Stenocercus dracopennatus, Venegas & García-Ayachi & Chávez-Arribasplata & Chávez & Wong & García-Bravo, 2020

Venegas, Pablo J., Garcia-Ayachi, Luis A., Chavez-Arribasplata, Juan C., Chavez, German, Wong, Ivan & Garcia-Bravo, Antonio, 2020, Four new species of Stenocercus Dumeril & Bibron, 1837 (Squamata, Iguania) from the Department of Amazonas in northeastern Peru, Evolutionary Systematics 4 (2), pp. 79-108 : 79

Stenocercus dracopennatus sp. nov. Figs 6 , 7 , 8 , 9

Type material.

Holotype:

PERU • ♂, adult; Amazonas Department, Bongará Province, Yambrasbamba District, Yambrasbamba; 5°43.01'S, 77°58.61'W; 2370 m a.s.l.; 07 Sept. 2017; P.J. Venegas leg.; CORBIDI 18875.

Paratypes:

PERU • 2 ♂, adult and juvenile collected with the holotype; CORBIDI 18868,18876.

Diagnosis.

Stenocercus dracopennatus sp. nov. differs from all species of Stenocercus , except for S. aculeatus , S. angulifer , S. prionotus , and S. scapularis , by having: (1) projecting angulate temporals, (2) laterally oriented nostrils, (3) dorsolateral crest (distinct on second half of body and base of tail in S. prionotus ), (4) dorsal and lateral scales of body similar in size, (5) strongly keeled ventrals, and (6) scales on posterior surface of thighs keeled and imbricate.

However, S. dracopennatus sp. nov. can also be easily distinguished from S. prionotus (state of characters in parentheses) by having a low-lying vertebral crest (high and projected, Figs 4E , 9A ) and postfemoral mite pocket as a slit-like opening (absent). Furthermore, S. dracopennatus sp. nov. differs from S. scapularis (state of characters in parentheses) by having a thin and inconspicuous subocular stripe (conspicuous and broad subocular stripe, Fig. 16 ), smooth infralabials and sublabials (keeled), a black patch covering the ventral surface of neck (absent), and 38 to 40 vertebrals (43 to 53).

Stenocercus dracopennatus sp. nov. can be readily distinguished from S. angulifer and S. aculeatus by having two canthals and a black patch covering the ventral surface of the neck (one canthal and a black patch extensively covering most of the gular region in the last two species, see Figs 4D , 7B, D ). Additionally, Stenocercus dracopennatus sp. nov. differs from S. aculeatus (state of characters in parentheses) by having a longer snout (shorter, Fig. 8A, B ), a low-lying vertebral crest (distinctly higher, Fig. 9A, B ), a deeper posthumeral mite pocket (less deep, Fig. 8C, D ), and cycloidal, smooth or feebly keeled dorsal scales at midbody between the dorsolateral crests with or without minute mucronations (lanceolate, strongly keeled and mucronate, Fig. 9C-F ).

Definition.

(1) Maximum SVL in males 89 mm (n = 3); (2) SVL in females unknown; (3) vertebrals 38-40; (4) paravertebrals 53-57; (5) scales around midbody 39-45; (6) supraoculars 4; (7) internasals 4-5; (8) postrostrals 2-5; (9) loreals 4-5; (10) gulars 19-20; (11) subdigitals on Finger IV 19-21; (12) subdigitals on Toe IV 26-28; (13) posthumeral mite pocket present as a deep depression with a narrow opening [Type 3 of Torres-Carvajal (2007b)]; (14) postfemoral mite pocket present as a distinct pocket with a posteroventrally oriented slit-like opening [Type 2 of Torres-Carvajal (2007b)]; (15) parietal eye not visible through interparietal cornea in any specimens (n = 3); (16) scales on occipitoparietal region large, feebly keeled or wrinkled, juxtaposed; (17) projecting angulate temporals present, two; (18) row of enlarged supraoculars occupying most of supraocular region present; (19) scales on frontonasal region feebly keeled, juxtaposed; (20) preauricular fringe present, distinct; (21) neck folds absent; (22) lateral and dorsal nuchals similar in size; (23) posterior gulars lanceolate, projected posteriorly, strongly keeled, mucronate and conspicuously imbricate; (24) lateral and dorsal body scales similar in size; (25) vertebrals larger than adjacent paravertebrals, forming a low vertebral crest; (26) dorsolateral crest present; (27) ventrals strongly keeled, imbricate, mucronate; (28) scales on posterior surfaces of thighs keeled, imbricate, mucronate; (29) inguinal granular pocket absent; (30) inguinal groove absent; (31) preanals projected; (32) tail compressed laterally in adult males; (33) tail length 68-72% of total length; (34) caudal whorls per autotomic segment three; (35) caudals not spinose; (36) dark brown stripe extending anterodorsally from subocular region to supraciliaries present, present only in juveniles; (37) dark patch extensively covering gular region of females unknown; (38) dark patch covering gular region in adult males absent; (39) black patch on ventral surface of neck in adult males present; (40) dark midventral longitudinal mark such as faint line, conspicuous stripe, or extensive patch in adult males absent; (41) dark patches on ventral surface of thighs in adult males absent; (42) two xiphisternal and three postxiphisternal pairs of inscriptional ribs fused medially, forming three chevrons (Pattern 6A of Torres-Carvajal 2004).

Description of the holotype.

Male (Fig. 6 ); SVL 79 mm; TL 210 mm; maximum head width 16.4 mm; head length 20.5 mm; head height 13.5 mm; parietals, interparietals and postparietals large; interparietals keeled, parietals and postparietals barely rugose, juxtaposed; occipital small, barely wrinkled; parietal eye not visible; supraoculars in four rows, keeled, slightly imbricate, subequal in size; canthals two; canthal not in contact with the nasal; scales on frontonasal region slightly imbricate, keeled; internasals five; postrostrals five, the three on the middle longer than wide and one third longer than postrostrals on the sides; supralabials five; infralabials seven; loreals five; lorilabials in one row; preocular one, in contact with second canthal; lateral temporals keeled, some of these with a minute mucron, imbricate; gulars in 19 rows between tympanic openings; all gulars keeled, mucronate, imbricate, posteriorly projected, apical pit absent; second infralabial in contact with first to third sublabials; mental in contact with first pair of infralabials; lateral and dorsal scales of body and neck keeled, imbricate, mucronate; lateral and dorsal body scales similar in size; scales around midbody 39; vertebrals larger than dorsals, 38 scales on vertebral row, low serrate vertebral crest present; paravertebrals 53; ventrals broad, rhomboidal, strongly keeled, mucronate, imbricate; preauricular fringe short, indistinct, composed of six small scales, all similar in size; antegular, gular, postauricular, oblique, supraauricular, longitudinal and antehumeral neck folds absent; limb scales strongly keeled, imbricate, mucronate; ventral scales of hindlimbs and upper arms strongly keeled and mucronate; lamellae on Finger IV 21; lamellae on Toe IV 28; tail compressed laterally; caudals keeled, imbricate, mucronate but without projected spines; basal subcaudals strongly keeled, imbricate; tail length 2.6 times SVL; posthumeral mite pocket present as a deep depression with a narrow opening; postfemoral mite pocket present as a distinct deep pocket with a curved slit-like opening bordering the thigh insertion; postfemoral region composed of imbricate, keeled scales.

Coloration in life

(Fig. 7A, B ). Dorsal surface of the body is dusty brown with a greenish yellow hue on the pelvic region and tail; the vertebral and dorsolateral crests are yellowish with faint gray vertebral chevrons on the back, the posterior margin of each chevron is yellowish as well; antehumeral region with a dark brown vertical stripe with the anterior margin yellowish; flanks with diagonal rows of yellowish dots; limbs and proximal half of tail with transverse yellowish stripes; ventrolateral region turquoise; sides of head sepia and ocular region black. Ventrally, gular region sepia, ventral surface of neck covered by a black patch; chest, pelvic region and ventral surface of hindlimbs, and base of tail dirty cream with the sides of belly turquoise; proximal half of the tail is also dirty cream with transverse paler bands. The iris is dark brown.

Coloration in preservative

(Fig. 6D, E ). Similar to the coloration in life however the dorsal background and marks are paler than in life with a long patch of depigmentation on the back. The ventral surface turns bluish gray with scattered pale blotches on the belly.

Intraspecific variation.

Measurements and scutellation characters of Stenocercus dracopennatus sp. nov. are presented in Table 1 . The first pair of postmentals are not in contact medially in one specimen (CORBIDI 18868). The adult male paratype is larger than the holotype with 89 mm of SVL and its dorsal coloration is pale compared to the holotype, lacking the dark dorsal chevrons present in the holotype (Fig. 7C ). The ventral pattern is identical to the holotype (Fig. 7D ). The second paratype is a juvenile male (CORBIDI 18876) with the dorsum cinnamon and with the vertebral chevrons more contrasting than in the holotype; a distinct dark brown stripe extending anterodorsally from subocular region to supraciliaries; dots on the flanks of this juvenile specimen are yellow with the dots on the axillary region whitish and lacking the turquoise hue of the adult specimens (Fig. 7E ). Ventrally, the gular region is dark sepia and the rest of body whitish cream with the sides of belly dark gray and not turquoise like in the adult (Fig. 7F ). Females are unknown.

Distribution and natural history observations.

Stenocercus dracopennatus sp. nov. is only known from the type locality, a summit near Yambrasbamba village at 2370 m elevation, located on the eastern slope of the Cordillera de Colán, at the Río Chiriaco basin, Department of Amazonas, Peru (Fig. 5 ). According to Peñaherrera del Aguila (1989) and Olson et al. (2001), the distribution of this new species occurs within the Yungas and Peruvian Yungas ecoregions, respectively. The new species inhabits a mountain top covered by a dwarf montane forest full of terrestrial and arboreal bromeliads on a white sand soil. Six individuals were observed basking on a sunny morning, between 1000 and 1100 hours, on the sand and on fallen branches and running to find refuge in patches of terrestrial bromeliads and long grasses. No other reptile species were found in sympatry with S. dracopennatus sp. nov.

Etymology.

The specific epithet " dracopennatus " is a noun derived from two words in Latin, " draco " that means dragon, the mythological being, and " pennatus " that means feathered. The specific name is a noun in apposition and refers to the similarity between lizards and dragons, which in both Western and Chinese cultures are beings similar to reptiles like crocodiles or serpents. Moreover, due to the big scales of this new species that give it the appearance of being covered by feathers, we decided to name S. dracopennatus sp. nov. for its resemblance to an imaginary feathered dragon.

Figures

Figure 4. Dorsolateral and ventral views of adult males of three species of Stenocercus: (A, B) S. huancabambae, (C, D) S. aculeatus, (E, F) S. prionotus from northern-central Peru, and (G, H) S. prionotus from southern Peru. Photographs by: (A - D) Pablo J. Venegas, (E) Andy Barboza, (F) Diego Vasquez, and (G, H) German Chavez.

Figure 5. Distribution map of S. catherineae sp. nov. (red triangles), S. dracopennatus sp. nov. (yellow star), and S. philmayi sp. nov. (blue squares), and the similar species: S. aculeatus (fuchsia diamonds), S. angulifer (blue diamonds), S. huancabambae (orange diamonds), S. prionotus (turquoise diamonds), and S. scapularis (red diamonds). Symbols with a dot in the middle correspond to type localities. White circles with a dot are important cities for reference.

Figure 6. Stenocercus dracopennatus sp. nov. preserved holotype, adult male, SVL 79 mm (CORBIDI 18875): dorsal (A), lateral (B), and ventral (C) views of the head; dorsal (D) and ventral (E) views of the entire specimen. Photographs by Luis A. Garcia-Ayachi. Scale bars: 10 mm.

Figure 7. Dorsolateral and ventral views of Stenocercus dracopennatus sp. nov. in life: (A, B) holotype, adult male, SVL 79 mm (CORBIDI 18875); (C, D) adult male, SVL 88 mm (CORBIDI 18868); (E, F) juvenile male, SVL 56 mm (CORBIDI 18876). Photographs by Pablo J. Venegas.

Figure 8. Lateral view of head and posthumeral mite pockets of adult male Stenocercus for comparison: (A) S. dracopennatus sp. nov. (CORBIDI 18868), (B) S. aculeatus (CORBIDI 11483), (C) S. dracopennatus sp. nov. (CORBIDI 18875), and (D) S. aculeatus (CORBIDI 1712). Photographs by Luis A. Garcia-Ayachi. Scale bars: 5 mm.

Figure 9. Lateral and dorsal views of adult males of Stenocercus for comparison: (A, C, E) S. dracopennatus (CORBIDI 18875) and (B, D, F) S. aculeatus (CORBIDI 1712). Photographs by Luis A. Garcia-Ayachi. Scale bars: 10 mm.

Figure 16. Dorsolateral and ventral views of Stenocercus aculeatus in life: (A, B, E) adult female (CORBIDI 21983) from San Ramon, Department of Junin, Central Peru; (C, D, F) adult female (CORBIDI 17739) from La Convencion, Department of Cusco, southern Peru; (G, H) adult male, (CORBIDI 17738) from La Convencion, Department of Cusco, southern Peru. Photographs by Juan C. Chavez-Arribasplata.