosus , S. melanopygus , S. modestus , S. ornatissimus , S. orientalis , and S. stigmosus by having granular scales on the posterior surfaces of thighs, a conspicuous antehumeral fold and by lacking a vertebral crest. Stenocercus omari is easily distinguished from the aforementioned species, except for S. orientalis , by the presence of prominently keeled dorsal head scales. The new species differs from S. orientalis in lacking a prominent oblique neck fold with a mite pocket under it, a distinctive character in S. orientalis , and also present in S. latebrosus and S. ornatissimus . Another important difference between the new species and S. orientalis is the presence of a longitudinal neck fold in the former, absent in S. orientalis ; such fold is also present in S. melanopygus and S. stigmosus ; however, unlike the new species described herein, both species have smooth or slightly keeled dorsal head scales. Additionally, the new species has a distinct deep postfemoral mite pocket with a posteroventrally oriented slit-like opening, whereas S. orientalis has one or more vertical folds instead ( Fig. 4 ).

The new species can be distinguished from S. orientalis in the field by color pattern. Adult males of S. omari have distinct dark triangular marks longitudinally arranged on each side of the vertebral line ( Fig. 1 A, 3A, 5A) and S. orientalis usually has a tabby dorsal pattern ( Fig. 5 D) that in some individuals is indistinct. Although males of both species share a yellow ventral coloration, males of the new species have a blue throat with dark flecks, whereas males of S. orientalis have a yellow throat with or without dark flecks and a bluish center in some specimens ( Fig. 5 E). Adult females of S. omari and S. orientalis are similar in coloration pattern; however, females of S. omari , have dorsolateral and ventrolateral light stripes on each side of the neck and females of S. orientalis have only one dorsolateral light stripe on each side of the neck ( Fig. 5 F).

Characterization. (1) Maximum SVL in males 68 mm (N =8); (2) maximum SVL in females 69 mm (N =7); (3) vertebrals 36–47; (4) paravertebrals 38–52; (5) scales around midbody 42–54; (6) supraoculars 4–7; (7) internasals 4; (8) postrostrals 2–4; (9) loreals 2–5; (10) gulars 13–25; (11) lamellae on Finger IV 18–21; (12) lamellae on Toe IV 18–29; (13) posthumeral pocket present as one vertical fold; (14) postfemoral mite pocket present as a distinct deep pocket with a posteroventrally oriented slit-like opening [Type 2 of Torres-Carvajal (2007a)]; (15) parietal eye not visible; (16) occipital scales small, keeled, subimbricate; (17) projecting angulate temporal absent; (18) supraoculars subequal in size; (19) scales in frontonasal region subimbricate, keeled; (20) short preauricular fringe present; (21) antehumeral and longitudinal neck folds present; (22) lateral nuchals half the size of dorsal nuchals; (23) posterior gulars in adults smooth, imbricate; (24) lateral scales slightly smaller than dorsal body scales; (25) vertebral crest absent; (26) dorsolateral crests absent; (27) ventrals in adults broad, lanceolate, smooth, imbricate; (28) scales on posterior surfaces of thighs granular; (29) prefemoral fold absent; (30) inguinal groove absent; (31) preanals not projecting; (32) tail not compressed laterally in adult males; (33) tail length 53–70 % of total length; (34) caudal whorls per autotomic segment three; (35) caudals not spinose; (36) dark stripe extending anterodorsally from subocular region to supraciliaries absent; (37) gular region of adult females pigmented with or without dark spots; (38) gular region of adult males pigmented with dark spots; (39) black blotch on ventral surface of neck in adult males absent; (40) thin black or dark brown midventral line absent; (41) black patch on ventral surface of thighs absent; (42) dorsal ground color brown with darker triangular marks longitudinally arranged on each side of vertebral line in females and males; (43) two xiphisternal and two postxiphisternal pairs of inscriptional ribs, the two postxiphisternal pairs of ribs short and not in contact midventrally (Pattern 1C of Torres-Carvajal, 2004a).

Description of the holotype. Male ( Figs. 1–3 ); SVL 66 mm; TL 157 mm; maximum head width 10.3 mm; head length 15.3 mm; head height 9.2 mm; occipitals, parietals, interparietals, and postparietals small, keeled, imbricate; parietal eye not visible; supraoculars in six rows, keeled, imbricate, subequal in size; canthals two; anterior most canthal in contact with the nasal; scales on frontonasal region slightly imbricate and keeled; internasals four; postrostrals four, two most lateral wider than long on each side, medial postrostrals as long as wide; supralabials five; infralabials six; loreals three; lorilabials in one row; preocular one, in contact with posterior canthal; lateral temporals keeled, imbricate; gulars in 22 rows between tympanic openings; all gulars smooth, imbricate, apical pit absent; second infralabial not in contact with second and third sublabials; mental in contact with first pair of infralabials; lateral and dorsal scales of body and neck keeled, imbricate, mucronate; lateral scales slightly smaller than dorsal body scales; scales around midbody 44; vertebrals same size as dorsals, 39 scales on vertebral row, prominent serrate vertebral crest absent; paravertebrals 45; ventrals broad, lanceolate, smooth, imbricate; preauricular fringe short, composed of three enlarged scales, all same size; antegular, gular, postauricular, oblique and supraauricular neck folds absent; longitudinal and antehumeral neck folds present; limb scales keeled, imbricate; ventral scales of hind limbs smooth and upper arms keeled; lamellae on Finger IV 18; lamellae on Toe IV 18; tail not compressed laterally; caudals keeled, imbricate, mucronate; basal subcaudals smooth, imbricate; tail length 2.4 times SVL; posthumeral pocket present as one vertical fold; postfemoral mite pocket present as a distinct deep pocket with a posteroventrally oriented slit-like opening [Type 2 of Torres- Carvajal (2007a)]; postfemoral region composed of imbricate, smooth scales that become smaller towards insertion of hind limb.

Color in life. Head and neck dark brown (almost black) with white flecks. A black vertical blotch on the antehumeral fold and a black rounded blotch on the side of the neck. Dorsum brown with dark brown triangular marks longitudinally arranged on each side of the vertebral line, and flanks yellowish cream with dark brown bands. Forelimbs dark brown with yellow flecks and hind limbs brownish yellow with dark brown transverse bands. Tail brown with dark brown marks along it. Ventrally, throat and chest sky blue with dark blue marks on the throat; ventral surface of thighs, cloacal region, and base of tail dark yellow.

Color in ethanol 70%. Head brown, white flecks turned cream. Dorsal background color of body and base of tail brownish cream with dark brown triangular marks (but lighter than in life). Sides of neck brownish cream with brown, instead of black, blotches. Flanks brownish cream flecked by brown and light cream scales, and ventrolateral region sky blue. Limbs brown with dark marks and distal portion of tail brown with light transverse bands. Ventrally the yellow surfaces turned cream.

Stenocercus omari sp. nov.

Variation. Some measurements and scutellation characters of Stenocercus omari are presented in Table 1 . Second infralabial not in contact with third sublabial in 93.8% of specimens, and first pair of postmentals in contact medially in all specimens. All male paratypes are similar to the holotype, varying only in the tone of ventral coloration; although the adult male specimen from Bolivar (CORBIDI 05794) lacks the black blotch on the sides of neck. Adult females have a cinnamon or dark brown dorsum with distinct or faint darker triangular marks longitudinally arranged on each side of the vertebral line; sides of the head and flanks brown (darker than the dorsum); supralabials white or cream, continuous with a white or cream dorsolateral stripe along the neck, becoming pale brown along the dorsum; a white or cream stripe along the edge of the jaw continues as a white ventrolateral stripe along the neck, becoming dirty cream on the flanks; flanks with or without vertical bands; dorsal surface of tail with or without transverse bands. Ventral surface dirty cream or white with or without dark flecks on the throat. Sexual dimorphism is evident in adult individuals. Females can be easily recognized by lacking white flecks on the dorsal surface of head and neck, and by having dark brown flanks (yellowish in males), and a dirty cream or white ventral coloration (throat sky blue, chest and belly yellow in males).

Distribution and natural history observations. Stenocercus omari is known from three localities along the western slope of the northern portion of the Cordillera Central at the Marañón river basin in the departments of Amazonas and La Libertad, at elevations of 2300–3035 m. According to Brack (1986) the distribution of S. omari lies inside the ecoregion of the Serrania esteparia and according to Olson et al. (2001) this species is distributed in the Peruvian Yungas ecoregion. The habitat at the type locality is a steep area located on the right side of the Marañón river with the presence of corn plantations, cattle pasture and some scattered patches of montane forest along the slope. Stenocercus omari was very common along the sides of the Leimebamba-Balsas road, a steep band covered by herbaceous vegetation with big boulders and scattered bushes. All collected individuals were found active in daylight (between 11:00 and 15:00) basking on rocks, fallen tree trunks and at the base of bushes. A gravid female (CORBIDI 00570) with SVL 65 mm collected on June contained eight yolked follicles, four in each ovary. Another gravid female (CORBIDI 11962) with SVL 69 mm collected on September contained seven well developed eggs four in the left oviduct and three in the right one, eggs ranged from 13.96–15.15 mm in length, 7.56–8.87 mm in width, and 422.33–613.98 mm 3 in volume.

Etymology. The specific epithet omari is a noun in the genitive case and is a patronym for our appreciated friend, the Ecuadorian herpetologist Omar Torres-Carvajal, who has published important contributions to the taxonomy and systematics of Neotropical lizards, especially of the genus Stenocercus .

Figures

FIGURE 1. Stenocercus omari sp. nov., holotype CORBIDI 0 0 577, male, 66 mm SVL. Dorsal (A) and ventral (B) views. Photographs by P. J. Venegas.

FIGURE 2. Dorsal (A), lateral (B), and ventral (C) views of the head of Stenocercus omari sp. nov. holotype, CORBIDI 0 0 577, male. Scale bar = 3 mm. Photographs by P. J. Venegas.

FIGURE 3. (A) Dorsolateral and (B) ventral views of the holotype of Stenocercus omari sp. nov. (CORBIDI 00577) in life. Photographs by P. J. Venegas.

FIGURE 4. The condition of the right postfemoral mite pocket in Stenocercus omari sp. nov. (CORBIDI 00575) (A) and S. orientalis (CORBIDI 00471) (B).

FIGURE 5. Two species of Stenocercus from Peru: (A) adult male of S. omari sp. nov. (CORBIDI 00573); (B) adult female of S. omari sp. nov. (CORBIDI 00570); (C) subadult female S. omari sp. nov. (CORBIDI 00580); (D) adult male of S. orientalis (CORBIDI 00471); (E) ventral view of an adult male of S. omari sp. nov. (CORBIDI 00575) (top) and an adult male of S. orientalis (CORBIDI 00583) (bottom); (F) lateral view of an adult female of S. omari sp. nov. (CORBIDI 00570) (top), and an adult female of S. orientalis (CORBIDI 00582) (bottom). Photographs by P. J. Venegas.

Tables

TABLE 1. Sexual variation in scutellation and measurements (mm) of Stenocercus omari sp. nov. Range followed by mean ± standard deviation is given for quantitative characters if applicable.

CHARACTERS	Males N = 8	Females N = 9
Scales around midbody	43 ̶48 45.25±1.98	42 ̶54 48.25±3.92 n=8
Vertebrals	37 ̶42 38.75±1.75	36 ̶47 41.75±4.27 n=8
Paravertebrals	40 ̶45 42.88±2.03	38 ̶52 44.75±4.33 n=8
Gulars	13 ̶22 20.13±3	13 ̶25 20.33±4.39
Supraoculars	5 ̶6 5.75±0.46	4 ̶7 5.78±0.97
Internasals	4	4
Subdigitals Finger IV	18 ̶20 18.88±1	18 ̶21 19.11±1.05
Subdigitals Toe IV	18 ̶28 26.63±3.5	26 ̶29 27.63±1.06 n=8
Tail length/Total length	0.53 ̶0.7 0.65±0.08 n=4	0.56 ̶0.7 0.67±0.06 n=5
Maximum SVL	68	69