Neusticurus racenisi ROZE, 1958
Can you confirm these amateur observations of Neusticurus racenisi?
|Higher Taxa||Gymnophthalmidae (Cercosaurinae), Sauria, Gymnophthalmoidea, Squamata (lizards)|
|Common Names||E: Common Venezuelan water teiid, Roze's Neusticurus|
S: Lagartijo acuático de Racenis, Maskani
|Synonym||Neusticurus racenisi ROZE 1958: 252|
Neusticurus racenisi — PETERS et al. 1970: 207
Neusticurus racenisi — AVILA-PIRES 1995: 436
Neusticurus racenisi — MYERS & DONNELLY 1997
Neusticurus cf. racenisi— BARRIO-AMOROS & BREWER-CARIAS 2008
|Distribution||Venezuela (Bolivar), Brazil (Roraima)|
Type locality: Auyantepui, Estado Bolivar, Venezuela.
|Types||Holotype: AMNH 61008|
|Diagnosis||Diagnosis. Neusticurus with short snout, tympanum deeply recessed within an external auditory meatus, lower eyelid with low-translucent disc of 4-8 palpebrals. Prefrontals, frontal and frontoparietals divided innumerous scales which formin part a pair of supraorbital semicircles. Back without prominent tubercles, although with some longitudinal rows of slightly enlarged scales; 101-129 (114.9 ± 9.8) scales along a vertebral line. Flanks with small scales. Ventrals i n 29-30 transverse rows. Tail compressed, with transverse rows of tubercles separated by 3-4 rows of smaller scales; only distally there is a low double dorsal crest. Verticils distinct on tail, with two transverse rows of ventral scales corresponding to 4-6 transverse rows of scales on the sides (Avila-Pires 1995).|
Description. Gymnophthalmid with maximum SVL in males of 104 mm (Uzzell, 1966), in females of 94 mm (MCZ 66933). Head 0.22-0.25 (0.24 ± 0.01, n= 6) times SVL, 1.5-1-7 (1.67 ± 0.09, n= 6) times as long as wide, 1.0-1.2 (1.10 ± 0.09, n= 6) times as wide as high. Snout bluntly pointed, rising gently toward top of head; supratemporal and gular regions may become swollen in adult males. Neck slightly narrower than head and body. Body cylindrical. Limbs well developed, forelimbs 0.32-0.35 (n= 3) times SVL, hind limbs 0.47-0.52 (n= 2) times. Tail compressed, tapering toward tip, 1.8-2.2 (n= 3) times SVL.
Tongue lanceolate, covered with imbricate, scale-like papillae, with a smooth, bifid tip. Anterior teeth conical, posterior teeth of upper jaw bicuspid, of lower jaw tricuspid.
Rostral rectangular or hexagonal, more than twice as wide as high, visible from above. Frontonasal either single or medially divided; when single it is relatively large and squarish (although slightly wider posteriorly); in holotype an irregular scale is split off in posterior corner of frontonasal. Prefrontals, frontal and frontoparietals divided in numerous scales, variable among specimens, but in general forming a group of five to thirteen relatively small scales medially on the snout, and two series of scales resembling the supraorbital semicircles of Iguanidae, at each side with from six to ten scales, ending in the larger parietal (included in the count). Interparietal slightly to distinctly longer than, and as wide as to distinctly narrower than parietals. Between interparietal and 'supraorbital semicircles' there may be one to three (or none) small scales. Interparietal and parietals bordered posteriorly by distinctly smaller, irregular scales, one row along parietals, two or three rows of more elongate scales behind interparietal. Posteriad these scales grade into smaller, conical, juxtaposed scales which occupy most of the occipital region and merge into scales on nape. Three or four enlarged supraoculars, when three they are preceded by a group of small scales, when four first is smallest and there may be other small scales together with it; small scales are also usually present as a group posteriorly, in a row at the border with supraciliaries, and isolated on medial border of supraocular area. Supra-ciliaries 6-9, mostly 7-8. Nasal undivided, nostril approximately in centre, directed lateroposteriorly. Loreal large, mostly single but longitudinally divided in M C Z 66933; in contact with supralabials. Frenocular present, continuous with a row of 3-5 longitudinally convex suboculars. Two rows of relatively small postoculars, anterior row with 6-8 scales, upper one largest, posterior row with 10-12 scales which dorsally reach the parietal. Lower eyelid with low-translucent disc of 4-8, usually five or six, palpebrals. Supralabials 6-7, four or five to below centre of eye, followed by three or four tapering postsupralabials. Temporal scales small, roundish to oval, convex, juxtaposed, slightly larger peripherally. Ear-opening vertically oval, with denticulate margins, especially anteriorly; tympanum deeply recessed within an external auditory meatus.
Mental about semicircular, although borders with each infralabial and with post-mental form two obtuse angles. Postmental pentagonal. Two or three pairs of chin-shields, all in contact with infralabials, first in contact medially. Three or four (five on one side of MCZ 62208) infralabials, posterior one below, or starting below, centre of eye. Chinshields bordered posteriorly by some relatively large, although distinctly smaller, scales; medially and posteriorly, scales smaller, elongate-hexagonal, convex, juxtaposed, in medially divergent rows. Gulars anteriorly shorter than posterior scales of chin (or pregulars), imbricate, in transverse rows; posteriad (from midventral line laterally) they become flatter, from irregular to squarish, gradually increasing in size. There are about 16-21 transverse rows of gulars, of which posterior 7-10 rows with enlarged scales, although no definite borders delimit pregulars, anterior and posterior gulars, and they more-or-less merge into each other. Collar distinct, with 6-10 scales; lateral borders may not be well defined.
Scales on nape anteriorly convex, tubercular, juxtaposed, in approximately transverse rows, posteriad gradually changing into dorsals. Scales on sides of neck similar or slightly larger. Dorsals relatively small, hexagonal, keeled, imbricate. Along vertebral line it is usually possible to distinguish two more-or-less regular rows of slightly enlarged scales, from somewhere on nape until base of tail, either in contact with each other or separated by smaller scales; 101-129 (114.9 ± 9.8, n= 7) scales along one of these rows between interparietal and base of tail. One or a few rows of enlarged scales, usually larger than vertebrals, dorsolaterally, from about forelimbs to base of tail. Flanks with small, hexagonal to squarish, convex to broadly keeled scales, in approximately transverse rows. Ventrals squarish with convex posterior margin, shortly imbricate, in eight or ten longitudinal,and 29 or 30 (n= 6) transverse rows; lateral longitudinal rows with narrower scales. Scales around midbody 52-66 (61.2 ± 5.4, n= 6). Preanal plate composed of three rows of smooth, slightly imbricate scales, larger posteriad, in some specimens bordered laterally by smaller scales; first row with 4-6 scales, second and third with 5-7 each. Preanal and femoral pores form a continuous row at each side, separated medially. Males with 62-72 (67.0 ± 4.8, n= 4) pores in total, including4-7 preanal pores at each side. In two females, one has 10 preanal pores, the other has a total of 12 pores, of which four at one side and five at the other are i n preanal position. Pores between two or three scales.
Tail proximally with transverse series of enlarged scales with prominent keels, the scales in paravertebral position either as large as, to larger than the others; each transverse row separated from next one by three or four rows of distinctly smaller scales. Distally only paravertebral rows continue, forming a paired dorsal crest, each enlarged scale separated from next one by two medially enlarged scales. Each enlarged scale on dorsal crest delimits the posterior border of a verticil, which corresponds laterally to 4-6 transverse rows of relatively small, feebly to distinctly keeled scales, larger on posterior row. On underside of tail, each verticil comprises two transverse rows of relatively large, squarish, smooth scales; these scales form several longitudinal rows near base, distally two longitudinal rows.
Upper arms with rhomboid or hexagonal, keeled, imbricate scales on their anterior and dorsal aspects, and smooth, rounded, convex, and juxtaposed scales on posterior and ventral aspects, with some gradation between them. Forearms with larger, irregular, smooth, imbricate scales anterodorsally, grading dorso-posteriorly into smaller, keeled scales, which become smooth on ventral side. Scales on thighs relatively large, irregular, smooth, shortly imbricate on ventro-anterior and ventral aspects; keeled and decreasing a bit in size on dorso-anterior aspect; and small, granular, posteriorly. Lower legs with one or two rows of larger, smooth, shortly imbricate scales along their anterior aspect, distinctly smaller, keeled scales on dorsal and posterior aspects, and a transition between these two types on ventral aspect. Lamellae under fingers single, smooth, transversely enlarged, 20-25 (22.5 ± 1.7, n= 11, 6 specimens) under fourth ringer; under toes partially divided, proximally internal half lamellae under third and fourth toes moderately tuberculate; 30-39 (34.5 ± 3.5, n= 7,4 specimens) under fourth toe (Avila-Pires 1995).
Color in life: A description of colour in life is given by Donnelly & Myers (1991), who observed sexual dimorphism in colour pattern. Their description agrees with the statement by Uzzell (1966: 284) that two mature males had bluish venters. A similar observation is seen on a label with MCZ 62208, made by its collector (J.A. Rivero) (Avila-Pires 1995).
Color in preservative: the three specimens from Roraima are completely bleached, so no pattern can be seen. The Venezuelan specimens are brown, uniformly or mottled with dark brown on head, with irregular dark brown spots along body and tail, and on limbs. In holotype, along flanks, there is a series of relatively large light brown round spots, with a narrow dark brown border; above this series another one with more irregular and a bit smaller, but otherwise similar, spots. Ventrally, head, most of gular region, and forelimbs mostly cream, laterally some scales may have darker spots; belly, hind limbs and tail dark grey in males, in females cream, with irregular dark spots under tail (Avila-Pires 1995).
|Comment||Synonymy: Uzzell (1966) erroneously considered N. racenisi to be conspecific with N. tatei. Van Devender (1967) recognized N. racenisi and N. tatei as separate species. Avila-Pires (1995) and Donnelly and Myers (1991) provided redescriptions of N. racenisi.|
|Etymology||Named after Dr. Janis Racenis (1915-1980), a Latvian entomologist, geographer, ornithologist, and ecologist who emigrated from the Ukraine to Venezuela and worked at the Institute of Tropical Zoology, Faculty of Sciences , Universidad Central de Venezuela.|