Crocodilurus Spix

Harvey, Michael B., Ugueto, Gabriel N. & Gutberlet, Ronald L., 2012, 3459, Zootaxa 3459, pp. 1-156 : 133-136

Crocodilurus Spix

Figure 75

Crocodilurus Spix 1825: 19 . Type species Crocodilurus amazonicus Spix by subsequent designation ( Massary & Hoogmoed 2001).

Diagnosis.— Crocodilurus possesses several characters found in no other Teiidae . These include (1) an elongate fifth toe extending beyond the proximal free phalangeal articulation of Toe IV, (2) apical granules on the flanks that point upward and anteriorly from a fold of skin behind each dorsal so that each granule’s pointed apex contacts the apex of the preceding dorsal, and (3) long, styloid apical awns on the hemipenis, each separated from an exceptionally pronounced catchment fold by a deep groove.

Content.— Crocodilurus amazonicus Spix.

Definition.—Large lizards reaching 222 mm SVL; tail about twice as long as body ( Table 15); posterior maxillary and dentary teeth longitudinally compressed, tricuspid; pupil reniform.

Prefrontal separated from nasal, contacting first supraciliary; frontal entire, lacking longitudinal ridge; posterior suture of frontal contacting second or third supraocular; scales of frontoparietal region smooth; key-hole shaped depression well-developed; frontoparietals paired; parietals consisting of three regular scales; interparietal entire, variable in size; medial pair of enlarged occipitals present; occipitals 2–9, larger than scales in first row of dorsals; supratemporals forming distinctive row of large, angulate scales behind supraciliaries; supratemporals broadly contacting parietals.

Rostral groove absent; nostril subcircular to subtriangular, centered in nasal suture; loreal single; supraoculars eight; first supraocular entire, smaller than fourth supraocular, in contact with second supraocular; circumorbital semicircles absent; supraciliaries subequal, 14–18, in contact with supraoculars (i.e., lateral supraocular granules absent); subocular keel absent; suboculars 4–6; suboculars below eye contacting supralabials; first subocular contacting or separated from first supraciliary, contacting supralabials or separated from supralabials by anterior expansion of second subocular; scales in front of auditory meatus slightly enlarged; auricular flap and preauricular fold absent.

Supralabials 12–13; first supralabial subequal to or longer than second, its ventral margin straight; infralabials 10–13; first pair of chinshields in contact with infralabials or partially separated from them by granular scales; first pair of chinshields in medial contact; interangular sulcus absent; anterior gulars 21–22; gular patch absent; posterior gulars 8; intertympanic sulcus filled with small granular scales, complete medially; larger anterior gulars not undergoing transition to smaller posterior gulars at intertympanic sulcus; mesoptychials moderately enlarged, not forming differentiated transverse row or serrated edge of gular fold.

Dorsals convex to keeled; scales on flank subequal to middorsals; apical granule pointed, curving upward and anterior from fold of skin posterior to each dorsal, its pointed apex touching apex of preceding dorsal; scales on rump slightly smaller than proximal subcaudals; scales of chest large and flat; pectoral sulcus absent; ventrals smooth, in 35–38 transverse and 20–21 longitudinal rows; subrectangular scales lateral to ventrals gradually decreasing in size on flanks, bordering transverse folds of skin; preanals 4–5; preanal plate present; preanal spurs and postanal plates absent; postcloacal buttons present in males; tail flattened; dorsolateral crests on tail consisting of enlarged heavily keeled scales projecting at about 45° to tail; accessory crests at base of tail consisting of four rows of enlarged heavily keeled scales between dorsolateral crests and second pair positioned laterally; medial rows of accessory crests separated by 9–10 rows of flat, elongate, and keeled scales, others by 1–2 rows of scales; complete caudal annuli alternating with annuli complete ventrally but divided on sides and dorsum of tail; proximal subcaudals smooth.

Preaxial brachials 1–2 X as wide as long, differentiated from large flat scales covering rest of brachium (scales largest on preaxial and dorsal brachium and antebrachium, grading to granular scales postaxially); antebrachium covered in scales longer than wide; scales on proximal, ventral surface of antebrachium slightly enlarged; subdigital lamellae of hand homogeneous in size, mostly divided, 20–21 under fourth finger.

Prefemorals 15–19; femoral and abdominal pores 21–28; each compound pore-bearing scale consisting of partially fused prefemoral or abdominal scale and 2 or more granular scales; 4–6 scales separating abdominal pore series medially; distal-most femoral pores not separated from others; gap of about 4 granular scales separating femoral from abdominal pores; scales at heel relatively small and numerous; tibiotarsal spurs and shields absent; lamellae under fourth toe 28–30; distal lamellae of fourth toe smooth; scales between subdigital and supradigital lamellae along postaxial side of toes serrate; noticeably enlarged postaxial scales between fourth and fifth toe absent; fifth toe well-developed, base of its claw surpassing proximal free phalangeal articulation of fourth toe.

β- keratin containing layers of dorsal trunk scales lacking macrohoneycomb, instead uniformly covered in simple lamellae; long aligned macroridges covering supracaudal scales; single subterminal lenticular scale organ positioned atop keel on dorsals and proximal supracaudals; ventrals lacking scale organs; generation glands absent. Snout same color as dorsal head scales. In juveniles, light vertebral, paravertebral, dorsolateral, upper and lower lateral stripes absent; dark dorsolateral and lateral fields absent; thigh lacking light spots. Adult males lacking flank spots but with conspicuous light ocelli; turquoise ventrolateral spots absent; venter with large melanic; juvenile dorsal color pattern present in adult males with only slight modification.

Hemipenis with pair of long, styloid apical awns, each separated by deep groove from exceptionally pronounced sulcate catchment fold extending distally from organ as triangular flap; apical papillae and apical basin absent; asulcate expansion pleat well-developed, interrupting about 44 distal laminae; discontinuous distal laminae absent; about 29 laminae proximal to expansion pleat; basal papillae absent.

Etymology.— Spix (1825) did not discuss the etymology of Crocodilurus . The name is likely derived from the Greek nouns krokodeilos originally meaning lizard and oura meaning tail. In his generic description, Spix (1825) emphasized characteristics of the tail, which resembles that of crocodilians.

Distribution.— Crocodilurus occurs along the Amazon and Orinoco Rivers and their tributaries in Brazil, Colombia, Peru, and Venezuela. This species is known from a few localities in coastal French Guiana and Pará, Brazil. Bertoni (1926) reported a specimen from Paraguay where locals apparently refer to this species as “yakarerâ.” Since all other known localities are above about 5°S latitude, Bertoni’s report is surprising and should be confirmed.