Liolaemus montanezi, Cabrera, Mario R. & Monguillot, Julio C., 2006

Cabrera, Mario R. & Monguillot, Julio C., 2006, A new Andean species of Liolaemus of the darwinii Complex (Reptilia: Iguanidae), Zootaxa 1106, pp. 35-43 : 36-41

Liolaemus montanezi sp. nov.

( Figure 1 )

Type Material — Holotype: MACN 38746, an adult male collected at western margin of the Blanco river, 1.5 km S Quebrada Alcaparrosa, among this and the confluence of La Palca and Blanco rivers (29º 31’ 28” S, 69º 11’ 08” W), 2288 m above sea level, Parque Nacional San Guillermo, Iglesia Department, San Juan province, Argentina, 24 January 2005, by J. C. Monguillot.

Paratype: MACN 38747, an adult female, same data of collection as the holotype.

Diagnosis — Liolaemus montanezi sp. nov. is a member of the monophyletic boulengeri group of Liolaemus . Within the boulengeri group L. montanezi belongs to the darwinii complex, as defined by Etheridge (1993). The new species is a small (64 mm maximum SVL), long­tailed species (tail = 64–66% total length) with a relatively low number of scales around midbody (61–62); dorsal scales keeled; precloacal pores only in male, and a bulged patch of enlarged scales on the proximal posterior surface of the thigh in both sexes. It is distinguished from any other species of the darwinii complex by the lacking of light vertebral or dorsolateral stripes, as such or as zones lighter than background color. The male pattern consists of 12–13 pairs of dark paravertebral spots and irregularly scattered light blue and white scales “speckled” on reddish brown ground in head and body. The female pattern is dullest, also lacking of dorsal stripes.

Comparison with close species — Liolaemus montanezi differs from other members of the darwinii complex, except L. darwinii , L. grosseorum , L. laurenti and L. olongasta , in that adult male has black pigment within the pocket formed by the antehumeral fold. The lacking of both vertebral and dorsolateral stripes lighter than the background color, and its “speckled” pattern distinguish it from all these four taxa. Liolaemus montanezi further differs from L. darwinii by the lack of postscapular black spot, and from L. darwinii , L. laurenti and L. olongasta (unknown condition in female L. grosseorum ) by the absence of precloacal pores in the female of the new species. The number of midbody scales (61–62) in L. montanezi is comparatively higher than the means of L. laurenti (54.9) and L. olongasta (55.3) ( Etheridge 2001). Dark pigment is present on the throat and anterior chest of male L. montanezi , but not as the bold reticulation present in L. olongasta . Although the study of more specimens would have been desirable, this new taxon seems scarce or elusive. Its peculiar pattern, however, was present in other uncaptured individuals reinforcing its recognition as distinct.

Description of the holotype —MACN 38746, adult male ( Figure 1 ), 58 mm snoutvent length; complete, unregenerated tail 111 mm long. Head 1.26 times longer than wide. Snout slightly pointed in dorsal aspect. Dorsal head scales faintly rugose. Rostral two times wider than high, wider than mental, bordered behind by six postrostrals. Nasals anterodorsal in position; nostrils nearly circular, opening slightly dorsalad. Nasals medially separated by four internasals and from the rostral by two postrostrals each. Four postnasals on each side. Ten polygonal frontonasals, symmetrically arranged. Two hexagonal prefrontals. All internasals, prefrontals and frontonasals with several scattered scale organs. Two frontal azygous followed behind by two polygonal frontoparietals arranged side by side. Interparietal with a conspicuous pineal eye, bordered by six parietals: a small asymmetrical pair forward, one anterolateral scale on each side and about same size as the interparietal, and two—the biggermost—hexagonal scales by behind. Scales on occiput rounded, smooth, imbricate, arranged along seven or eight regular rows. Left supraorbital semicircle with 13 polygonal scales, right supraorbital semicircle some interrupted forward, accurate count impeded by some scaring in the middle of row. Thirteen swollen, faintly rugose supraoculars on each side, those medialmost transversely expanded. Supraoculars separated from superciliaries by one or two rows of small polygonal scales. Three canthals on each side, the foremost transversely expanded, the last one overlapping the first superciliar. The canthus rostralis includes the postnasal scale that contacts to lorilabials. Five elongate, obliquely overlapping superciliaries, followed by two shorter scales overlapping to fifth in the opposite direction. A single, short preocular followed by an elongate, some concave, curved subocular several times longer than high, overlapped near its posterior end by a thin postocular keeled along its medial axis. Palpebrals small, granular, juxtaposed. Ciliaries quadrangulars, projecting from the eyelid as a short “eyelash”. Loreals 5/6, smaller than lorilabials, in two rows, with two or three lenticular scale organs on each. Seven lorilabials longer than high, the first three on each side higher than supralabials; all with several scattered scale organs. Eight supralabials, the fourth and fifth the longest, all longer than high and with no evident scale organs. Temporals smooth, polygonal, convex, juxtaposed; most with one, more rarely two, scale organs near their posterior border. Aperture of external auditory meatus subrectangular with rounded corners, higher than long, bordered anteriorly by small higher­than­long scales, scarcely projecting outward, except for one scale anterodorsal to the meatus, notoriously larger than the others; meatus bordered posteriorly and below by small ovoidal scales. Mental subpentagonal with concave lateral sides, 1.5 times wider than long, bordered laterally by the first infralabial on each side and posteriorly by two large postmentals. Six infralabials on each side, with 1–3 scale organs each, near their border contacting to sublabials. Six pair of enlarged postmentals, only the first in medial contact, all others aparted from by convex, imbricated gulars. Only the first pair of postmental in partial contact with first infralabial, second pair separated from infralabials by one row of sublabials, the third to fifth pair by two rows, and the sixth by three rows of scales. Posterior gulars flat, imbricated.

Body slender. A skin fold out extended along both flanks, between fore and hindlimbs. Dorsal scales on neck blunt keeled, imbricated; some on dorsolateral neck and body, subimbricate. Dorsal scales on body ovate with rounded free margin, keeled all along their axis but not mucronate; keels forming continuous longitudinal streaks disrupted on tail dorsum. Scales around midbody 61; middorsal scales 69. Skin of lateral neck region irregularly and amply folded. Antehumeral fold distinct, pocket lined by tiny granular scales. Dorsal body scales grade gradually to the sides into smaller, faintly keeled scales; those on the lateral longitudinal fold, smooth and juxtaposed. Granular scales dorsally and posteriorly to forelimb insertion. Ventral body scales smooth, rhombic, larger than dorsals, imbricate. Scales on precloacal region, between hindlimb insertions and vent, slightly larger than ventrals. Six yellow precloacal pores.

Dorsal scales on both fore and hindlimbs keeled, imbricate. Infrabrachial scales conical, juxtaposed. Infra­antibrachial scales larger, smooth to weakly keeled, imbricate. Dorsal scales on manus smooth. Supradigitals smooth, wider than long. Palmar scales strongly keeled, mucronate, imbricate. Tricarinate, mucronate lamellae under digits; 23 under fourth left finger. Dorsal thigh scales keeled and imbricate, become gradually smaller, smooth and juxtaposed to posterior. Patch distinct, formed by 22–24 scales larger than the neighbours, faintly keeled but mucronate, imbricate. Thigh underside and infratibiofibular scales large, rhombic and smooth, imbricate. Scales on dorsum of pes large, imbricate; smooth, become gradually keeled to the posterodistal region between digits IV and V. Supradigitals smooth, larger than wide. Scales on sole of pes keeled, mucronate, some trifid, imbricate. Tricarinate, mucronate lamellae under digits; 30 under fourth left toe. Manus and pes with sharp, slender claws, equal in length to the span of 3–4 distal supradigital scales.

Tail long and slender, subcircular in section. Caudal scales in discernable annuli throughout all its length, less evident only on suprahemipenial portion. Dorsal and lateral caudal scales keeled, shortly mucronate. Ventral caudal scales smooth proximally, gradually keeled from the row 20, becoming keeled and mucronate.

Coloration —In life, dorsal ground color of head and body reddish brown; 12–13 pairs of darker paravertebral spots, hardly discernable from the ground, become more evident and wider on tail dorsum. Profusion of scales white and light blue irregularly scattered on head, body and tail dorsum. Middorsal and dorsolateral stripes absent as such or as lighter zones. Same ground color on limbs and tail, some lighter in the latter.

Lateral surfaces of head with subsymmetrical pattern of black bars, the foremost one passing accross the anterior angle of eye to sublabials; a bold second bar cross the middle of the eye, reaching the dark pigment on throat; a third, wide, bar cross the posterior angle of eye down to fuse to the pigment on throat. Except for these bars, the infraoculars, lorilabials and supralabials are whitish with sparse tiny dotting. A black line runs longitudinally on the temporals from behind the eye, fading before reach the ear. Infralabials and sublabials whitish, crossed by dark bars confluent with dark brown pigment on the throat. Mental, postmentals and gulars whitish with abundant dark dotting.

Pocket formed by antehumeral fold wholly lined in ink­black; a bar extending out from it to the forelimb insertion and another, more­or­less continued, to dorsal, then curved forward occupying several scales long. Posthumeral spot absent. On body flanks the ground color reaches to the longitudinal fold, being replaced ventrolaterally from there by white and grey scales with small dots. Sides of tail with grouped light blue scales.

On the limbs dorsum small spots white, black and light blue form irregular, disrupted bars. Posterodorsal surface of thighs with two parallel black stripes along the thigh axis, bordering above and below a white stripe. Femoral patch scales white, some of them with grey dotting.

Ventral surface of throat dark brown; anterior chest whitish with dark mottling gradually fading to venter, nearly totally white. Underside of forelimbs, hindlimbs and tail, white. In fixative the ground color shifts to greyish dark brown, and the light blue scales turn to grey. Pattern in the female much less marked than in male (see under Variation).

Variation —The only other known specimen of Liolaemus montanezi is the female paratype. Snout­vent length 64 mm; tail broken but complete, unregenerate, 114 mm length. Scales around midbody 62; middorsal scales 69. Precloacal pores absent. Supralabials 6/6, infralabials 6/6. Only one azygous frontal. Femoral patch nearly as developed as in male. Other pholidosis features (form, arrangement and keeling of scales, distribution of scale organs, infradigital lamellae) as in the male, except for scales on precloacal region, which in the female are rounded, nearly granular, juxtaposed and smaller than ventrals.

Coloration: Dorsal ground (in fixative) dark brown, with nearly complete absence of light scales. Dorsal dark markings present only as tiny dots, hardly noticeable, arranged in pairs at both sides of midline. On the tail dorsum these marks become wider and more evident on the ground. Dark head bars faint, that one across the middle of eye the most evident. Throat white speckled with grey. Prehumeral pocket lined in dull black, more­orless continuous to anterior and dorsal surfaces of limb insertion. The darker black pigment is limited to two spots, one dorsal to the antehumeral fold and other six scale rows foreward, at same level, dorsolaterally on the neck. Posthumeral spot absent. The black and white stripes on the posterodorsal surface of thighs more discontinuous than in male, but evident. Belly whitish, with yellowish iridiscence. Other underparts white.

Etymology —The specific epithet is a friendly homage to Mr. Alvaro Montañez, park guard Head of the Parque Nacional San Guillermo, by his encouragement and support to all research activities in that protected area.

Geographic distribution — Liolaemus montanezi is known only from the type locality.

Natural history — Liolaemus montanezi is terrestrial, dwelling on rocky gravel and sandy soil in a Monte vegetation landscape dominated by “jarilla” ( Larrea divaricata ), “retamo” ( Bulnesia retama ) and “lamar” ( Prosopis alpataco ). The vegetation in the capture site is sparse, with bare soil percentages above 70% ( Figure 2 ). This habitat is associated to the Blanco river, which meanders between mountains of 3500–4500 meters of altitude. The water runs between rocky banks, vegetation is present only on the higher portions of the banks. As a consequence of transport by water the bottom is rocky.

Liolaemus montanezi seems to have low population density. In several expeditions during last years by one of us (JCM) this lizard was seen infrequently, and in very low number (no more than five individuals of both sexes). The only other Liolaemus syntopic there with L. montanezi is a still undescribed species of the same complex, very different in pattern and coloration. The gekkonid lizard Homonota fasciata has been seen, but not collected.

Remarks — Liolaemus montanezi inhabits the Parque Nacional San Guillermo, core section of the Biosphere Reserve of San Guillermo, in San Juan province, one of the most important protected natural areas of Argentina in terms of represented ecosystems as well as in protected populations of fauna, e. g. the birds Fulica cornuta and Pterocnemia pennata garleppi and the camelid Vicugna vicugna, among others ( Haene et al. 2000). The Reserve is also rich in iguanid endemisms: Phymaturus punae , Liolaemus eleodori ( Cei et al. 1983) and several species under study and description by us and others. L. montanezi is probably endemic to the Reserve, which is rich in isolated spots surrounded by high cordilleras favouring speciation processes. Among the known members of the darwinii complex, the geographically closest is Liolaemus olongasta , collected out of the Reserve boundaries at Angualasto (30º 03’ S, 69º 09’ W) ( Etheridge 1993) about 55 km south of the terra typica of L. montanezi .

Figures

FIGURE 1. The holotype of Liolaemus montanezi, adult male, in life.

FIGURE 2. View looking toward the south at the habitat of Liolaemus montanezi. In the foreground, sparse bushes of Monte vegetation. Behind, the high slope that limits to south the Parque Nacional San Guillermo. The slopes of Sierra de los Médanos are seen in the far background.