A new species of Phymaturus from rocky outcrops in the central steppe of Rio Negro province, Patagonia Argentina (Reptilia: Iguania: Liolaemidae) Author Scolaro, José Alejandro Author Ibargüengoytía, Nora Ruth text Zootaxa 2007 1524 47 55 journal article 10.5281/zenodo.273839 b3d5c820-70f6-4beb-8e90-48d3eb3567f0 1175-5326 273839 Phymaturus ceii n. sp. ( Figures 1 and 2 ) Type Material . Holotype : MLP-R 5289, adult male, collected in open rocky outcrops near Chasicó ( 40º 23' 02" S ; 69º 00' 33" W ; 1150 m asl), south of El Cuy Plateau, Rio Negro Province, Argentina . Collected by J.A. Scolaro and O .F. Tappari, 24 March 2006 . FIGURE 1. a. Adult male holotype of Phymaturus ceii in life from Chasicó, Río Negro, dorsal view. Photo: J.A. Scolaro, 24-03-2006. b. Adult male paratype of Phymaturus ceii in life from Chasicó, Río Negro, dorsal view, light greenish phase. Photo: J.A. Scolaro, 24-03-2006. FIGURE 2. a. Adult female paratype of Phymaturus ceii in life from Chasicó, Río Negro, dorsal view. Photo: J.A. Scolaro, 24-03-2006. b. Adults male and female: ventral view. Photo: J.A. Scolaro, 24-03-2006. Paratypes : MLP-R 5290, adult male; MLP-R 5291, adult female; MLP-R 5292, adult female; MLP-R 5293, adult male. All specimens have the same data of collection as the holotype . Etymology The species is dedicated to honour José Miguel Cei who reviewed this manuscript but died before its publication. He was internationally recognized and his work will remain indelible for future generations of herpetologists, because of his profuse and invaluable scientific contribution and proposal of new ideas for the biological sciences and evolution. Diagnosis Phymaturus ceii shows a noticeable sexual dichromatism. Males show a dorsal pattern of dark brown brick-like background, sometimes with light green shades intensely mottled with little white-grey spots. Females show a dorsal pattern of light brown background mottled with little grey spots and three strips, one vertebral and one on each side. These strips are conformed by dark brown scales of an intense variegated with numerous light brown spots separated by two strips of light brown scales. The coloration is dark brown, flecked with ocellus of irregular spots of a creamy colour, in different proportions on the limbs and an attenuated prominence of spiny scales on its caudal verticilles. It presents the Meckel’s groove fused, undivided subocular scale, thin and imbricate superciliaries scales and smooth dorsal scales on the tail. It shows two rows of lorilabials scales between the subocular and the supralabials. Description of the holotype A medium-sized lizard; snout-vent length SVL 85.8 mm ; tail length 104.6 mm (complete, not regenerated, 1.2 times of SVL); head length 17.7 mm ; head width 15.8 mm ; eye-nose distance 6.3 mm ; forelimb length 26.8 mm ; hind limb length 48.7 mm ; axilla-groin distance 43.2 mm (50.3% of SVL); fourth finger length 11.6 mm ; fourth toe length 14.4; scales in dorsal head 22; scales around midbody 234; ventral scales between mental and precloacal pores 178; supralabial scales 8-8; infralabial scales 7-8 decreasing posteriorly; subdigital lamellae on fourth finger 22; subdigital lamellae on fourth toe 28; precloacal pores 10; cephalic scales granular, almost smooth; supraorbital semicircles with large bulky scales, rounded, with an small azygous anteriorly, incomplete posteriorly on both sides; no distinct enlarged supraoculars; nine upper ciliaries; subocular elongate, slightly shorter than eye diameter, separated from supralabials by two rows of lorilabials; preocular separated from lorilabial row by two scales; temporals smooth irregularly quadrangular, in 7–8 rows from auditive opening to the subocular; external auditory meatus enlarged, transversal, with few enlarged (5–6) scales on its anterior border and diminute granular scales on posterior border; rostral more wide than high, separated by two small scales from nasals; nasal moderate, lateral, surrounded by 8 small scales; parietals irregular and rough with evident interparietal, surrounded by 8 scales; nuchals granular in few irregular rows; post–auricular folds evident with interposed transversal folds with round, almost granular, scales; undivided concave subocular; two lorilabial rows between subocular and supralabials; mental pentagonal smaller than rostral, surrounded by five irregular rectangular scales; two rows of 4–5 bilateral postmentals decreasing behind; dorsal scales small, round and juxtaposed; middorsal scales slightly enlarged decreasing smaller and granular toward ventro-laterals; ventrals slightly larger than dorsals, almost squared and smooth; gulars rounded and smaller; 75 gulars between auditory meatus; caudal scales quadrangular regularly imbricate in verticiles, proximally larger and smooth on dorsum, or softly keeled, distally more rectangular and keeled; scales in limbs round and slightly keeled in the upper side, granular and rounded in the lateral region, larger and flat in the lower side, infracarpals and infratarsals with round margins, becoming trifid to the base of fingers and toes. Subdigital lamellae of fingers keeled; claws moderately long. Coloration In life, the new species shows a notable sexual dichromatism. Males show a dorsal pattern of dark brown brick-like background, sometimes with light greenish tones intensely speckled with little whitegrey spots; its head is uniform in colour and its tail can present soft light brown and dark brown alternate rings ( Figure 1 a , b). Females show a dorsal pattern of light brown background speckled with little grey spots and three strips, one vertebral and one on each side, consisting of dark brown scales spattered with numerous variously light-brown spots. The dark strips are separated by two strips of light brown scales, which are sometimes irregularly broken. Its head is uniformly brown and its tail always presents rings forming two rows of scales, alternated with a soft light and dark brown colour ( Figure 2 a ). Ventrally, males show a pale reticulated dark grey on the throat over a light grey background; the neck upper part of the abdomen and front legs show a light grey colour; while the lower part of the abdomen and thighs vary in colour, from a pale yellow to a pale brick-like red. Females show a similar variegated coloration on throat and neck and a homogeneous pale grey on the ventral surface and legs ( Figure 2 b). Morphological variation The sample comprised 11 adult males and 14 adult females. Preliminary analyses allow us to establish sex differences being the females significantly larger in size than the males (SVL, P <0.01; axilla-groin distance, P <0.01). SVL 79.5–95.0 mm. Head length 15.0– 20.9 mm representing 0.18– 0.22% of SVL. Tail length 69.7–104.6 mm , 0.90–1.31 times SVL. Scales around midbody 232–245 (mean = 241.4; SD = 6.9). Dorsal head scales 19–23. Ventrals 175–190 (mean = 184.7; SD = 6.6). Precloacal pores only in males 6–15 (mean = 9; SD = 2.3). Scales surrounding interparietal 6–8 (mean = 7; SD = 0.8). Scales contacting mental 4–6 (mean = 5.1; SD = 0.8). Dorsal colour pattern is more variable between males than in females, from dark brown brick-like to light greenish tones background. Not all specimens shows strong ventral coloration (brick-like red), suggesting that this coloration may be related to season or physiological conditions. Other morphological measurements, means and ranges are shown in Table 1 . TABLE 1. Phymaturus ceii : means, standard deviations (SD) and ranges of the main morphometric characters. Measures in mm and scale numbers; ratios as proportions.

Variable	Males (N = 11)	Females (N = 14)	Comparison
Mean Range	Mean Range	Mean SD	P
Snout-vent length (SVL)	84.1 79.5– 89.9	88.0 82.2 – 95.0	86.3 3.76	<0.01
Tail length (TL)	92.2 69.7 – 104.6	93.7 86.5 – 99.9	94.6 5.23
Axilla-groin distance (AGD)	44.1 41.3 – 51.3	47.8 42.9 – 53.8	46.2 3.56	<0.01
Head length (HL)	17.3 15.0 – 20.9	17.4 16.5 – 18.6	17.4 1.08
Head width (HW)	15.9 15.5 – 16.7	15.6 14.8 – 16.4	15.8 0.49
Eye-nose distance (ED)	6.5 5.9 – 7.5	7.0 5.8 – 7.9	6.8 0.66
Forelimb length (FLL)	30.3 26.8 – 32.4	30.9 28.5 – 34.9	30.6 1.84
Hindlimb length (HLL)	47.5 41.8 – 50.6	46.6 43.1 – 50.8	46.9 2.34
Fourth finger length (FFL)	10.7 9.1 – 11.6	10.7 9.2 – 13.3	10.7 1.05
Fourth toe length (FTL)	14.2 13.4 – 15.5	14.1 11.3 – 18.8	14.1 1.36
Head dorsal scales (HDS)	20.6 19 – 22	20.9 19 – 23	20.8 1.13
Scales surrounding interparietal	7 6 – 8	7 6 – 8	7 0.8
Fourth toe subdigital lamellae	27.3 25 – 29	27.6 25 – 31	27.5 1.36
Fourth finger subdigital lamellae	22.9 22 – 24	22.2 21 – 24	22.5 1.08
Supralabial scale number	8.3 8 – 9	8.3 7 – 9	8.3 0.76
Infralabial scale number	8.2 7 – 9	7.7 7 – 9	7.9 0.76
Scales contacting mental	5.4 4 – 6	4.9 4 – 6	5.1 0.78
Precloacal pore number	9.2 6 – 15	– –	9 2.31
AGD/SVL ratio	1.11 1.04 – 1.22	1.09 1.00 – 1.16	1.10 0.05
TL/SVL ratio	1.12 1.04 – 1.22	1.09 1.01 – 1.16	1.10 0.05
HLL/AGD ratio	1.01 1.08 – 1.16	0.98 0.85 – 1.09	1.02 0.09
HLL/SVL ratio	0.56 0.52 – 0.62	0.53 0.48 – 0.59	0.54 0.03

Geographic distribution Phymaturus ceii was found on isolated volcanic outcrops of the type locality. More explorations in neighbouring areas are necessary in order to determine the whole species range. Natural history The Chasicó locality in Río Negro is a landscape formation of mountains, basaltic plateau and slope erosions. It shows altitudes around 1000–1200 m above sea level. Volcanic effusions and strong wind erosion have sculptured the present relief of this extended plateau. The region’s climate is characterized by prevalent cold aridity, 150–300 mm of annual rain, 8–10°C of mean temperature, with a strongly marked seasonal lack of humidity (in spring and summer), and intense winds from the west. Phymaturus ceii ’s biotope is found inside the arid district of the Monte Austral, a steppe showing open ground, with gravel and effusive rocks. The dominant landscape is the barren steppe, with shrubby, low herbaceous coverage, with bare soil percentages above 50%. The dominant vegetation is composed by cushion bushes and sparse large clumps, the Floristic Physiognomy Dominion are low shrubby steppes (with Nassauvia glomerulosa “colapiche”, N. axillaris “uña de gato”, Chuquiraga avellanedae “quilimbay”, Mulinum spinosum “neneo”, Senecio spp . “charcaos”, Stillingia patagonica, Acantholipia seriphioides “tomillo” and Grindelia chiloensis “melosa”), and mean shrubby-grass steppes (with Prosopis denudans “algarrobillo patagónico”, Prosopidastrum globosum “manca caballo” and Lycium spp . “yaoyín”, and bund grasses ( Stipa speciosa “coirón amargo”, Festuca pallescens “coirón dulce”and Stipa humilis “coirón llama”). On the basins, appears the halophilous shrubby steppe of Atriplex lampa “zampa” ( Cabrera 1971 ). The species inhabits a limited microhabitat and shares a general steppe habitat with other Iguanids Liolaemus ( L. elongatus , L. bibronii , L. boulengeri , L. rothi ), Diplolaemus sexcinctus and the gekkonid Homonota darwinii . However, because the new species tends to occupy only the rocky outcrops patches, few individuals of these other species share its microhabitat. The colubrid snakes Philodryas patagoniensis and Philodryas trilineata and the viperid Bothrops ammodytoides are common at the same locality, and may be its predators.