Phymaturus gynechlomus, Corbalan, Scolaro & Debandi, 2009

Corbalán, Valeria, Scolaro, Alejandro & Debandi, Guillermo, 2009, A new species of the genus Phymaturus of the flagellifer group from Central-Western Mendoza, Argentina (Reptilia: Iguania: Liolaemidae), Zootaxa 2021, pp. 42-56 : 48-53

Phymaturus gynechlomus sp. nov.

( Figure 4)

Type Material. Holotype: CH-IADIZA 330, adult male, collected in rocky slopes near Cruz de Piedra River , 2 km W of Alvarado Refuge of Laguna del Diamante Reserve, (2433 m of elevation), San Carlos Department , Mendoza province, Argentina. Collected by G. Debandi and V. Corbalán, 04 January 2006.

Paratypes: CH-IADIZA 331, adult female; CH-IADIZA 332, adult male; CH-IADIZA 333, adult female; MLP.R-5350, adult male; MLP. R.-5351, adult female. All specimens have the same collection data as the holotype .

Etymology. The species name derives from the peculiar dorsal coloration observed in females, in which the background is uniform and lacks any particular pattern of dark spots, as observed in other Phymaturus species.

Diagnosis. Phymaturus gynechlomus is a member of the flagellifer (= palluma ) species group because it exhibits juxtaposed superciliary scales, which are small with a quadrangular shape; fragmented subocular scales; well developed caudal spines and more than two rows of lorilabial scales between supralabial and subocular scales. The dorsal colour pattern of males of P. gynechlomus as well as the unique dorsal colour observed in females, which lacks dark spots, differentiate these species from the remaining members of the flagellifer group.

Description of the holotype. Adult male. Snout-vent length (SVL) 104.1 mm; head length 20.6 mm; head width 21.3 mm; head height 11.5 mm. Eye-nose distance 7.5 mm. Trunk width: 39.9 mm (38.29 % of SVL). Axilla-groin distance 43.5 mm. Twenty-one smooth dorsal head scales. Two to five scale organs on postrostrals. Subocular scales divided into five parts (5/5). Three rows of lorilabials between suboculars and supralabials. Four internasal scales. Nasals bordered by nine irregular scales of different size, not in contact with rostral, separated by three irregular scales of different size. Canthal separated from nasal by three scales. Loreal region flat. Supralabials 9/10; infralabials 9/10. Auditory meatus oval-sigmoideus, three/four notorious, triangular and sharp-pointed, lighter scales on anterior margin of auditory meatus. Eight rows of temporal scales, juxtaposed and wrinkled. Rostral scale undivided, wider than higher. Mental less wide but higher than rostral, subpentagonal in contact with six scales. Interparietal subpentagonal bordered by six small irregular parietal scales of different size. Frontal region without an azygous scale. Supraorbital semicircles are posteriorly incomplete on both sides. No distinctly enlarged supraoculars. Superciliars 9/10 clearly distinguishable. Sixteen lorilabials (first row at right side), the two latest in contact with subocular scales. Three scales between preocular and lorilabial row. Postmentals in two rows of three bilateral enlarged and subpentagonal scales decreasing in size behind. Gular scales round, small, flat and juxtaposed. Hemigular groove present. Two notorious gular folds; the first fold with posterior scales, which are subpentagonal, greater, smooth and juxtaposed. Second fold incomplete. Fifty-eight gular scales before the first fold. Nuchal folds notorious with granular scales, smaller than dorsals. Antehumeral tuft well developed. Number of ventral scales between mental and precloacal pores: 180. Scales around midbody: 228. Ten precloacal pores and two very small supernumerary pores. Dorsal round scales subhexagonals, smooth, juxtaposed, each one bordered by 6 or 7 small scales. Forty-six dorsal scales along midline of the trunk in a distance equivalent to head length. Mid-dorsal scales enlarged in comparison to those on flanks. Ventral scales larger than dorsals. Brachial and antebrachial scales smooth with rounded posterior margins. Supracarpals round and smooth. Subdigital lamellae of finger IV: 19/20 (anterior) with 3 to 5 keels, 24/24 (posterior) with 3 or 4 keels. Claws well developed, prominent and curved. Supradigital lamellae convex, smooth, round and imbricated. Infracarpals and infratarsals with round margins. Infracarpals bi- or tri- keeled. Infratarsals keeled. Supracarpals and supratarsals smooth, with round margins, slightly keeled, more conspicuous in lateral margins. Caudal scales regularly verticillate, lateral and dorsally squared and with spines very well developed. Twenty-three scales by verticilles in the middle of the tail. Medial ventral furrow in the tail, with 2 or 3 scales slightly mucronated.

Coloration. In life, the new species shows conspicuous sexual dichromatism. Males exhibit a black head splashed with small irregular gray spots ( Fig. 4). Black scales are very intense on lateral nuchal folds, lacking a small vertebral stripe of cream to greenish scales from the first nuchal scales to an early portion of the tail. The black coloration is more intense towards the shoulders. Lateral folds show irregular spots of intense light green colour. Dorsum and dorsal scales side of forelimbs show a brilliant light green background with yellow shades, with a marbled pattern of small, irregular black spots. The flanks, from the axillary to inguinal region are light green with scattered sky blue scales, without any black spots or grooves. The tail is intensely orange dorsally, and pale ventrally. From the ventral view, throat and chest are intensely black, shading towards the first portion of the flanks. The ventral surface is of intense yellow speckled with faint blackish spots on the flanks, which shade towards the cloacal region and ventral surface of limbs to pale yellow-greenish with lightblue scales. Precloacal pores are reddish to intense orange.

Interindividual variation. As previously stated, there is evident sexual dichromatism in this species ( Fig. 4). Females show a dorsal head and dorsal light brown forelimbs with small irregular gray spots; without black grooves or spots. Temporal region is lighter than the rest of the head. Dorsally, they show vertebral light gray greenish scales almost in continuous line from the first nuchal scales to the first portion of the tail; the background changing from light brown to dark green, without any spotted pattern, stripes, ocelles or grooves. Some specimens show tenuous brown spots that are light, irregular and laterally more conspicuous. The inguinal region shows greenish or bluish tonalities. The tail is brown, with some specimens showing transversal pale light and dark bands. Ventrally, intense marbled gray and black, never melanic. Abdomen of intense gray, slightly spattered with dark small spots. The chest is slightly yellowish ( Fig. 4). Some individuals show blue scales. Flanks are gray greenish with intense spattering of black spots. Precloacal pores are present only in males (8–10 with 1–2 supernumerarious pores). The statistical comparison between adult individuals showed that males have wider heads, longer heads, longer eye-nose distance and higher HLL/SVL ratio than females ( Table 3). No significant differences were found for any discrete variables.

Adpressed hindlimb never reaches the shoulder either in males or females. Length of entire tail is 100.59% of snout-vent length in females (range = 98.73–103.64%) but it is 98.96% in the only male measured. Tail measurement is often impossible given the elevated number of broken or regenerated tails in the sample analyzed. Variations for some other metric and meristic characters are shown in Table 3.

Geographic distribution. Phymaturus gynechlomus was found only in isolated slopes of the type locality. This species was observed between 2400 and 2960 m of elevation. According to the potential distribution based on predictive models it is possible that the distribution of this species is greater, reaching Uspallata to the North and Payunia to the South. More explorations in neighbouring areas are necessary in order to validate the predictive models and to determine the whole species range.

Natural history. As the other species of the genus, P. gynechlomus inhabits rocky slopes, where they find refuge against predators and adverse climate conditions. The rocks of the area have volcanic origin. A photograph of the habitat of P. gynechlomus is shown in Fig. 5. Most lizards were found basking on the rocks, while some female specimens were observed near the Cruz de Piedra stream.

On the collecting day (January 4, 2006), we observed that the individuals of P. gynechlomus began the activity at 10 hrs, when air temperature was 25.5 º C, temperature at 2 cm above ground was 28.8 ºC, and temperature of rocks was 27.7 ºC. The mean cloacal temperature of 5 individuals (3 males and 2 females) captured between 10:00 hrs and 11:45 hrs was 33.5 º C, whereas the mean temperature at 2 cm above ground during the same period of time was 29.7º C. Reaching midday, many individuals were also basking. The activity of the lizards finished at about of 19:00 hrs .

The vegetation of the area is mainly composed by Grindelia chiloensis , Senecio subulatus , Senecio aff. filaginoides var. lobatus (Asteraceae) , Junellia spathulata var. glauca (Verbenaceae) , Poa aff. resinulosa , Elymus erianthus (Poaceae) , Mulinum spinosum (Apiaceae) and Adesmia aff. aegiceras (Fabaceae) . These species were identified by botanists of IADIZA-CONICET, from samples collected on the site and date of capture.

Other lizard species observed in sympatry with P. gynechlomus were Liolaemus austromendocinus Cei and L. elongatus Koslowsky.