Contomastix, Harvey & Ugueto & Gutberlet, 2012

Harvey, Michael B., Ugueto, Gabriel N. & Gutberlet, Ronald L., 2012, 3459, Zootaxa 3459, pp. 1-156 : 112-115

Contomastix New Genus

Figure 67

Type Species.— Cnemidophorus vittatus Boulenger by original designation.

Diagnosis.— We know of no single unique character that distinguishes Contomastix from all other teiids. The tail of species in this genus is shorter than that of other Teiinae . These small teiids are most likely to be confused with Ameivula . Unlike species in that genus (characters in parentheses), Contomastix has a short tail (long), three parietals (five), a straight to curved ventral margin of the first supralabial (toothy), the first supralabial subequal to the second (much smaller than second), three relatively large scales at the heel (scales small and numerous), and a well-developed fifth toe (fifth toe reduced).

Contomastix was previously confused with Cnemidophorus . Unlike the species in this genus, male Contomastix lack preanal spurs (spurs present) and the species in this genus have the nasal and prefrontal in contact (separate), three parietals (five), homogeneous subdigital lamellae of the hand (subarticular lamellae of hand divided), and lamellae in contact along the postaxial sides of the toes (serrate row of keeled scales completely separating digital lamellae of toes).

Content.— Contomastix charrua (Cabrera & Carreira) , Contomastix lacertoides (Duméril & Bibron) , Contomastix leachei (Peracca) , Contomastix serrana (Cei & Martori) , Contomastix vacariensis (Feltrim & Lema) , Contomastix vittata (Boulenger) .

Definition.—Small lizards reaching 76 ( Contomastix vittata ) mm SVL; tail 1.6–2.1X ( Table 12) as long as body; posterior maxillary and dentary teeth longitudinally compressed, tricuspid; pupil reniform.

Prefrontal in contact with nasal, usually separated from first supraciliary; frontal entire (except some Contomastix vittata ), lacking longitudinal ridge, its posterior suture contacting second (most C. lacertoides ) or third ( C. serrana , C. vittata ) supraocular; scales of frontoparietal region smooth, outwardly convex to flat (keyhole shaped depression absent); frontoparietals paired; parietals consisting of three (rarely five) regular scales; interparietal entire, smaller to larger than flanking parietals; medial pair of enlarged occipitals absent; occipitals 9–17, larger than or subequal to first row of dorsals; supratemporals slightly to moderately enlarged, separated from parietals by one or more scales.

Rostral groove present; nostril oval ( Contomastix serrana , C. vittata ) to subcircular ( C. lacertoides ), oriented anteroventrally, anterior to nasal suture, touching suture ( C. vittata ) or not ( C. lacertoides , C. serrana ); loreal single; supraoculars six (rarely eight); first supraocular entire, larger than fourth (when present) supraocular, and broadly contacting or partly separated from (rarely completely separated from) second supraocular; circumorbital semicircles consisting of 4–8 small scales, usually extending anterior to point medial to third supraocular (rarely behind third supraocular); supraciliaries 10–15, separated from supraoculars by 1–1.5 rows of 18–38 granular scales; first supraciliary long, greater than one-half as long as second; angulate keel extending from first subocular to elongate subocular below eye; suboculars 4–6 (usually 4); first subocular contacting or separated from first supraciliary, contacting supralabials, entire (except in some C. vittata ); patch of distinctly enlarged scales in front of auditory meatus; auricular flap and preauricular fold absent.

Supralabials 12–14; first supralabial smaller than ( Contomastix serrana ) to subequal to ( C. lacertoides , C. vittata ) second, its ventral margin curved; infralabials 10–13; first pair of chinshields broadly contacting infralabials or partially (rarely completely) separated from infralabials by row of granular scales; chinshields medially separated from one another or forming a suture of variable length; interangular sulcus absent; anterior gulars 13–20; gular patch absent; posterior gulars 9–15; 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 30–36 transverse and ten 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 ( Contomastix vittata ) or keeled ( C. lacertoides , and C. serrana ).

Enlarged scales of brachium connected by continuous band of enlarged subtriangular plates on dorsal surface of arm; preaxial brachial scales 1.5–2X as wide as long, extending proximally to or beyond center of arm; postaxial brachial scales restricted to small patch near elbow, usually 1–1.5X as wide as long (frequently longer than wide in Contomastix vittata ); antebrachial scales enlarged and smooth, narrowly separated from or in continuous row with preaxial brachial scales; postaxial antebrachial scales slightly enlarged; lamellae under fourth finger 12–16; subdigital lamellae of hand homogeneous.

Prefemorals 5–8; femoral and abdominal pores 16–26, 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; 3–4 ( Contomastix serrana , C. vittata ) or 6–9 ( C. lacertoides ) scales separating right and left pore rows; three relatively large, subequal scales at heel; tibiotarsal shields and spurs absent; lamellae under fourth toe 19–30; 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 well-developed, base of its claw extending beyond 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. In juveniles, light vertebral stripe absent; light paravertebral stripes present and broken ( Contomastix vittata ) or absent ( C. lacertoides , C. serrana , C. vacariensis ); dark dorsolateral field completely broken into blotches ( C. lacertoides , C. vacariensis ) or solid anteriorly and broken into blotches posteriorly ( C. serrana , C. vittata ); dorsolateral light stripe solid and extending to tail (most species) or broken into spots ( C. vacariensis ; may be broken at some point along length in some specimens of C. lacertoides but most of stripe solid); dark lateral field solid ( C. serrana ) or completely broken into dark blotches ( C. lacertoides , C. vacariensis , C. vittata ); upper and lower lateral light stripes broken and extending to groin ( C. lacertoides , C. vacariensis ) or upper stripe solid and lower fading toward groin ( C. serrana , C. vittata ); thigh with light spots ( C. vacariensis ) or marked by light stripes ( C. lacertoides , C. serrana , C. vittata ). Adult males without light spots or ocelli on flanks; turquoise ventrolateral spots absent; venter immaculate, lacking melanic areas; juvenile dorsal color pattern present in adult males with only slight modification.

Hemipenis (based on Contomastix vittata ) with pair of taβ- like and smooth apical awns; apical papillae and apical basin absent; asulcate expansion pleat well-developed, interrupting 18–19 distal laminae; discontinuous distal laminae absent; 14–15 laminae proximal to expansion pleat; basal papillae absent.

Etymology.— Contomastix is a feminine noun in the nominative singular derived from the Greek adjective kontos, meaning short, and noun mastix, meaning whip. The name alludes to the relatively short tails of Contomastix compared to other whiptail lizards.

Distribution.— The six species of Contomastix occur in Argentina, Uruguay, southeastern Brazil, and the Andes of Bolivia. Reports of “ Cnemidophorus lacertoides ” from eastern Bolivia in the Serranía de Santiago ( Dirksen & De la Riva 1999) were based on misidentified specimens of Teius teyou and Ameiva ameiva in the FMNH. Known only from Cabo Polonio, Uruguay, C. charrua is thought to be extinct ( Cabrera & Carreira 2009). Interspecific Relationships.— In our phylogenetic analysis, Contomastix is not monophyletic. Contomastix lacertoides is placed outside of a clade containing C. serrana and C. vittata . Contomastix lacertoides differs considerably from these congeners. Unlike them (character in parentheses), C. lacertoides has a subcircular nostril (oval), frontal suture contacting the second supraocular (third), 6–9 scales separating the left from the right femoral pore rows (3–4), dark dorsolateral fields completely broken into blotches (solid anteriorly), and lower lateral stripe broken to groin (solid and fading). We have not seen the hemipenis of C. lacertoides , however Böhme (1988) mentions apical papillae in this species, whereas these structures are clearly absent from the hemipenis of C. vittata .

Recent authors ( Cabrera & Carreira 2009; Cei & Martori 1991; Cei & Scrocchi 1991; Feltrim & Lema 2000) have generally thought that Contomastix charrua , C. lacertoides , C. leachei , and C. vacariensis are closely related. Additional research is required to determine if the distinctive characters of C. lacertoides exclude it from Contomastix . We prefer to retain this species in Contomastix for the time being.