Stenocercus sinesaccus Torres-Carvajal, 2005

Torres-Carvajal, Omar, 2007, A TAXONOMIC REVISION OF SOUTH AMERICAN STENOCERCUS (SQUAMATA: IGUANIA) LIZARDS, Herpetological Monographs 21 (1), pp. 76-178 : 155-156

Stenocercus sinesaccus Torres-Carvajal

Stenocercus sinesaccus Torres-Carvajal, 2005 c: 124 . Holotype: BMNH 1903.3.26.7 , a male from ‘‘Chapada [ Chapada dos Guimarães , 15 ° 26'S, 55 ° 45'W, 690 m], Mato Grosso, Brazil.̕̕

Stenocercus caducus (part) Cope, 1887:55; Etheridge, in Peters and Donoso-Barros, 1970:213; Cei, 1993:302. Synonymy fide Torres-Carvajal, 2005 c:124.

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. S. sinesaccus differs from S. dumerilii , S. quinarius , S. squarrosus and S. tricristatus in lacking enlarged post-supraciliaries and a pyramidal head; S. scapularis differs from S. sinesaccus in having a distinct postfemoral mite pocket and projected supraciliaries. S. sinesaccus also resembles S. caducus and S. prionotus , from which it differs in lacking a posthumeral mite pocket; the latter two species have a deep posthumeral mite pocket covered by an axillary flap ( Cadle, 2001; Torres-Carvajal, 2005 c).

Description.—(1) Maximum SVL in males 73 mm (n = 3); (2) maximum SVL in females 81 mm (n = 1); (3) vertebrals 28–30; (4) paravertebrals 32–34; (5) scales around midbody 31–34; (6) supraoculars four; (7) internasals six; (8) postrostrals 4–5; (9) loreals three; (10) gulars 12–14; (11) subdigitals on Finger IV 13–16; (12) subdigitals on Toe IV 23–25; (13) posthumeral mite pocket absent; (14) postfemoral mite pocket absent; (15) parietal eye always visible through interparietal cornea; (16) scales on occipitoparietal region large, imbricate, strongly keeled; (17) projecting angulate temporals absent; (18) one row of enlarged supraoculars occupying most of supraocular region absent; (19) scales on frontonasal region imbricate anteriorly; (20) preauricular fringe inconspicuous or absent; (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, mucronate; (28) scales on posterior surfaces of thighs keeled, imbricate; (29) inguinal granular pocket absent; (30) inguinal groove absent; (31) preanals projected; (32) tail not compressed laterally in adult males; (33) tail length 70–73% of total length; (34) caudal fracture planes absent; (35) caudals not spinose; (36) dark brown stripe extending anterodorsally from subocular region to supraciliaries present; (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 continuous midventrally, Pattern 6A.

Color in life.—Although data on color in life of S. sinesaccus are not available, preserved male specimens still retain an iridescent pink tint on the ventrolateral edges of the body between fore and hind limbs ( Torres-Carvajal, 2005 c).

Natural History.—Based on similarity in color patterns and morphology, Torres-Carvajal (2005 c) suggested that S. sinesaccus might adopt the same defense behavior as S. caducus , which remains immobile while displaying its colorful (pink or purple) ventrolateral body edges and moving the snout downwards ( Scrocchi et al., 1985).

Distribution.— Stenocercus sinesaccus is known from Estados Goiás, Mato Grosso, and Rondônia in western Brazil ( Fig. 11 ). These localities lie mostly within the Cerrado Biome (savanna) east of the central Andes in Bolivia and west of the Araguaia basin.

Figures

FIG. 11.—Distribution of six species of Stenocercus in South America.