Stenocercus empetrus Fritts, 1972

Torres-Carvajal, Omar, 2007, A TAXONOMIC REVISION OF SOUTH AMERICAN STENOCERCUS (SQUAMATA: IGUANIA) LIZARDS, Herpetological Monographs 21 (1), pp. 76-178 : 106-107

Stenocercus empetrus Fritts

( Fig. 14 )

Stenocercus empetrus Fritts, 1972:7 . Holotype: KU 134394 , a male from ‘‘ Huamachuco , 3350 m, Departamento La Libertad, Perú ̕̕; Fritts, 1974:47.

Diagnosis.— Stenocercus empetrus differs from all other species of Stenocercus except S. bolivarensis , S. carrioni , S. chlorostictus , S. crassicaudatus , S. eunetopsis , S. simonsii , and S. torquatus in having granular scales on the posterior surface of thighs, two caudal whorls per autotomic segment, mucronate caudal scales, and a longitudinal row (continuous or discontinuous) of enlarged vertebral scales. In these species the dorsal scales on neck and body are granular in S. crassicaudatus , S. simonsii , and S. torquatus . S. empetrus can be distinguished from S. bolivarensis , S. carrioni , and S. eunetopsis by having more (85–111) scales around midbody (67–82, 66–96, and 60–80, respectively). It differs from S. chlorostictus by lacking caudal scales with strongly projected mucrons, and presumably by attaining a larger size ( Table 2 ). Furthermore, the dorsal background color in S. empetrus is not green as in some male specimens of S. chlorostictus .

Description.—(1) Maximum SVL in males 103 mm (n = 20); (2) maximum SVL in females 90 mm (n = 17); (3) vertebrals 68– 105; (4) paravertebrals 83–111; (5) scales around midbody 85–111; (6) supraoculars 5– 7; (7) internasals 3–4; (8) postrostrals 4–8; (9) loreals 2–5; (10) gulars 36–49; (11) subdigitals on Finger IV 17–24; (12) subdigitals on Toe IV 22–30; (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 juxtaposed; (20) preauricular fringe present; (21) antegular (continuous medially), antehumeral, gular, longitudinal, oblique, and postauricular neck folds present; (22) lateral nuchals less than half the size of dorsal nuchals; (23) posterior gulars cycloid, smooth, slightly 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 53– 61% of total length; (34) caudal whorls per autotomic segment two; (35) caudals 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 adult males absent; (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) postxiphisternal inscriptional ribs not in contact midventrally, Patterns 1A and 1B.

Color in life.—Dorsum black, brown, or gray, with yellow flecks and spots; interorbital and occipital regions with red spots; venter yellowish orange in males and yellow in females, with black reticulations in both sexes ( Fritts, 1972; Schlüter, 1999 c, d, 2005). Remarkably, juveniles of Stenocercus empetrus from nearby the type locality have partially red or orange tails ( Schlüter, 2005). Brightly colored tails in juveniles are not known in other species of Stenocercus ; moreover, this condition is uncommon among iguanian lizards.

Natural History.—A female laid six eggs in captivity in June 1998 ( Schlüter, 1999 d). Incubation time was 112 days at a temperature of 22–25 C; SVL of hatchlings was about 32 mm. Mostly found in mesic habitats, this species is active in large rock piles and rock exposures ( Fritts, 1972).

Distribution.— Stenocercus empetrus occurs between 8 ° S–6 ° S in the western Cordillera of Peru (central Andes). It is known from the upper valleys of Río Marañón (Atlantic drainage) at elevations of 2650–3200 m in Departamentos Cajamarca and La Libertad ( Fig. 15 ). This species is sympatric with S. melanopygus at several localities. Fritts (1974) reported S. empetrus from the upper valley of Río Moche (Pacific drainage) based on erroneous locality data ( Cadle, 1991).

Figures

FIG. 14.—Eight species of Stenocercus. (A) S. chota (LAC); (B) S. chrŋsopŋgus (MLU); (C) S. crassicaudatus (WED); (D) S. cupreus (MLU); (E) S. doellojuradoi (JAS); (F) S. dumerilii (TAP); (G) S. empetrus (RON); (H) S. festae (OTC).

FIG. 15.—Distribution of four species of Stenocercus in Peru.