Liolaemus cinereus, Monguillot, Julio C., Cabrera, Mario R., Acosta, Juan C. & Villavicencio, Jose, 2006

Monguillot, Julio C., Cabrera, Mario R., Acosta, Juan C. & Villavicencio, Jose, 2006, A new species of Liolaemus (Reptilia: Iguanidae) from San Guillermo National Park, western Argentina, Zootaxa 1361, pp. 33-43 : 34-40

Liolaemus cinereus sp. nov.

( Figures 1–3 )

Type material. Holotype: MLP.R 5139, an adult male collected at the flood plain of the northern margin of the Blanco River, Quebrada Alcaparrosa (29 º 30 ’ 47.5 ’’ S, 69 º 10 ’ 27.3 ’’ W), 2270 m above sea level, southern section of the San Guillermo National Park, Iglesia Department, San Juan province, Argentina, February 11, 2005, by J. C. Acosta and J. H. Villavicencio.

Paratypes: MLP.R 5140, an adult female, same data of collection as the holotype; MACN 38798 and 38799, two adult females collected 1.5 km S Quebrada Alcaparrosa, among this and the confluence of La Palca and Blanco rivers (29 º 31 ’ 28 ” S, 69 º 11 ’ 08” W), 2288 m above sea level, San Guillermo National Park, Iglesia Department, San Juan province, Argentina, January 24, 2005, by J. C. Monguillot.

Diagnosis. Liolaemus cinereus sp. nov. is a small iguanid lizard (63 mm maximum SVL in females), with a relatively long tail (57 % of total length) and low number of scales around midbody (58–62); dorsal scales moderately keeled; precloacal pores only in males; a bulged patch of enlarged scales on the proximal posterior surface of the thigh in both sexes, more evident in males; lacking of light vertebral or dorsolateral stripes; ash-grey dorsal background color with small transverse brown spots in two paravertebral series, and white scales roughly ordered on the trunk; antehumeral fold without black pigment (only faint greyish in the male, absent in females); scapular region pattern represented only by a prescapular dark spot dorsal to the antehumeral fold; throat and ventral neck brown in males; white, slightly dotted, in females. The new species is a member of the monophyletic boulengeri group of the genus Liolaemus . Within this group L. cinereus belongs to the darwinii complex, as defined by Etheridge (1993).

Comparison with related species. Liolaemus cinereus differs from any other species of the boulengeri group, except for those in the darwinii complex, in having moderately cusped, straight-sided to slightly expanded crowns in their posterior marginal teeth. Within the darwinii complex, the new species differs from L. darwinii , L. grosseorum , L. laurenti , L. montanezi and L. olongasta in lacking intensely black pigment within the antehumeral fold, and by its different dorsal pattern. It differs from L. abaucan and L. koslowskyi in lacking large postscapular spot, and from L. albiceps by its smaller body (up to 94 mm maximum SVL in males of the latter). Liolaemus cinereus further differs from L. albiceps , L. darwinii , L. irregularis , L. olongasta and L. ornatus (unknown condition in female L. grosseorum ) by the absence of precloacal pores in females of the new species. The new species differs from L. calchaqui by the absence of dorsolateral whitish stripes, invariably present in males of the latter, and by having more middorsal scales, both in male and females (68 vs. 63, and 67–71 vs. 58–64, respectively). It differs from L. quilmes by the absence of bold, symmetrical dorsal pattern in adult males. The number of midbody scales (58–62) in L. cinereus is higher than in L. chacoensis (42–48), but lower than in L. irregularis (60–74) and L. uspallatensis (60–76). From the latter, the new species further differs by having keeled dorsal scales (smooth or faintly keeled in L. uspallatensis ), less middorsal scales (67–71 versus 77–94), and underside of the tail inmaculate (spotted in L. uspallatensis ). Liolaemus cinereus further differs from L. montanezi (the only other species of the genus syntopic to it) in having different dorsal pattern and coloration, shorter tail, keel less marked on the dorsal scales, and lacking of antehumeral black pigment.

Description of the holotype. MLP.R 5139, adult male ( Figures 1–3 ), 59 mm snoutvent length; regenerated tail 77 mm long. Some scales on head, body and legs partial or completely black, irregularly scared and with texture change (evidence of disease?). Head 1.28 times longer than wide. Dorsal head scales smooth. Rostral 2.75 times wider than high, wider than mental, bordered behind by four postrostrals. Nasals anterodorsal in position, nearer to tip of snout than to eye; nostrils circular. Nasals medially separated by five irregular internasals and from the rostral by one postrostral each. Two postnasals on each side. Eight polygonal frontonasals. Two irregular prefrontals. All postrostrals, internasals, postnasals, prefrontals and frontonasals with several scattered brown scale organs. Two fused frontal azygous followed behind by three small frontoparietals. Interparietal pentagonal, with a conspicuous pineal eye. Six parietals; the four posterior to interparietal larger than the interparietal. Occipital scales polygonal and irregular, swollen, slightly rugose, subjuxtaposed; each one with 1–3 scale organs. Supraorbital semicircles with 12 / 13 polygonal scales. Ten supraoculars on each side, those medialmost transversely expanded, with 1–3 scale organs each. Supraoculars separated from superciliaries by one to three rows of small polygonal scales. Two canthals on each side, the anterior transversely expanded, the posterior 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 the fifth in the opposite direction. A single, short preocular followed by an elongate, concave and curved subocular several times longer than high, overlapped near its posterior end by a thin postocular, the three scales keeled all along. Palpebrals small, granular, juxtaposed. Ciliaries quadrangulars, projecting from the eyelid as a short “eyelash”. Loreals 6 / 4, in one or two rows, with several scale organs on each. Lorilabials 6 / 7, longer than high, the first three on each side higher than supralabials, the fourth subequal, and the remaining lower; all with several scattered scale organs. Seven supralabials, the fourth and fifth the longest, all longer than high. Temporals smooth, polygonal, convex, subimbricate; most with one, more rarely two, scale organs near their posterior or posteroventral border. Aperture of external auditory meatus suboval, higher than long, bordered anterior and posteriorly by small higher-than-long swollen scales, bearing one scale organ each; meatus bordered below by small ovoidal scales longer than high. Mental subpentagonal with concave lateral sides, 1.6 times wider than long, bordered laterally by the first infralabial on each side and posteriorly by two large postmentals. Six infralabials on each side, longer than high. 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 slight contact with the first infralabial, second pair separated from infralabials by one row of sublabials, the third and fourth pair by two rows, and the fifth and sixth by three rows of scales. Posterior gulars flat, imbricated, the posteriormost scales notched on the free margin.

Body slender. A skin fold out extended along both flanks, between fore and hindlimbs. Behind the tympanum a “ Y ” fold; one branch forward reaches posterodorsally the ear, other extends anteroventrally to the inferior border of the ear, and a third, the longest, runs longitudinally on the neck to fuse with the antehumeral fold. Scales of lateral neck region granular, juxtaposed, most of them with one scale pit each. Antehumeral fold distinct, lined by tiny granular scales. Dorsal scales on neck imbricated, smooth, a few blunt keeled. Scales on dorsolateral neck and body subimbricate, with one scale pit. Dorsal scales on body rhomboidal, imbricate, becoming subimbricate to dorsolateral; blunt keeled. Scales around midbody 62; middorsal scales 68. Dorsal body scales grade gradually to the sides into smaller scales juxtaposed, some faintly keeled but mostly smooth. Granular scales dorsally and posteriorly to forelimb insertion. Ventral body scales smooth, rhomboidal, larger than dorsals, imbricate. Ventral scales between postmentals and vent 89. Scales on precloacal region, between hindlimb insertions and vent, slightly larger than ventrals. Eight orange precloacal pores.

Dorsal scales on forelimbs faintly keeled, imbricate. Infrabrachial scales small, conical and juxtaposed. Infra-antibrachial scales larger, smooth, imbricate; progressively notched to become tridentate on wrist. Dorsal scales on manus large, rounded and notched, smooth, imbricate. Supradigitals smooth, wider than long. Palmar scales strongly keeled, mucronate, imbricate. Tricarinate, mucronate lamellae under digits; 22 under fourth left finger. Dorsal thigh scales faintly keeled and imbricate, become gradually smaller, smooth and juxtaposed to posterior. Patch distinct, formed by 38–40 scales larger than the neighbours, faintly keeled but erect and mucronate, subjuxtaposed. Thigh underside and infra-tibiofibular scales large, rounded and smooth, imbricate. Scales on dorsum of pes large, imbricate, smooth. Supradigitals smooth, longer than wide. Scales on sole of pes keeled, mucronate, imbricate. Tricarinate, slightly mucronate lamellae under digits; 30 under fourth left toe. Manus and pes with sharp, slender claws, equal in length to the span of 4–5 distal supradigital scales.

Tail 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. Ventral caudal scales smooth and imbricate proximally, gradually keeled and longer than wide to distal.

Coloration. In life, ground color of head, body and limbs ash-grey. Dorsal surfaces of body, limbs, and tail base with abundant white scales, single or in groups of 2–4 scales, forming rows more-or-less ordered. Grey nearly uniform in preservative. Brown paravertebral transverse bars, thin and broken, little evident. Middorsal and dorsolateral stripes absent as such or as lighter zones. Lateral surfaces of head with subsymmetrical pattern of dark brown lines, the foremost one runs longitudinally from the canthals to the anterior angle of eye; a second bar vertically crosses the middle of the eye from the superciliaries to the upper border of mouth; a third line runs longitudinally more-or-less continued through the temporals and neck from behind the eye, nearly reaching the prescapular spot. Supraciliaries, infraoculars, lorilabials and supralabials, whitish. Mental, infralabials, sublabials and postmentals whitish with occasional darker borders; definitely white in preservative. Extense dark brown pigment on the throat ( Figure 3 ).

“Pocket” formed by antehumeral fold lined in grey. Absence of bars related to the forelimb insertion as well as postscapular spots. The only evident spot is a rounded dark macula just dorsal to the antehumeral fold ( Figure 2 ), constant also in females (see below). On body flanks the ground color extends to the longitudinal fold, gradually fading to white from there. Irregular ink-black areas on head and body, probably reflecting an epithelial disease, obscure the pattern in this specimen.Ventral surface of throat, neck and anterior chest dark brown; gradually fading to immaculate white in venter, underside of forelimbs, hindlimbs and tail. Femoral patch scales white.

Variation. Based on the three female paratypes, the only other known specimens of Liolaemus cinereus . Snout-vent length 57 mm ( MLP.R 5140), 63 mm ( MACN 38798), and 62 mm ( MACN 38799); tail length (complete only in the MACN 38799) 83 mm. Scales around midbody 58–61 (mean 59.3 ± 1.53 SD); middorsal scales 67–71 (mean 69.7 ± 2.31 SD); ventral scales between postmentals and vent 98–100 (mean 99 ± 1 SD). Precloacal pores absent. Supralabials 7 (6 / 7 in MLP.R 5140); infralabials 6 (6 / 7 in MLP.R 5140). Infradigital lamellae under fourth left toe 30–31 (mean 30.7 ± 0.58 SD). Dorsal scales moderately keeled, but more evident than in male. Femoral patch less marked and less spinose than in male. Other lepidosis features (number of azygous frontals, form and arrangement of body scales, distribution of scale organs) as in the male, except for scales on precloacal region, which in females are rounded, nearly granular, juxtaposed and smaller than ventrals.

Coloration: Dorsal ground grey, with light brown shade. White scales less evident than in male to totally absent. Dorsal brown serial markings present as thin, discontinuous transverse bars, or as small squarish spots arranged in pairs at both sides of midline. On the tail dorsum these marks fuse on midline. Dark head lines as evident as in male, that one running from behind the eye easily visible from above. This line runs dorsolaterally on neck more-or-less continuously to end in a dark spot just dorsal to the antehumeral fold. Postscapular spot absent. Ill-defined brown stripes on the limbs, all scales finely dotted in brown. Black and white stripes on the posterodorsal surface of thighs. Femoral patch whitish. Throat white speckled with grey. Belly and other underparts, white ( Figure 3 ).

Etymology. The specific epithet is a Latin adjective meaning “ash-grey”, in reference to the overall background color characteristic in this species.

Geographic distribution. Liolaemus cinereus is known only from the type locality and the immediate vicinity of it. All specimens were found on gravel and sandy soil in a landscape of Monte vegetation associated to the higher portions of the banks of the Blanco River. The dominant vegetation are semi-arid scrubs of Larrea divaricata , Prosopis alpataco and Bulnesia retama , with high percentage of bare soil ( Figure 4 ). Other lizards syntopic with L. cinereus are L. montanezi (species of the same complex) and the Monte gekkonid lizard Homonota fasciata .

Natural history notes and Conclusions. The posterior marginal teeth (verified in the specimen MACN 38799) bear moderately cusped, slightly expanded crowns. An inspection into the large intestine of the same individual reveals undigested hard parts of insects and helminthic parasites.

The San Guillermo National Park ( Figure 5 ) is a protected natural area of Argentina covering 170000 hectares of High-Andean Puna landscape ( Chébez et al. 2005). The Park is the core section of the Biosphere Reserve of San Guillermo which, with its surface of 981000 hectares harbors the larger Argentinean populations of wild camelids (Vicugna vicugna and Lama guanicoe ), and gives protection to representative ecosystems and threatened fauna, e. g. the birds Fulica cornuta and Pterocnemia tarapacensis ( Haene et al. 2000) . Large plains between 3000 and 4200 meters of altitude surrounded by high cordilleras above the 4200 meters and deep ravines (“quebradas”) between 2100 and 3000 meters determine isolated spots that seem to have favoured speciation events. Most of the speciation processes in the darwinii complex may have happened during the Pleistocene and could be related to climatic changes during this period ( Morando et al. 2004). Hence the Reserve is, not unexpectedly, rich in iguanid endemisms: Phymaturus punae , Liolaemus eleodori ( Cei et al. 1983) , L. montanezi ( Cabrera and Monguillot 2006) , L. cinereus sp. nov., and several species under study and description by us and other researchers.

Figures

FIGURE 1. The holotype of Liolaemus cinereus, adult male, in life. The specimen is actually grey (see Figure 2); the brownish shade is an artifact due to lighting used to portray it.

FIGURE 2. The holotype of Liolaemus cinereus in life, showing the grey lining into the prehumeral fold (here extended) and the dark prescapular spot.

FIGURE 3. Comparative ventral view in life of the female paratype MLP. R 5140 (left) and the male holotype (right) of Liolaemus cinereus.

FIGURE 4. General view of the habitat of Liolaemus cinereus showing in the foreground bushes of Monte vegetation.

FIGURE 5. Map of the San Guillermo National Park (Landsat ETM image captured on 02 / 01 / 2002; Gauss-Kruger coordinates; Transverse Mercator Projection). A yellow circle marks the type locality of Liolaemus cinereus.