Stenocercus tricristatus (DUMÉRIL, 1851)
Can you confirm these amateur observations of Stenocercus tricristatus?
|Higher Taxa||Tropiduridae, Iguania, Sauria, Squamata (lizards)|
|Synonym||Ophryoessoides tricristatus DUMÉRIL in DUMÉRIL & DUMÉRIL 1851: 66|
Liocephalus tricristatus — BOULENGER 1885: 170
Ophryoessoides tricristatus — ETHERIDGE 1966: 88
Ophryoessoides tricristatus — PETERS et al. 1970: 215
Stenocercus tricristatus — AVILA-PIRES 1995
Stenocercus tricristatus— TORRES-CARVAJAL et al. 2006
Stenocercus cf. tricristatus —TEXEIRA et al. 2015
Stenocercus tricristatus — AVILA-PIRES et al. 2019
|Distribution||SE Brazil (Minas Gerais)|
Type locality: Minas Gerais, Brazil (unknown locality).
|Types||Holotype: MNHN-RA 6825, collected by Peter Claussen, a Danish who lived in Brazil for about 20 years.|
|Diagnosis||Diagnosis: TORRES-CARVAJAL 2007.|
Diagnosis: Stenocercus tricristatus is characterized by the following combination of features: (1) Dorsal head scales keeled. (2) Interparietal distinct, moderately enlarged; posterior head scales variable in size. (3) Internasals six. (4) No distinctly enlarged supraoculars. (5) An enlarged canthal at each side, in contact anteriorly with two elongate scales that form a double canthal ridge. (6) An enlarged, prominent, obtusely pointed scale immediately posterior to supraciliaries; no projecting, blade-like, angulate temporal scales. (7) Gulars and ventrals distinctly keeled. (8) Parietal eye distinct. (9) Neck folds absent. (10) Dorsals phylloid, keeled, mucronate and imbricate; scales on flanks similar to dorsals. (11) A moderately prominent, serrate vertebral crest, and a slightly less prominent dorsolateral crest (a less conspicuous lateral crest may be present, but it is not very clear from the present condition of the specimen). (12) Mite pockets absent. (13) Scales on posterior surface of thighs imbri- cate, keeled. (14) Tail moderately compressed, verticils absent. (15) Dorsal coloration probably with numerous dark brown spots on back and flanks; head with at least a large, triangular spot on posterior part of snout. (16) Scales around midbody 33, ventrals between anterior margin of forelimbs and anterior margin of hind limbs 23. (17) No distinctly enlarged scale on anterior margin of ear-opening.
Stenocercus tricristatus is distinguished from all other Stenoc ercus except S. canastra sp. nov., S. quinarius, S. squarrosus and S. dumerilii by the presence of an enlarged, prominent post-supraciliary scale; from all others except S. canastra sp. nov., S. quinarius and S. squarrosus by a moderately enlarged interparietal (although not as large as in the Tropidurini). It is distinguished from S. dumerilii, S. quinarius and S. squarrosus (character states in parentheses) by the presence of a prominent, serrate vertebral crest (in contrast to a low vertebral crest); two supraciliaries (4, rarely 3); absence of two distinctly enlarged upper temporals (two distinctly enlarged upper temporals); preauricular scale projecting over the tympanum, keeled (preauricular scale not or only slightly projecting over the tympanum, smooth); dor- sals distinctly keeled and mucronate (dorsals with a low keel, not or hardly mucronate); 7–8 scales across midbody from one dorsolateral row to the other (11–13 in S. dumerilii, 13–15 in S. quinarius and S. squarrosus); ventrals between anterior level of fore- and hind limbs 22 (28–32 in S. dumerilii, 30–34 in S. quinarius, 28–34 in S. squarrosus); scales on chin subequal and imbricate (scales on chin smaller, poligonal and subimbricate anteriorly, grading into larger, pointed, and imbricate posteri- orly); tail 1.7 times SVL, slightly depressed near base (at most 1.4 times, compressed near base); and color pattern (Table 1). From S. canastra sp. nov. it differs by its wider head when seen from the ventral side (0.96 times as wide as long versus 0.78–0.89 times); 33 scales around midbody (39–41); preauricular scale about as large as adjacent temporals, keeled (distinctly larger, smooth); and no pre-subocular larger than adjacent scales (a larger pre-subocular in S. canastra sp. nov.). Besides, it reaches probably a smaller adult size (57 mm versus ≥ 70 mm in adult males of S. canastra sp. nov.).
|Comment||Stenocercus dumerilii, S. tricristatus, S.quinarius, and S. squarrosus share combined morphological features (three or five dorsal crests, enlarged post-supraciliary scale, head blunt, pyramidal, bordered by supraciliary crests) unseen in the remainder of the genus (see Avila-Pires 1995, Nogueira & Rodrigues 2006).|
Type Species: Ophryoessoides tricristatus is the type species of the genus Ophryoessoides DUMÉRIL 1851.
Distribution: see map in TEIXEIRA et al. 2015: 417. The type locality of S. tricristatus comes from the State of Minas Gerais, most likely from its central, upland areas in or near the Espinhaço range, where most localities cited by Claussen are located, including the two farms where he lived while collecting in Brazil (Luna Filho 2007).
Abundance: only known from the type specimen (Meiri et al. 2017, Avila-Pires et al. 2019).
Habitat. Unknown fide Avila-Pires et al. 2019, but expected to occur either in cerrado veg- etation or in shrublands on rock outcrops, both of which are widespread in these areas.