Stenocercus caducus (Cope)

Torres-Carvajal, Omar, 2007, A TAXONOMIC REVISION OF SOUTH AMERICAN STENOCERCUS (SQUAMATA: IGUANIA) LIZARDS, Herpetological Monographs 21 (1), pp. 76-178 : 94-95

Stenocercus caducus (Cope)

( Fig. 7 )

Scartiscus caducus Cope, 1862:182 . Holotype: USNM 5852 , a female from ‘‘ Paraguay ̕̕; Boulenger, 1885 a:127.

Liocephalus bolivianus Boulenger, 1890:82 . Holotype: BMNH 89.12.16.25 (RR 1946. 8.29.76), a female from ‘‘ Bolivia.̕̕ Synonymy fide Boulenger, 1894:342.

Liocephalus caducus Boulenger, 1894:342 .

Scartiscus liocephaloides Werner, 1910:23 . Synonymy fide Etheridge in Peters and Donoso-Barros, 1970:213.

Leiocephalus liocephaloides Burt and Burt, 1933:28 .

Leiocephalus caducus Burt and Burt, 1930:12 ; Burt and Burt, 1931:269; Burt and Burt, 1933:26.

Ophryoessoides liocephaloides Etheridge, 1966:88 .

Ophryoessoides caducus Etheridge, 1966:88 ; Etheridge, in Peters and Donoso-Barros, 1970:213.

Stenocercus caducus Frost, 1992:43 ; Cei, 1993:302; Cadle, 2001:184.

Diagnosis.—Among species of Stenocercus with strongly keeled ventrals and laterally oriented nostrils, S. caducus is similar to S. aculeatus , S. angulifer , S. fimbriatus , S. prionotus , and S. scapularis in having a distinct posthumeral mite pocket. Of these species, only S. caducus , S. fimbriatus , and S. prionotus lack a postfemoral mite pocket. Furthermore, S. caducus and S. prionotus are unique in having an axillary flap covering the antehumeral mite pocket ( Cadle, 2001). S. caducus can be distinguished from S. prionotus by lacking projecting angulate temporals (two projecting angulate temporals in S. prionotus ), and by having a less prominent vertebral crest.

Description.—(1) Maximum SVL in males 72 mm ( Cadle, 2001); (2) maximum SVL in females 93 mm ( Cadle, 2001); (3) vertebrals 30–43; (4) paravertebrals 42–50; (5) scales around midbody 34–44; (6) supraoculars 4–6; (7) internasals 6–8; (8) postrostrals 4–7; (9) loreals 3–5; (10) gulars 16–23; (11) subdigitals on Finger IV 15–21; (12) subdigitals on Toe IV 23–30; (13) posthumeral mite pocket present as a deep depression covered by an axillary flap; (14) postfemoral mite pocket absent; (15) parietal eye visible through interparietal cornea in 97% of specimens; (16) scales on occipitoparietal region large, keeled, 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 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, mucronate; (29) inguinal granular pocket absent; (30) inguinal groove absent; (31) preanals projected; (32) tail not compressed laterally in adult males; (33) tail length 67– 74% 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 always present; (37) dark patch extensively covering gular region of females absent; (38) dark patch extensively covering gular region in 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.—Dorsum tan or dark brown with darker chevrons arranged longitudinally on vertebral line; head with dark brown interorbital bar and oblique stripe extending anterodorsally from subocular region to supraciliaries; white or yellowish-cream vertical line extending from insertion of fore limb to dorsolateral crest; venter gray or brown with scattered light blotches; ventrolateral aspect of body light pink or purple ( Cei, 1993; Marcus, 1986; Scrocchi et al., 1985).

Natural History.—Based on the stomach contents of 10 adult specimens, Marcus (1986) reported the following food items for S. caducus : Arachnida (scorpions), Lepidoptera ( Sphingidae adults and other unidentified families), Diptera (unidentified larvae), Hymenoptera ( Formicidae , including Solenopsis ; larvae of Vespidae ), Coleoptera (larvae of Tenebrionidae and Scarabeidae ), Orthoptera, and Oligochaeta. Scrocchi et al. (1985) observed individuals of S. caducus that remained immobile after adopting a position in which the pink ventrolateral edges of the body between fore and hind limbs were displayed; moreover, as part of this behavior, the snout was moved downwards giving the lizard the appearance of being dead.

Distribution.— Stenocercus caducus occurs in the eastern Cordillera of the central and southern Andes and adjacent lowlands (26 ° S– 14 ° S) at elevations between 50–2000 m ( Fig. 13 ). It is known from Argentina (Provincias Jujuy, Salta; Marcus, 1986), Bolivia (Departamentos Beni, Chuquisaca, Cochabamba, Santa Cruz, Tarija), Brazil (Estados Mato Grosso, Mato Grosso do Sul; Nogueira and Rodrigues, 2006), and Paraguay (Departamentos Alto Paraguay, Amambay, Caaguazu, Canindeyu, Central, Itapua, and Paraguari). This species is known to occur in sympatry with S. roseiventris (Bolivia: Santa Cruz).

Figures

FIG. 7.—Eight species of Stenocercus. (A) S. angel (LAC); (B) S. angulifer (FAY); (C) S. apurimacus (WED); (D) S. azureus (SCA); (E) S. boettgeri (MLU); (F) S. boliƲarensis (FCA); (G) S. caducus (LSI); (H) S. chlorostictus (MLU).

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