Neusticurus DUMERIL & BIBRON

NEUSTICURUS DUMÉRIL & BIBRON

Type species: Lacerta bicarinata Linnaeus, 1758: 201.

Neusticurus bicarinatus group: Uzzell, 1966: 311.

Definition: Tongue with imbricate, scale-like papillae. Nostril pierced in a single nasal; nasals separated usually by paired or single frontonasals; prefrontals paired or irregular, sometimes with a diamond shaped scale between frontonasal and prefrontals; interparietal usually bordered by a pair of parietals laterally, by a series of 3-9 smaller scales posteriorly; occipitals differentiated or not; temporal scales differentiated or not, irregular, sometimes keeled; rostral large, mental and postmental single, followed by several paired chin shields; gular crease feeble or absent. Collar fold moderately to well developed. Lower eyelid developed, with a palpebral disc divided into 3-6 scales, sometimes pigmented. Tympanum slightly to deeply recessed, overhung by surrounding scales of surface of head. Dorsal scales uniformly small, or heterogeneous, imbricate, with keeled tuberculate scales, sometimes intermixed with small flat or convex scales, in longitudinal, oblique, or transverse and oblique rows. Ventral scales usually flat, rounded posteriorly, imbricate, in transverse and 8–10 longitudinal rows, lateralmost rows convex or keeled in some species. Limbs pentadactyl, digits clawed; forefoot with enlarged, plate-like scales along inner margin between thumb and wrist; under side of third and fourth toes with paired scales proximally, inner scale a rounded tubercle. Tail strongly compressed; a double caudal crest, feebly to strongly developed. Femoral and preanal pores form an unbroken series: 32–72 in males; 1-18 in females. Preanal plate in 2-3 rows, posteriormost row with 5-7 scales in both sexes. Males and females with or without conspicuous, white-centred, black-bordered ocelli on their lateral body surfaces. Hemipenis without basal hooks; flounces without minute calcareous spinules.

Diagnosis: Neusticurus differs from members of Alopoglossinae by having its tongue covered in imbricate, scale-like papillae instead of oblique plicae (Harris, 1994), from Gymnophthalminae by having moveable eyelids, from Rhachisaurinae by having external ear openings, and from Ecpleopinae by having heterogeneous dorsal scalation. Within Cercosaurinae (sensu Castoe et al., 2004), Neusticurus differs from all genera except Echinosaura, Potamites and Teuchocercus by having heterogeneous dorsal scales.

KEY TO THE SPECIES OF POTAMITES GEN. NOV.

1a. Dorsal scales in longitudinal rows of large, keeled scales with smaller scales on either side of rows.................................................................................... 2

1b. No longitudinal rows of large, keeled dorsal scales....................................... P. strangulatus

2a. Single frontonasal scale.......................................................................... 3

2b. Frontonasal scale replaced by a series of irregular scales..................................... P. apodemus

3a. Tail annuli in complete rings of enlarged keeled scales................................................ 4

3b. Tail annuli rings not complete, large keeled scales interrupted by small flat scales......................... 5

4a. Tympanum at surface of the head......................................................... P. ocellatus

4b. Tympanum slightly recessed............................................................. P. cochranae

5a. Two to three reduced scales transversely between two paravertebral tubercular rows at mid-dorsum................................................................... P. juruazensis

5b. Four to six reduced scales transversely between two paravertebral tubercular rows at mid-dorsum.......................................................... P. ecpleopus

It differs from Echinosaura by lacking basal spines on the hemipenes, from Teuchocercus by lacking conical scales on the tail, and from Potamites (character states for Potamites in parentheses) by having a strongly compressed tail (slightly compressed), ventral scales imbricate (subimbricate ventral scales), and hemipenes lacking calcareous spinules on flounces (calcareous spinules on hemipenes).

Content: Neusticurus includes five species (Table 1).

Distribution: Neusticurus occurs throughout the Guianan Shield region of Venezuela, Guyana, Suriname, French Guiana, and northern Brazil.