Stenocercus variabilis Boulenger, 1901

Torres-Carvajal, Omar, 2007, A TAXONOMIC REVISION OF SOUTH AMERICAN STENOCERCUS (SQUAMATA: IGUANIA) LIZARDS, Herpetological Monographs 21 (1), pp. 76-178 : 162-163

Stenocercus variabilis Boulenger ( Fig. 22 )

Stenocercus variabilis Boulenger, 1901:546 . Syntypes: BMNH 1946.8.11.89–91 , from ‘‘Palca, 1000 ft., Bolivia̕̕ (restricted to Palca [2875 m], Departamento Junín, Peru by Fritts [1974:65]); Fritts (part), 1974:65; Etheridge, in Peters and Donoso-Barros, 1970:257.

Stenocercus juninensis Shreve, 1941:75 . Holotype: MCZ 45820, from ‘‘Huasqui [3822 m], near Tarma, Departamento Junín, Peru.̕̕ Synonymy fide Fritts, 1974:65.

Diagnosis.— Stenocercus variabilis is distinguished from all species of Stenocercus except S. frittsi in having granular scales on the posterior surface of thighs, imbricate and keeled lateral body scales, a distinct row of enlarged vertebral scales, unnotched gular scales, three caudal whorls per autotomic segment, gray or brown dorsal ground color, and distinct neck folds, of which the antegular fold is not continuous medially. The main difference between S. variabilis and S. frittsi is that the former species has a deep postfemoral mite pocket (absent in S. frittsi ). In addition, S. variabilis is larger than S. frittsi (maximum SVL = 94 mm and 79 mm in males, 76 mm and 66 mm in females, respectively), and it has on average more scales around the midbody (61–86, X = 71.29 and 60–76, X = 65.14), as well as more gulars (26– 33, X = 28.29 and 20–28, X = 22.63), paravertebrals (70–81, X = 75.71 and 59–90, X = 70.16), and subdigitals on Toe IV (26–35, X = 30.00 and 24–29, X = 26.98).

Description.—(1) Maximum SVL in males 94 mm (n = 15); (2) maximum SVL in females 76 mm (n = 4); (3) vertebrals 50–60; (4) paravertebrals 70–81; (5) scales around midbody 61–86; (6) supraoculars 5–7; (7) internasals 3–4; (8) postrostrals six; (9) loreals 2–4; (10) gulars 26–33; (11) subdigitals on Finger IV 19–24; (12) subdigitals on Toe IV 26–35; (13) posthumeral mite pocket present as one or more vertical folds or ridges; (14) postfemoral mite pocket distinct with slit-like opening; (15) parietal eye not visible through interparietal cornea; (16) scales on occipitoparietal region small, smooth, juxtaposed; (17) projecting angulate temporals absent; (18) row of enlarged supraoculars occupying most of supraocular region absent; (19) scales on frontonasal region weakly imbricate anteriorly; (20) preauricular fringe present; (21) antegular (continuous medially), antehumeral, gular, longitudinal, oblique, postauricular, and supra-auricular neck folds present; (22) lateral nuchals less than half the size of dorsal nuchals; (23) posterior gulars rhomboidal, smooth or slightly keeled, imbricate, not notched; (24) lateral scales reduced in size, approximately half the size of dorsal body scales; (25) vertebrals larger than adjacent paravertebrals; (26) dorsolateral crest absent; (27) ventrals smooth, imbricate; (28) scales on posterior surfaces of thighs granular; (29) inguinal granular pocket present; (30) inguinal groove present; (31) preanals not projected; (32) tail not compressed laterally in adult males; (33) tail length 60–67% 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 absent; (37) dark patch extensively covering gular region of females absent; (38) dark patch extensively covering gular region of adult males absent; (39) black patch on ventral surface of neck in 9% of adult males; (40) dark midventral longitudinal mark such as faint line, conspicuous stripe, or extensive patch in 9% of adult males; (41) dark patches on ventral surface of thighs in adult males absent; (42) pattern of postxiphisternal inscriptional rib attachment unknown (specimens identified as S. variabilis in Torres-Carvajal [2004 a] correspond to S. frittsi .).

Color in preservative of syntypes.—Dorsal ground color green with white spots laterally, or gray with black spots dorsally or laterally; venter whitish; throat marbled with olive; one specimen [BMNH 1946.8.11.89] with a black bar across scapular region and black throat and belly ( Boulenger, 1901).

Color in life.—Dorsum brown with light tan dorsolateral area in some females; middorsal irregular dark brown transverse bands extending onto base of tail in females; flanks variegated pale blue and pale medium brown with small clusters of black scales in some males; head medium brown with whitish spots in males; chin grayish white with pale blue reticulations in males; ventral surface of body light gray anteriorly and yellow posteriorly in females, and whitish beige with a pale yellow midventral stripe in males; iris bronze ( Torres-Carvajal, 2005 b).

Distribution.— Stenocercus variablis occurs in the central Andes (12 ° S–11 ° S) on the eastern Cordillera of Peru ( Fig. 12 ). This species is known from the upper valley of Río Perene (Atlantic drainage) in Departamento Junín at elevations between 1557– 3822 m. Although no other species of Stenocercus is known to occur in sympatry with S. variabilis , there are other species— S. boettgeri , S. formosus , S. praeornatus , S. scapularis , and S. torquatus —inhabiting adjacent areas in the upper valleys of Río Perene ( Torres-Carvajal, 2005 b).

Figures

FIG. 22.—Six species of Stenocercus. (A) S. stigmosus (PVE); (B) S. torquatus (MLU); (C) S. trachŋcephalus (JMR); (D) S. tricristatus (illustration from plate XXII in Duméril, 1856); (E) S. Ʋariabilis (MLU); (F) S. Ʋarius (LAC).

FIG. 12.—Distribution of six species of Stenocercus in Peru. Black triangle pointed by arrow corresponds to María Teresa (10°42'05"S, 75°27'22"W, 1470 m, Departamento Pasco), where Stenocercus boettgeri, S. formosus, S. scapularis, and S. torquatus occur in sympatry.