Stenocercus ornatus (Gray)

Torres-Carvajal, Omar, 2007, A TAXONOMIC REVISION OF SOUTH AMERICAN STENOCERCUS (SQUAMATA: IGUANIA) LIZARDS, Herpetological Monographs 21 (1), pp. 76-178 : 141-142

Stenocercus ornatus (Gray)

( Fig. 21 )

Leiocephalus ornatus Gray, 1845:219 . Holotype: BM 1946.8.29.72 from ‘‘ Guayaquil [ Provincia Guayas , Ecuador]̕̕ (restricted to Loja, 2150 m, Provincia Loja, Ecuador, by Fritts [1974]).

Liocephalus ornatus Boulenger, 1885 a:168 .

Leiocephalus ornatus ornatus Burt and Burt, 1930:12 ; Burt and Burt (part), 1931:271; Burt and Burt (part), 1933:28; Burt and Myers, 1942:303.

Ophryoessoides ornatus Etheridge, 1966:88 ; Peters, 1967:28; Etheridge, in Peters and Donoso-Barros, 1970:214.

Stenocercus ornatus Fritts, 1974:62 ; Torres-Carvajal, 2000:27.

Diagnosis.— Stenocercus ornatus is distinguished from other species of Stenocercus except S. percultus and S. rhodomelas by having imbricate scales on the posterior surface of thighs, smooth ventrals, deep posthumeral and postfemoral mite pockets, and keeled dorsal head scales. S. ornatus differs from S. percultus and S. rhodomelas in lacking an extensive black patch on the gular region in adult males. In addition, the scales on the occipitoparietal region in S. ornatus have a central keel and are slightly imbricate, whereas these scales in S. percultus are multicarinate and juxtaposed. S. ornatus is further distinguished from S. rhodomelas by having an inconspicuous antehumeral fold (absent in S. rhodomelas ).

Description.—(1) Maximum SVL in males 85 mm (n = 23); (2) maximum SVL in females 71 mm (n = 9); (3) vertebrals 36–50; (4) paravertebrals 53–66; (5) scales around midbody 46–58; (6) supraoculars 4–7; (7) internasals 2–4; (8) postrostrals 4–6; (9) loreals 2–3; (10) gulars 15–23; (11) subdigitals on Finger IV 17–25; (12) subdigitals on Toe IV 27–37; (13) posthumeral mite pocket present as a deep depression; (14) postfemoral mite pocket distinct with slit-like opening; (15) parietal eye visible through interparietal cornea in 98% of specimens; (16) scales on occipitoparietal region small, keeled, slightly imbricate; (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) inconspicuous antehumeral fold present (supra-auricular and dorsolateral folds recorded by Torres-Carvajal [2000] in error); (22) lateral and dorsal nuchals similar in size; (23) posterior gulars rhomboidal, smooth, 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, imbricate; (28) scales on posterior surfaces of thighs keeled, imbricate; (29) inguinal granular pocket absent; (30) inguinal groove absent; (31) preanals not projected; (32) tail strongly compressed laterally in adult males; (33) tail length 66–72% 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 adult males absent; (40) dark midventral longitudinal mark such as faint line, conspicuous stripe, or extensive patch in 92% of adult males; (41) dark patches on ventral surface of thighs in 83% of adult males; (42) postxiphisternal inscriptional ribs not in contact midventrally, Patterns 2A and 2B.

Color in life.—Dorsum brown with dark transverse marks longitudinally arranged over vertebral line, and cream or beige dorsolateral stripes in some specimens; shoulder with large black blotch in males; chin black, light red, pink or yellow; gular region pale red or pinkish red in males; pectoral region with yellow patch in males; broad, black midventral stripe (medially separated by a yellow longitudinal line in some specimens) in males; ventral background pink or reddish cream, with gray dotted pattern in females; ventral surfaces of pelvic region, base of tail, and thighs yellow (heavily suffused with black in some specimens) in males ( Fritts, 1974; Torres-Carvajal, 2000).

Natural History.—Clutch size in S. ornatus is two eggs ( Torres-Carvajal, 2000). Fritts (1974) observed this species in open areas on the ground and in rows of Agave .

Distribution.— Stenocercus ornatus occurs between 4 ° 30'S–4 ° S in the western Cordillera and inter-Andean basins of the northern Andes in southern Ecuador ( Fig. 17 ). This species is known from Provincia Loja at elevations of 1500–3000 m in the upper valleys of Río Catamayo (Pacific drainage) and Río Zamora (Atlantic drainage), where it occurs in sympatry with S. humeralis .

Figures

FIG. 21.—Eight species of Stenocercus. (A) S. ornatus (OTC); (B) S. percultus (MLU); (C) S. praeornatus (WED); (D) S. puŋango (LAC); (E) S. quinarius (CNO); (F) S. roseiƲentris (WED); (G) S. santander (MPR); (H) S. simonsii (WED).

FIG. 17.—Distribution of four species of Stenocercus in Ecuador and Peru.