Enyalioides praestabilis ( O'Shaughnessy 1881 )

Torres-Carvajal, Omar, Etheridge, Richard & Queiroz, Kevin De, 2011, A systematic revision of Neotropical lizards in the clade Hoplocercinae (Squamata: Iguania), Zootaxa 2752, pp. 1-44 : 27-29

Enyalioides praestabilis ( O'Shaughnessy 1881)

Proposed standard English name: Canelos woodlizards

Proposed standard Spanish name: lagartijas de palo de Canelos

Enyalius praestabilis O’Shaughnessy (1881:240) . Syntypes: BMNH 8.12.8.38 (RR 1946.8.9.15), 80.12.8.37, from (respectively) “Pallatanga [in error] and Canelos, Ecuador.” Pallatanga (Provincia Chimborazo, 1°59'S, 78°57' W, 2248 m) lies west of the Ecuadorian Andes, where this species does not occur. O’Shaughnessy and Boulenger list “Pallatanga and Canelos” as the type locality for several species of amphibians and reptiles collected by Buckley and purchased by the British Museum of Natural History; in all cases Pallatanga seems to be an error caused by specimen mislabeling ( Peters 1955). The type locality for E. praestabilis is herein restricted to Canelos [Provincia Pastaza, 1°34'60''S, 77°45'W, 631 m]. Enyalioides praestabilis Boulenger (1885:113) ; Burt & Burt (1931:267; 1933:25); Peters & Donoso-Barros (1970:115).

Diagnosis. Enyalioides praestabilis differs from all other species of Enyalioides , except for E. rubrigularis , in having the following combination of characters: caudals increasing in size posteriorly on each autotomic segment; ventrals smooth or feebly keeled; and projecting scales on dorsum and limbs absent. It can be distinguished from E. rubrigularis (character states in parentheses) by having smaller scales on the ventral surface of the thighs in males; gulars cream or yellow without black margins (gulars bright orange or red, with black margins); black patch covering gular fold and posteromedial portion of gular region in some male specimens (posteromedial aspect of gular region without black patch); and usually one femoral pore (normally two).

Description. (1) dorsal head scales conical or multicarinate, strongly projecting dorsally; (2) posterior superciliaries not enlarged relative to adjacent scales; (3) scales on lateral edge of skull roof just posterior to superciliaries usually (80%) more projecting than adjacent scales; the projection is more pronounced in adults; (4) one or two enlarged pretympanic scales present; (5) gular scales conical or multicarinate, strongly projecting ventrally, distinctly keeled on gular fold; (6) dorsal and lateral neck scales similar in size, mostly granular or conical; (7) vertebrals larger than adjacent dorsals, forming distinct raised middorsal crest that extends onto tail as a pair of crests; (8) nuchal region usually with continuous (95%) and single (80%) middorsal crest; (9) dorsals keeled and homogeneous in size; (10) longitudinal row of raised, enlarged scales between dorsals and flank scales usually (95%) present; when present this row is continuous; (11) scales on flanks granular, heterogeneous in size; Wiens & Etheridge (2003) reported only 25% of their specimens as having enlarged scales on flanks probably because the difference in size among flank scales in E. praestabilis is usually not as conspicuous as in other species of hoplocercines with heterogeneous flank scales (e.g., E. heterolepis ); (12) ventrals usually (85%) smooth; (13) fore limb scales keeled dorsally, keeled or smooth ventrally; (14) hind limb scales keeled dorsally and keeled or smooth ventrally; scattered enlarged scales usually (95%) absent; dorsal scales of pes homogeneous in size; (15) caudals heterogeneous, increasing in size posteriorly on each segment (5–8 scales in lateral view), not modified as conspicuous spines ( Fig. 3 ); (16) tail compressed laterally. Meristic and morphometric characters are presented in Table 1 .

Coloration in life ( Fig. 4 ). Adult males (KU 122117): dorsal background bright green with dark brown marks or black scales forming a reticulate pattern; dorsal surface of head mostly black with scattered green and bluishgreen scales; labials tinged with blue; scales on sides of neck sometimes pale blue; distinct white spot posterodorsal to tympanum; black patch on gular region; chest and throat adjacent to gular region tinged with yellow or pale orange; chin tan; ventral surfaces of body and limbs creamy tan or creamy orange; iris dark bronze or brown; tongue and lining of mouth pale pink (W.E. Duellman field notes [3 August 1968, 27 September 1974] and color photographs).

Juveniles (KU 122116): dorsal background dark olive-brown with scattered dark brown marks forming transverse bands on back and spots on flanks; dorsal surface of head with scattered bright green scales; sides of head bright green with dark brown marks; venter tan with dark brown flecks; iris copper (W.E. Duellman field notes [4 August 1968]).

Natural history. Specimens of Enyalioides praestabilis have been found sleeping at night on vertical trunks and branches less than 1.7 m above ground sometimes close to ponds or streams. A female (SVL = 101 mm; QCAZ 8826) collected in October 2003 in Provincia Morona Santiago, Ecuador, had three enlarged vitellogenic follicles on the left side (4.18–4.96 mm X 4.30–5.61 mm) and two on the right side (4.63–5.06 mm X 4.84–5.48 mm).

Distribution. Enyalioides praestabilis occurs east of the Andes in southern Colombia, Ecuador, and northern Peru ( Fig. 10 ) at elevations between 200-2000 m. This species is known to occur in sympatry with E. laticeps and E. microlepis in eastern Ecuador. However, these species also might be sympatric east of the Andes in southern Colombia and northern Peru.

Remarks. Except for two specimens (USNM 211156, 211158) males of Enyalioides praestabilis from populations north of 1°S have a black patch on the posteromedial aspect of the gular region, whereas males from populations south of this latitude lack this patch. This latitudinal boundary more or less corresponds with the Napo River, one of the main tributaries of the Amazon River, which might represent a geographical barrier separating these two sets of populations. The black gular patch (presence or absence) is a fixed character in other species of hoplocercines ( Wiens & Etheridge 2003), which suggests that E. praestabilis , as currently recognized, may consist of two species. If so, the name praestabilis would apply to the southern populations. Herein we favor the hypothesis that the northern populations do not represent a separate species for the following reasons: (1) the genetic distance between two specimens from both sides of the Napo river lies within the range of other intraspecific distances (Torres-Carvajal & de Queiroz 2009); (2) two adult male specimens (USNM 211156, 211158) from localities north of the Napo river lack the distinctive gular patch of northern populations; and (3) based on the other morphological features examined in this manuscript, northern and southern populations are indistinguishable. Though not evidence supporting either the single-species or the two-species hypothesis, the sister taxon relationship between two specimens of E. praestabilis from different sides of the Napo river was strongly supported (bootstrap value = 100) in a maximum likelihood analysis of mitochondrial DNA sequence data (Torres-Carvajal & de Queiroz 2009).

Figures

FIGURE 3. Caudal segments from the anterior third of the tail of ten species of Hoplocercinae in lateral view. (A) Enyalioides cofanorum, (B) E. heterolepis, (C) E. laticeps, (D) E. microlepis, (E) E. oshaughnessyi, (F) E. palpebralis, (G) E. praestabilis, (H) E. rubrigularis, (I) E. touzeti, and (J) Morunasaurus annularis. Scale bars = 5 mm. Illustration by D. Paucar.

FIGURE 4. Photographs of live lizards representing twelve species of Hoplocercinae.

FIGURE 10. Distribution of Enyalioides praestabilis (dots) and E. touzeti (triangles).