Liolaemus uptoni, Scolaro, José Alejandro & Cei, José Miguel, 2006

Scolaro, José Alejandro & Cei, José Miguel, 2006, A new species of Liolaemus from central steppes of Chubut, Patagonia Argentina (Reptilia: Iguania: Iguanidae), Zootaxa 1133, pp. 61-68 : 62-65

Liolaemus uptoni sp. nov.

( Figure 1a .)

Type Material — Holotype: MACN­38742, adult male, collected in open steppe zone with abundance of sandy eolic deposits; Bajada del Buey (42º23'46" S; 68º57'56" W; 815 m asl), west of Pampa de Sacanana, Provincial Road 4, Km 360, Chubut Province, Argentina. Collected by J.A. Scolaro and J.A. Upton, 10 April 1997.

Paratypes: MACN­38743, adult male; MACN­38744, adult female, MACN­38745, adult female. All specimens same data of collection as the holotype.

Etymology —The species is dedicated in homage to the memory of our late friend and collaborator, Jorge Arturo Upton, who together the authors explored vast areas of Patagonia for almost 30 years.

Diagnosis — Liolaemus uptoni differs from other Liolaemus species for its coloration and lepidosis, being close to Liolaemus somuncurae belonging to kingii group. Its lepidosis shows a dorsal pattern of paravertebral lighter scales, notoriously keeled and larger than in L. somuncurae . The black parietal pileus is more accentuated. Ventral melanism is moderate, with a reticulate pattern of spots and pigment blots more expanded and confluent on a medial line, and semicircular black bands over the cloacal region. Hindlimbs are long, reaching the antehumeral region in females but exceeding it in males: a character which does not occur in L. somuncurae .

Description of the holotype —A median­sized lizard; snout­vent 86.5 mm; head length 20.0 mm; head width 18.0 mm; forelimb length 26.5 mm; hind limb length 44.0 mm; axilla­groin distance 37.0 mm; scales around midbody 78; supralabial scales 8–9; infralabial scales 7–8 decreasing posteriorly; subdigital lamellae on fourth toe 27; subdigital lamellae on fourth finger 23; precloacal pores 8; cephalic scales irregular and bulky, almost smooth; supraorbital semicircles with large bulky scales, rounded, with an azygous anteriorly; three enlarged and three smaller supraoculars which are separated from semicircles by a regular row of diminute rounded scales and from narrow and keeled superciliaries by two short rows of median­sized irregular scales; temporals smooth irregularly quadrangular, in 8 rows from auditive opening to the subocular; external auditory meatus enlarged, transversal, with few rounded scales on its anterior border and diminute granular scales on posterior border; rostral more wide than high, separated by two small scales from the moderate, lateral nasals; parietals irregular and rough with evident interparietal; nuchals granular in few irregular rows; post­auricular folds evident with interposed transversal folds; undivided subocular concave; a lorilabial row between subocular and supralabials; mental equal to rostral, surrounded by four irregular rectangular scales; four bilateral postmentals decreasing behind; dorsal scales small, imbricate, keeled, decreasing toward ventro­laterals, larger and smooth; ventrals the same size of dorsals, rounded and smooth; gulars rounded and smaller; caudals proximally larger and smooth on dorsum, or softly keeled, distally more rectangular and keeled; round and flat scales in limbs, larger in the upper side, granular and rounded in the lateral region, flat in the lower side, diminute and granular inside thigh and axillae, also in plantar surfaces.

Coloration — In life, dark brownish dorsal coloration, with darker cephalic region, and black evident pileus in parietal region ( Fig. 1 , a); pale vertebral­paravertebral band of 5–6 rows of yellowish scales, from nuchal region to proximal tail region, where it narrows. Ventrally, dense dark reticulations at the gular region, on white yellowish background; laterals and limbs with a peculiar light green pigmentation, and 8 orange pre­cloacal pores.

Morphological variation —The sample was scarce: three males (one of them subadult) and two adult females. Preliminary analysis does not allow to establish any sex difference in size or in any other morphometric measurement.

The sample scarcity prevented us to carry out statistical tests for the identification of significant differences in analysed variables. Although some tendencies have been observed in a preliminary way, these should be analysed in the future with an increased number of individuals. Generally, larger hind limbs than in L.somuncurae were observed; when extended they exceed axilla­groin distance, being always larger in the males.

Geographic distribution — Liolaemus uptoni was found under isolated bushes present on sandy grounds and eroded slopes at Bajada del Buey, and west of Pampa de Sacanana, Chubut. More explorations in neighbouring areas are necessary in the future to determine the whole species range.

Natural history —The Pampa de Sacanana in Chubut is a landscape formation of flat sedimentary basins and wind eroded strips surrounded by the mountainous system of Talagapa­Catandil­Toronqueñeu and the Meseta de Somuncurá northwards and westwards, by the plateau and Sierra Negra of Telsen Eastwards, and the Chacay mountains south­eastwards. It shows altitudes around 600–800m above sea level. Volcanic effusions and strong wind erosion have sculpted the present relief of this extended plateau. Several close basins, formed by slope erosions of its peripheral relief, provide temporary clay lagoons, which promote present sandy accumulations of eroded ground and remarkable mounds around its few bushes.

The weather of the region is characterized by prevalent aridity, with a strongly marked seasonal lack of humidity. L. uptoni s biotope is found inside the central district of the Patagonian steppe, showing open ground, with gravel and effusive rocks. The dominant physiognomy is the barren steppe, with shrubby, herbaceous low coverage, with bare soil percentages above 50%. The dominant vegetation is composed by cushion bushes of Mulinun spinosum, Nardophyllum chiliotrichioides, Nassauvia ulicina, N. glomerulosa, Brachyclados caespitosus, Azorella monanthos, Junellia mulinoides, Acantholippia seriphioides, Ephedra ochreata, Senecio filaginoides, Tetralochin caespitosum; sparse large clumps of Lycium chilense, Schinus polygamus, Adesmia volckmanni, and bunch grasses of Stipa humilis , S. neaei , S. speciosa and Hordeum comosum .

Liolaemus uptoni inhabits a limited microhabitat, given by the root system, in the fine sandy mounds under the bushes. They are wary and when the intruder is still at a considerable distance, they run quickly across patches of bare soil, seeking shelter under the bushes, and they bury readily in sand. Although rocky outcrops are very near, none was found having neither basking nor turning over rocks. The species shares a general steppe habitat with other Liolaemus ( L. elongatus , L. bibronii , L. boulengeri , L. rothi ), Diplolaemus darwinii , D. sexcinctus and Homonota darwinii . However, because the new species tends to occupy the more sandy patches, few individuals of these other species share its microhabitat. The snakes Philodryas patagoniensis , P. trilineata and the viperid Bothrops ammodytoides are common at same locality, and may be its predators.

Figures

FIGURE 1. a. Adult male holotype of Liolaemus uptoni in life from Bajada del Buey, Gastre, Chubut, dorsal view. Photo: J. A. Scolaro, 07 ­ 03 ­ 2000. b. Adult male holotype of Liolaemus somuncurae from a landscape between Laguna Raimundo and Laguna Miñuelo, 1400 m asl., Somuncurá Plateau, Río Negro. Photo: J. M. Cei, 21 ­ 02 ­ 1980.