Enyalioides laticeps ( Guichenot 1855 )

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 : 19-22

Enyalioides laticeps ( Guichenot 1855)

Proposed standard English name: broad-headed woodlizards

Proposed standard Spanish name: lagartijas de palo de cabezonas

Enyalus laticeps Guichenot (1855:20) . Holotype: MHNP 6821, from “Fonteboa, upper Amazon, Brazil ”; Duméril (1856:529). Enyalus planiceps Guichenot (1855:21) . Syntypes: MHNP 6822, 6822a, from “Fonteboa, upper Amazon, Brazil,” synonymy fide Boulenger (1885:113).

Enyalius coerulescens Cope (1876:169) . Holotype: ANSP 11382, no specific type locality given, restricted to “the Amazon from Santarem to Peru ” ( Gans & Vanzolini 1953), synonymy fide Peters & Donoso-Barros (1970:115) upon suggestion of Gans & Vanzolini (1953:127).

Enyalius caerulescens Boulenger (1885:120) ; Burt and Burt (1933:25). Misspelling of Enyalius coerulescens ( Cope 1876) . Synonymy fide Peters & Donoso-Barros (1970:115) upon suggestion of Gans & Vanzolini (1953:127).

Enyalioides laticeps Boulenger (1885:113) ; Burt & Burt (1930:9; 1931:266; 1933:24); Peters & Donoso-Barros (1970:114).

Enyalioides festae Peracca (1897:3) . Syntypes: MZUT 2169, MSNG 36123, from “valley of Rio Santiago, Ecuador,” synonymy fide Burt & Burt (1931:228).

Enyalioides laticeps laticeps Burt & Burt (1930:9; 1933:24); Peters & Donoso-Barros (1970:115). Subspecies rejected by Avila-Pires (1995:30).

Enyalioides laticeps festae Burt & Burt (1931:228; 1933:24); Peters & Donoso-Barros (1970:115). Subspecies rejected by Avila-Pires (1995:30).

Diagnosis. This species can be distinguished from other species of Enyalioides by having caudal scales that are relatively homogeneous in size on each caudal segment; in all other species of Enyalioides , the dorsal and lateral caudals increase in size posteriorly on each caudal segment, and the largest (posteriormost) caudals are mucronate or have some kind of projection ( Fig. 3 ). In addition, most male specimens of E. laticeps have a longitudinal white, cream, or orange stripe 2–3 scales wide that extends from the commisure of mouth to a point below the tympanum ( Fig. 4 ).

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 sometimes (50%) slightly 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; (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 only onto anterior end of tail as a pair of indistinct crests; (8) nuchal region with continuous, single middorsal crest; (9) dorsals distinctly keeled and homogeneous in size; (10) longitudinal row of raised, enlarged scales between dorsals and flank scales rarely (16.7%) present; when present this row is continuous; (11) scales on flanks granular, homogeneous in size, and slightly smaller than dorsals; (12) ventrals usually (71.4%) keeled; (13) fore limb scales keeled dorsally and ventrally; (14) hind limb scales keeled dorsally and ventrally; scattered enlarged scales absent; dorsal scales of pes homogeneous in size; (15) caudals homogeneous (i.e., caudal segments inconspicuous), not increasing considerably in size posteriorly on each segment (6–8 scales in lateral view), not modified as conspicuous spines ( Fig. 3 ); (16) tail nearly circular in cross section. Meristic and morphometric characters are presented in Table 1 .

Coloration in life ( Fig. 4 ). Dorsum and flanks green (various tones) or brown, usually with irregular, scattered light spots, or a reticulate brown or reddish-brown pattern; some specimens with a diagonal light bar on the scapular region; longitudinal white, cream, or orange stripe 2–3 scales wide extending from the commisure of mouth to a level below the tympanum in some male specimens; lips and chin pale green is some specimens; gular region in males with longitudinal brown, reddish-brown, bluish, or orange streaks, and a large brown or black medial blotch at the level of the gular fold; gular region in females usually cream or reddish cream without streaks or blotches; venter orange in adult males and pinkish tan or cream in females, with a longitudinal series of dark brown or black short bars or streaks laterally in some specimens; iris brown with yellow or greenish yellow ring around pupil ( Duellman 1978, 2005; Avila-Pires 1995; Vitt & de la Torre 1996). Juveniles pale green or tan with brown diagonal marks on body, white throat, and creamy-tan venter ( Duellman 1978). Similar to other species of Enyalioides , E. laticeps displays metachromatism consisting of replacing green with brown tones when disturbed.

Natural history. This species is more abundant in primary than secondary forests; during the day it has been observed mostly on trunks of small trees with diameters less than 15 cm, whereas at night it usually sleeps horizontally on branches or palm fronds 1.5 m or more above ground ( Duellman 1978). This species uses crypsis as the main predator avoidance mechanism, although some individuals run away to hide under logs or in holes in the ground ( Dixon & Soini 1986; Vitt & de la Torre 1996). Prey items of Enyalioides laticeps consist mostly (70.4%) of spiders, caterpillars, and beetle larvae ( Duellman 1978); other common prey items include grasshoppers, crickets, and earthworms (Vitt & de la Torre 1996). Clutch size varies between 5– 7 eggs 15.0– 16.6 mm long ( Duellman 1978; Vitt & de la Torre 1996); females with 10–11 oviductal eggs were found between April-August ( Dixon & Soini 1986).

Distribution. Enyalioides laticeps occurs throughout the western Amazon basin at elevations between 80– 1600 m in Colombia, Ecuador, Peru, and Brazil ( Fig. 6 ); it might also occur in Bolivia ( Langstroth 2005). This species is known to occur in sympatry with E. cofanorum , E. microlepis , E. praestabilis in Ecuador and E. palpebralis in southern Peru. Given its wide distribution, E. laticeps is most likely sympatric with these species throughout most of their distributions. Similarly, E. laticeps might be sympatric with Morunasaurus annularis and M. peruvianus .

Remarks. Torres-Carvajal & de Queiroz (2009) found strong support (bootstrap value = 100) for the monophyly of Enyalioides laticeps in a maximum likelihood phylogenetic analysis of mitochondrial DNA sequence data that included two specimens from Ecuador, one from Peru, and another one from Brazil. Sequences of the individuals from Peru and Brazil were more similar to each other (maximum-likelihood corrected distance = 0.049) than they were to either of the two samples from Ecuador (0.069–0.081), which, likewise, were more similar to each other (0.017).

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 6. Distribution of Enyalioides heterolepis (triangles) and E. laticeps (dots).