Stenocercus iridescens (Günther)

Torres-Carvajal, Omar, 2007, A TAXONOMIC REVISION OF SOUTH AMERICAN STENOCERCUS (SQUAMATA: IGUANIA) LIZARDS, Herpetological Monographs 21 (1), pp. 76-178 : 128-129

Stenocercus iridescens (Günther) ( Fig. 18 )

Liocephalus iridescens Günther, 1859 b:409 . Syntypes: BM 60.6.16.2–7 , from ‘‘ Andes of western Ecuador ̕̕; Boulenger, 1885 a:167.

Leiocephalus iridescens iridescens Burt and Burt, 1930:12 ; Burt and Burt (part), 1931:269; Burt and Burt, 1933:28; Burt and Myers, 1942:302.

Ophryoessoides iridescens Etheridge, 1966:88 ; Peters, 1967:28; Etheridge, in Peters and Donoso-Barros, 1970:214; Ayala, 1986:563.

Stenocercus iridescens Frost, 1992:43 ; Torres-Carvajal, 2000:24; Cadle, 2001:184.

Diagnosis.— Stenocercus iridescens can be distinguished from other species of Stenocercus except S. erythrogaster , S. huancabambae , S. limitaris , S. puyango and S. santander by having imbricate scales on posterior aspect of thighs, nostrils medial to canthal ridge, and a longitudinal row of enlarged supraoculars occupying most of the supraocular region. Of these species, only S. erythrogaster and S. iridescens lack a postfemoral mite pocket. S. iridescens differs from S. erythrogaster (character states in parentheses) by having smooth dorsal head scales (keeled or wrinkled) and smooth ventrals in adults (distinctly keeled).

Description.—(1) Maximum SVL in males 99 mm (n = 28); (2) maximum SVL in females 81 mm (n = 37); (3) vertebrals 40–52; (4) paravertebrals 43–58; (5) scales around midbody 35–52; (6) supraoculars 2–5; (7) internasals 2–4; (8) postrostrals 4–5; (9) loreals 2–5; (10) gulars 16–20; (11) subdigitals on Finger IV 15–18; (12) subdigitals on Toe IV 22–28; (13) posthumeral mite pocket present as a shallow depression with a wide opening; (14) postfemoral mite pocket absent; (15) parietal eye visible through interparietal cornea in 88% of specimens; (16) scales on occipitoparietal region large, smooth, imbricate; (17) projecting angulate temporals absent; (18) one row of enlarged supraoculars occupying most of supraocular region; (19) scales on frontonasal region weakly imbricate anteriorly; (20) preauricular fringe present; (21) neck folds absent; (22) lateral and dorsal nuchals similar in size; (23) posterior gulars rhomboidal, smooth or slightly keeled, imbricate, not notched; (24) lateral and dorsal body scales similar in size; (25) vertebrals larger than adjacent paravertebrals; (26) dorsolateral crest absent; (27) ventrals smooth or indistinctly keeled, imbricate; (28) scales on posterior surfaces of thighs keeled, imbricate; (29) inguinal granular pocket absent; (30) inguinal groove absent; (31) preanals projected; (32) tail strongly compressed laterally in adult males; (33) tail length 65–70% 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; (37) dark patch extensively covering gular region in 14% of females; (38) dark patch extensively covering gular region of adult males absent; (39) black patch on ventral surface of neck in adult males always present; (40) dark midventral longitudinal mark such as faint line, conspicuous stripe, or extensive patch in adult males always present; (41) dark patches on ventral surface of thighs in adult males absent; (42) postxiphisternal inscriptional ribs continuous midventrally, Patterns 5, 6A.

Color in life.—Dorsum brown with dark chevrons, more distinct on neck; vertebrals light blue in some male specimens; vertical white line on shoulder; white longitudinal line extending from tympanum to midbody in some females; sides of head white or cream in females; dark brown stripe extending anterodorsally from subocular region to supraciliaries; dark brown interorbital bar in some specimens; gular region mostly red with scattered black dots (also present around tympanum) in males; black patch on ventral surface of neck in males; throat bright yellow in males; venter lavender pink; iris copper ( Schlüter, 2001 b; Torres-Carvajal, 2000, 2005 a).

Distribution.— Stenocercus iridescens is known from the western slopes of the northern Andes and adjacent Pacific lowlands of Ecuador and southern Colombia between 3 ° 30'S–2 ° N ( Fig. 8 ). This species occurs at elevations of 0–2000 m in Provincias Azuay, Chimborazo, Cotopaxi, El Oro, Esmeraldas, Guayas, Imbabura, Los Ríos, and Manabí in Ecuador, as well as Departamento Nariño in Colombia.

Figures

FIG. 18.—Eight species of Stenocercus. (A) S. fimbriatus (JCA); (B) S. formosus (MLU); (C) S. guentheri (LAC); (D) S. humeralis (OTC); (E) S. imitator (PVE); (F) S. iridescens (RWM); (G) S. lache (JMR); (H) S. limitaris (PVE).

FIG. 8.—Distribution of six species of Stenocercus in Colombia and Ecuador.