Stenocercus squarrosus Nogueira and Rodrigues

Torres-Carvajal, Omar, 2007, A TAXONOMIC REVISION OF SOUTH AMERICAN STENOCERCUS (SQUAMATA: IGUANIA) LIZARDS, Herpetological Monographs 21 (1), pp. 76-178 : 156-157

Stenocercus squarrosus Nogueira and Rodrigues

Stenocercus squarrosus Nogueira and Rodrigues, 2006:158 . Holotype: MZUSP 94056 , a male from ‘‘ Chapada dos Gerais , Parque Nacional Serra das Confusões , 9 ° 13'S, 43 ° 29'W, Estado Piauí, Brazil.̕̕

Diagnosis.—Among species of Stenocercus , S. dumerilii , S. quinarius , S. scapularis , S. sinesaccus , S. squarrosus , and S. tricristatus are unique in lacking caudal fracture planes. Of these species, only S. dumerilii , S. quinarius , S. squarrosus and S. tricristatus have a pyramidal head, as well as enlarged, dorsally-projected posterior supraciliaries. Among other differences, S. squarrosus can be distinguished from S. dumerilii and S. tricristatus (character states in parentheses) by having a shorter—44–47% of total length— tail (53–58% and 68%, respectively) and more scales—46–53, X = 49.50—around midbody (41–50, X = 45.30 and 33, respectively; Nogueira and Rodrigues, 2006). It differs from S. quinarius mainly in having a shorter tail (44–47% and 50–52% of total length, respectively) and prominent dorsal, dorsolateral, and lateral crests (corresponding crests inconspicuous in S. quinarius ; Nogueira and Rodrigues, 2006).

Description.—(1) Maximum SVL in males 88 mm (n = 6); (2) maximum SVL in females 88 mm (n = 6); (3) vertebrals 22–27; (4) paravertebrals 35–45; (5) scales around midbody 46–53; (6) supraoculars in holotype 4–5 ( Fig. 6 in Nogueira and Rodrigues, 2006); (7) internasals 3–5; (11) subdigitals on Finger IV 13–15; (12) subdigitals on Toe IV 16–20; (13) posthumeral mite pocket absent; (14) postfemoral mite pocket absent; (15) parietal eye visible through interparietal cornea; (16) scales on occipitoparietal region large, keeled, juxtaposed; (18) row of enlarged supraoculars occupying most of supraocular region absent; (20) preauricular fringe present; (21) neck folds absent; (22) lateral and dorsal nuchals similar in size; (23) posterior gulars rhomboidal, projected posteriorly, strongly keeled and imbricate, not notched; (24) lateral and dorsal body scales similar in size; (25) vertebrals larger than adjacent paravertebrals; (26) dorsolateral crest present; (27) ventrals keeled, imbricate; (28) scales on posterior surfaces of thighs keeled, imbricate; (29) inguinal granular pocket absent; (30) inguinal groove absent; (32) tail not compressed laterally in adult males; (33) tail length 44– 47% of total length; (34) caudal autotomic segments absent; (35) caudals not spinose; (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.

Color in life.—Dorsum tan; dark brown stripe extending anterodorsally from subocular region to supraciliaries; gular and ventral areas light brown; tail with dark flecks; black spot on shoulder ( Nogueira and Rodrigues, 2006).

Distribution.— Stenocercus squarrosus is only known from its type locality (9 ° 13'S, 43 ° 29'W) in Estado Piauí, Brazil ( Fig. 13 ). This locality lies in a contact area between the Caatinga and Cerrado biomes ( Nogueira and Rodrigues, 2006). This species is not known to occur in sympatry with other species of Stenocercus .

Figures

FIG. 6.—Distribution of five species of Stenocercus in Peru.

FIG. 13.—Distribution of seven species of Stenocercus in South America. Question mark indicates possible distribution of S. tricristatus.