Dracaena Daudin

Harvey, Michael B., Ugueto, Gabriel N. & Gutberlet, Ronald L., 2012, 3459, Zootaxa 3459, pp. 1-156 : 136-137

Dracaena Daudin

Figure 76

Dracaena Daudin 1801: 421 . Type species Dracaena guianensis Daudin by monotypy.

Ada Gray 1825: 200 . Type species Teius crocodilinus Merrem (= Dracaena guianensis ).

Thorictis Wagler 1830: 153 . Type species Dracaena guianensis Daudin.

Diagnosis.— Dracaena is the only genus of Teiidae with subterminal lenticular scale organs positioned atop the prominently keeled ventrals and a complete interangular sulcus containing small granular scales. The combination of two loreals, a laterally compressed tail, and heterogeneous dorsals consisting of large keeled scales surrounded by smaller scales immediately distinguishes Dracaena from all other Teiidae .

Content.— Dracaena guianensis Daudin and Dracaena paraguayensis Amaral.

Definition.— Large lizards reaching 450 mm SVL ( Dracaena paraguayensis ); tail 1.6–1.7X as long as body; posterior maxillary and dentary teeth molariform; pupil round.

Prefrontals irregularly divided; frontal entire, lacking longitudinal ridge; posterior suture of frontal contacting second supraocular; scales of frontoparietal region smooth, outwardly convex to flat; key-hole shaped depression absent; frontoparietals paired; parietals consisting of three regular scales; interparietal entire, larger than flanking parietals; medial pair of enlarged occipitals absent; occipitals 10–12, larger than or subequal to scales in first row of dorsals; supratemporals slightly to moderately enlarged, separated from parietals by one or more scales.

Rostral groove absent; nostril subcircular to subtriangular, positioned slightly anterior to nasal suture; loreals two; supraoculars 8–11; first supraocular entire, smaller than fourth supraocular, in contact with or partially to completely separated from second supraocular by granular scales; circumorbital semicircles consisting of 0–6 small scales, restricted (when present) to posterior border of fourth supraocular; supraciliaries subequal, 23–28, separated from supraoculars by one row of 15–22 granular scales; first supraciliary in contact with first subocular or separated from it by small granular scales; suboculars 8–9, heavily fractured; first subocular separated from supralabials by scale inserted between suboculars and loreal; scales in front of auditory meatus distinctly enlarged; auricular flap and preauricular fold absent.

Supralabials 16–18; first supralabial smaller than second, its ventral margin straight; infralabials more numerous than supralabials, 20–24; first pair of chinshields completely separated from infralabials by small granular scales; first and second pairs of chinshields in medial contact; interangular sulcus complete, consisting of small granular scales; anterior gulars 19–25; gular patch absent; posterior gulars 6–9; intertympanic sulcus incomplete medially, with small granular scales on sides of gular region; larger anterior gulars not undergoing transition to smaller posterior gulars; mesoptychials not to slightly enlarged, not forming differentiated transverse row or serrated edge of gular fold.

Dorsals heterogeneous, large convex scales separated by smaller scales; dorsals keeled; large scales on flanks supported posteriorly by transverse fold of skin covered in tiny granular scales (i.e., instead of single apical granules); scales of chest large and flat; pectoral sulcus absent; ventrals keeled, in 29–33 transverse and 32–39 longitudinal rows; subrectangular scales lateral to ventrals gradually decreasing in size on flanks, bordering transverse folds of skin; preanals 4–6; preanal plate, preanal spurs, and postanal plates absent; postcloacal buttons present in males; tail with pair of dorsolateral crests; enlarged scales of crest heavily keeled and projecting away from tail at about 45°; accessory crests disposed in irregular rows at base of tail; complete caudal annuli alternating with annuli complete ventrally but divided on sides and dorsum of tail; proximal subcaudals keeled.

Preaxial, dorsal, and postaxial sides of brachium and antebrachium covered in scales longer than wide, noticeably enlarged series absent from arm (scales largest on preaxial and dorsal brachium and antebrachium, grading to granular scales postaxially); scales on proximal, ventral surface of antebrachium slightly enlarged; subdigital lamellae entire and sharply keeled distally, divided under penultimate phalanx, divided and separated by one or more small scales under more proximal phalanges, completely fractured into 7–8 small rounded scales arrayed in transverse rows under basal phalanx; 22–26 subdigital lamellae (including rows of fractured scales) under fourth finger.

Prefemorals not differentiated; femoral and abdominal pores 8–11 (1-2/1-2 femoral and 2–4/2–4 abdominal), each pore opening in center of single oval scale; 3–5 scales separating abdominal pore series medially; gap of about five granular scales separating femoral from abdominal pores; scales at heel relatively small and numerous; tibiotarsal spurs and shields absent; lamellae under fourth toe 35–38; distal lamellae of fourth toe sharply keeled; small granular scales separating digital lamellae along postaxial edge of each toe; 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, but not surpassing proximal free phalangeal articulation of fourth toe.

β- keratin containing layers folded into macrohoneycomb on all body surfaces (including ventrals); lenticular scale organs well developed, single, positioned subterminally atop keel of large dorsal scale on trunk and tail; scale organs present on ventrals; generation glands apparently absent.

Snout same color as dorsal head scales, head of adult Dracaena guianensis often bright reddish but this color not restricted to snout. In juveniles, light vertebral, paravertebral, dorsolateral, upper and lower lateral stripes absent; dark dorsolateral and lateral fields absent ( D. paraguayensis with large black or dark brown blotch side of neck in same position as lateral field); thigh lacking light spots (some adult specimens of D. paraguayensis with large pale blotches on flanks but lacking light spots or ocelli). In adult males, turquoise ventrolateral spots absent; venter immaculate or with brownish blotches, lacking large melanic areas or blotches in adult males; juvenile dorsal color pattern present in adult males with no or only minimum modification.

According to Cope (1896), hemipenis laminate and with asulcate expansion pleat (referred to as a “welt” opposite the sulcus by him, p. 465).

Etymology.— The generic name Dracaena is the Latin noun Dracaena meaning dragon or, less commonly, lizard. As discussed recently by Massary et al. (2000), Daudin (1801) based his description on the figure titled “La dragonne” and description of Lacerta dracaena by La Cepède (1788). Lacerta Dracaena also appears in Gmelin’s (1789) list along with a brief Latin description. Gmelin’s name would appear to be an available senior synonym of D. guianensis , albeit one that should be suppressed since it has not been used since the late 1700s.

Distribution.— Amazon Basin and Pantanal Region of Bolivia, Brazil, Colombia, Ecuador, French Guiana, Paraguay, and Peru.