Ameivula, Harvey & Ugueto & Gutberlet, 2012

Harvey, Michael B., Ugueto, Gabriel N. & Gutberlet, Ronald L., 2012, 3459, Zootaxa 3459, pp. 1-156 : 93-99

Ameivula New Genus

Figure 61

Type Species.— Tejus ocellifer Spix by original designation.

Diagnosis.— Although the hemipenis of Ameivula ocellifera has at least one unique character (the papillate catchment folds and awns), hemipenes of other species in this genus have never been described and were unavailable for study. Ameivula differs from Ameiva (characters in parentheses) in having a long first supraciliary (shorter than second; but see remarks regarding species allied to A. litoralis where the first supraciliary is divided), the prefrontal usually contacting the nasal (separated from nasal), and the prefrontal separated from the first supraciliary (in contact, except in the A. lineolata series).

Content.— Ameivula abaetensis (Dias, Rocha, & Vrcibradic), Ameivula confusioniba (Arias et al.) , Ameivula cyanura (Arias et al.) , Ameivula jalapensis (Colli et al.) , Ameivula litoralis (Rocha et al.), Ameivula mumbuca (Colli et al.) , Ameivula nativo (Rocha, Bergallo, & Peccinni-Seale), Ameivula nigrigula (Arias et al.) , Ameivula ocellifera (Spix) , and Ameivula venetacauda (Arias et al.) .

Definition.—Small to medium lizards reaching about 85 mm SVL; tail about 1.9–2.4X as long as body ( Table 8); posterior maxillary and dentary teeth longitudinally compressed, tricuspid; pupil reniform.

follow ranges.

Prefrontal usually in contact with nasal, separated from first supraciliary; frontal entire, lacking longitudinal ridge, its posterior suture contacting third supraocular; scales of frontoparietal region smooth, outwardly convex to flat (key-hole shaped depression absent); frontoparietals paired; parietals consisting of five regular scales (rarely three, i.e., holotypes of Ameivula jalapensis and A. confusioniba and some specimens of A. littoralis, Roca et al. 2000 ); interparietal entire, larger to narrower than flanking parietals; medial pair of enlarged occipitals absent ( A. ocellifera and type specimens of A. confusioniba , A. cyanura , A. nigrigula , A. venetacauda ) or present (type specimens of A. abaetensis , A. jalapensis , and A. mumbuca ); occipitals 13–18, subequal to first row of dorsals; supratemporals slightly to moderately enlarged, separated from parietals by one or more scales.

Rostral groove present; nostril oval and oriented anteroventrally, positioned anterior to nasal suture; loreal single; supraoculars usually eight (6–10); first supraocular entire, larger than fourth supraocular, contacting ( Ameivula ocellifera , types of A. abaetensis , A. confusioniba , A. nigrigula , A. venetacauda ) or separated from (types of A. cyanura , A. jalapensis , A. mumbuca ) second supraocular; circumorbital semicircles consisting of 21–35 scales (15 in illustration of type of A. littoralis ), usually extending to posterior margin of first supraocular; supraciliaries 10–14, separated from supraoculars by 1–2 rows of 26–56 granular scales; first supraciliary long ( A. confusioniba , A. mumbuca , A. nativo , A. nigrigula , A. jalapensis , and A. ocellifera ) and greater than one-half length of second or divided ( A. abaetensis , A. litoralis , and A. venetacauda ) so that third supraciliary longest; angulate keel extending from first subocular to elongate subocular below eye; suboculars four; first subocular contacting or separated from first supraciliary, separated from supralabials by second subocular; patch of distinctly enlarged scales in front of auditory meatus; auricular flap and preauricular fold absent.

Supralabials 10–14; first supralabial usually smaller than second, its ventral margin “toothy”; infralabials 10–12; first pair of chinshields broadly contacting infralabials or partially separated from them by row of granular scales, forming medial suture greater than or equal to half their length; interangular sulcus absent; anterior gulars 14–22; gular patch absent; posterior gulars 9–14; intertympanic sulcus absent; larger anterior gulars undergoing sharp transition to smaller posterior gulars at intertympanic crease; mesoptychials moderately enlarged; gular fold lacking serrated edge.

Dorsals smooth; scales on flank subequal to middorsals, not projecting laterally, supported by small apical granules; scales on rump much smaller than proximal subcaudals; scales of chest large and flat; pectoral sulcus absent; ventrals smooth, in 27–32 (24–38 in species not examined by us, Arias et al. 2011a,b) transverse and eight ( Ameivula jalapensis , A. mumbuca , A. nativo , A. nigrigula , A. ocellifera ; possibly 6–8 according to Arias et al. 2011a,b, whose method of counting ventrals may differ from ours) or 8–10 ( A. abaetensis , A. cyanura , A. venetacauda , A. littoralis ) longitudinal rows; lateral-most ventrals flanked by small scales (i.e., ventrals not gradually decreasing in size on flanks); preanals 4–5; preanal plate present, bordered by subtriangular scales; preanals one-half as large to larger than scale anterior to them; preanal spurs, postcloacal buttons, and postanal plates absent; scales on dorsolateral edge of tail like those on top and sides, denticulate edge and dorsolateral crests absent; caudal annuli complete; proximal subcaudals smooth.

Enlarged scales of brachium connected by continuous band of subtriangular plates on dorsal surface of arm; preaxial and postaxial brachial scales 1.5–2X as wide as long, both extending proximally to or beyond center of arm; antebrachial scales enlarged and smooth, narrowly separated from or in continuous row with preaxial brachial scales; postaxial antebrachial scales slightly enlarged; subdigital lamellae of hand homogeneous in size, 14–20 (13–24 in specimens not examined by us; Arias et al. 2011a,b) under fourth finger.

Prefemorals 4–5; femoral and abdominal pores 12–45 in continuous row on each side (abdominal pores not separated from femoral pores by gap); each compound pore-bearing scale consisting of partially fused prefemoral or abdominal scale and 2–6 granular scales; 1–3 (usually 2) scales separating right and left pore rows; scales at heel relatively small and numerous; tibiotarsal shields absent; tibiotarsal spurs present in some populations of Ameivula ocellifera and in A. abaetensis , A. cyanura , A. litoralis , and A. venetacauda ; lamellae under fourth toe 25–34 (24–38 in species not examined by us; Arias et al. 2011a,b); distal lamellae of fourth toe smooth; scales between subdigital and supradigital lamellae of toes small and mostly restricted to phalangeal articulations; noticeably enlarged postaxial scales between fourth and fifth toe absent; fifth toe shortened, base of its claw not passing level of skin between third and fourth toes when adpressed.

β- keratin containing layers of dorsal scales folded into macrohoneycomb; dorsal and caudal scales with one subterminal lenticular scale organ; ventrals lacking scale organs; generation glands absent.

Snout same color as dorsal head scales, males of some populations currently assigned to Ameivula ocellifera with reddish heads and throats but color not restricted to snout. In juveniles (color of juvenile A. confusioniba and A. venetacauda unknown), light vertebral stripe absent ( A. jalapensis , A. mumbuca , A. nigrigula , A. ocellifera ) or solid and straight ( A. cyanura , A. littoralis ), or present only from mid-dorsum to sacrum ( A. abaetensis ); light paravertebral stripes present though often broken ( A. cyanura , A. jalapensis , A. littoralis , A. mumbuca , A. nigrigula , A. ocellifera , some specimens of A. abaetensis ) or absent (some specimens of A. abaetensis , some populations currently assigned to A. ocellifera ); dark dorsolateral field solid ( A. jalapensis , A. littoralis , A. mumbuca , A. nigrigula , some populations assigned to A. ocellifera ), solid and broken into blotches posteriorly (some populations of A. ocellifera ), or absent ( A. abaetensis , A. cyanura ); dorsolateral light stripe solid and extending to tail; dark lateral field solid ( A. abaetensis , A. cyanura , A. jalapensis , A. littoralis , A. nativo ) or with light spots ( A. mumbuca , A. nigrigula , A. ocellifera ); upper lateral light stripe solid and extending to groin; lower lateral light stripe broken ( A. jalapensis , A. littoralis , A. mumbuca , A. nativo , A. nigrigula , A. ocellifera ) or absent/ faded ( A. abaetensis , A. cyanura ); thigh lacking light spots, with some light marbling but not spots in A. littoralis ; lacking spots on flanks. Adult males with ( A. ocellifera , A. nigrigula ) or without ( A. abaetensis , A. confusioniba , A. cyanura , A. jalapensis , A. littoralis ; A. mumbuca , A. venetacauda ) turquoise ventrolateral spots; venter immaculate, lacking melanic areas in adult males (most species) or with black throat ( A. nigrigula ).

Hemipenis (based on Ameivula ocellifera ) with pair of taβ- like apical awns; awns and catchment folds papillate; apical papillae and apical basin absent; asulcate expansion pleat well-developed, interrupting about seven distal laminae; discontinuous distal laminae four on sulcate side; no laminae proximal to expansion pleat; basal papillae absent.

Etymology.— The new name Ameivula is a feminine noun in the nominative singular and a diminutive form of Ameiva . Arias et al. (2011a,b) did not state whether their new specific epithets (confusionibus, cyanurus, and venetacaudus ) are adjectives or nouns in apposition. We consider these names to be adjectives and accordingly emend them to agree in gender with the feminine genus Ameivula .

Distribution.— Cis-Andean lowlands south of the Amazon in Argentina, Bolivia, Brazil, and Paraguay.

Remarks.— Most species of Ameivula have only recently been described through revisions of the A. ocellifera complex, and many species have not reached museums outside of Brazil. Although we refer to our specimens as A. ocellifera , the ten specimens coded for phylogenetic analysis likely comprise three species: one from Bahia, another from Mato Grosso, and a third from the Chaco of Bolivia and Paraguay. Conceivably, all three could be undescribed. We base this assertion on presence/absence of tibiotarsal spurs and variation in other characters assessed in this study. Many of our characters were not assessed in recent descriptions of species in this genus. Thus, our definition is based primarily on the three species we examined and data gleaned from photographs and descriptions of other species not available for study.

Although similar in many ways to Ameiva , most species of the former Cnemidophorus ocellifer Complex are placed in the new genus Ameivula based on the long first supraciliaries of most species, small size, distinctive spinules on the apex of the hemipenis of A. ocellifera , and phylogenetic analyses of morphological (this study) and molecular data (Giugliano 2009; Giugliano et al. 2006). Unlike all Ameiva except for the A. lineolata series, species of Ameivula have the prefrontal separated from the first supraciliary and most specimens have the prefrontal in contact with the nasal. The prefrontal is separated from the nasal in the holotype of A. mumbuca and variation in this character remains unreported for this species ( Colli et al. 2003). Nonetheless, these scales were also separated in one specimen of A. ocellifera from Paraguay and low levels of polymorphism in this character should not come as a surprise.

Among the species of Ameivula, Arias et al. (2011a , b) recognized two “subgroups.” Specimens in their samples of A. confusioniba , A. mumbuca , A. nigrigula , A. jalapensis , and A. ocellifera lacked tibiotarsal spurs and had an enlarged scale behind the fourth subocular, five supraciliaries, ventrals in 6–8 longitudinal and 24–29 transverse rows, and 11–21 femoral pores. In contrast, specimens of A. abaetensis , A. cyanura , A. littoralis , and A. venetacauda lacked an enlarged scale behind the fourth subocular and had tibiotarsal spurs, 6–7 supraciliaries, ventrals in 8–10 longitudinal and 29–38 transverse rows, and 21–45 femoral pores. Ameivula nativo is a unisexual species that likely formed through hybridization involving a member of each group, A. ocellifera and A. abaetensis being the most likely candidates ( Dias et al. 2002).

This publication appeared after we had returned about half of the specimens of Ameivula ocellifera . However, we could not confidently assign the 10 specimens coded for phylogenetic analysis or two additional specimens to either subgroup defined by Arias et al. (2011a,b). Arias et al. (2011a) illustrate an enlarged temporal scale positioned behind the suboculars and bordering the rictal fold. Apparently, this scale varies somewhat in size even in their material: it is almost as large as the fourth subocular in a specimen of A. ocellifera illustrated in their figure 9, but only about half as large and longitudinally divided on the right side of the type of A. confusioniba (their figure 3). According to Arias et al. (2011a,b), species of the A. ocellifera subgroup have this enlarged scale but lack tibiotarsal spurs. Arias et al. (2011a,b) found concordance in these characters among their samples (species with spurs lack the enlarged scale), however we did not. Among the 12 specimens at hand, only one (AMNH 36375 from Bahia, Brazil) has the enlarged scale, however, this male specimen has well-developed tibiotarsal spurs. On the other hand, five specimens from Mato Grosso (3 males, 2 females) lack both tibiotarsal spurs and the enlarged temporal scale. Some of the specimens from Mato Grosso have an unusually large fourth subocular; possibly, the fourth subocular and enlarged temporal have fused in this population. A specimen from Bolivia, the specimen from Bahia, and five specimens from Paraguay have tibiotarsal spurs, yet they lack other characters of the A. littoralis subgroups (i.e., they have fewer than 21 femoral pores, long entire first supraciliaries, 27–31 transverse rows of ventrals, 8 longitudinal ventral rows).

The “subgroups” of Arias et al. (2011a,b) may be natural. Some characters of coloration such a light vertebral stripe (present in the Ameivula littoralis subgroup, absent in the A. ocellifera subgroup) and a blue tail (present in the A. littoralis subgroup, absent in the A. ocellifera subgroup) also appear to support recognition of these groups. Nevertheless, some of the characters used to define these groups such as tibiotarsal spurs and enlarged temporals are more variable than originally thought. Color characters are unknown for juveniles of some species. The divided first supraciliary in the Ameivula littoralis subgroup would appear to ally its members ( A. abaetensis , A. cyanura , A. littoralis , and A. venetacauda ) with Ameiva . These four species should be assessed for additional characters to test whether they should be retained in Ameivula , transferred to Ameiva , or placed in a third, unnamed genus. Although we formally define species groups of Ameiva and Cnemidophorus in this publication, we are hesitant to formally recognize these subgroups until contradictory character evidence can be investigated.