Liolaemus galactostictos, Avila & Vrdoljak & Medina & Massini & Perez & Sites Jr & Morando, 2021

Avila, Luciano Javier, Vrdoljak, Juan Esteban, Medina, Cintia Débora, Massini, Juan García, Perez, Cristian Hernán Fulvio, Sites Jr, Jack W. & Morando, Mariana, 2021, A new species of Liolaemus (Reptilia: Squamata) of the Liolaemus capillitas clade (Squamata, Liolaemini, Liolaemus elongatus-kriegi group) from Sierra de Velasco La Rioja Province, Argentina, Zootaxa 4903 (2), pp. 194-216 : 199-211

Liolaemus galactostictos sp. nov.

Holotype. LJAMM-CNP 18124 ( Fig. 4 ), an adult male from Pampa de Vinigeao , El Cienagondo , in front of Estancia Vinigeao , San Blas de los Sauces department, La Rioja province, Argentina (28º45’53,53”S, 67º08’00,94”W, 3427 m), collected by A. Leaché, 2 February 2018.

Paratypes. MLP-S 2639 (ex-LJAMM CNP 18114), 2642 (ex-LJAMM CNP 18126), 2643 (ex-LJAMM CNP 18128), LJAMM CNP 18125/7 18128 (males, Fig. 5 ) and LJAMM CNP 18115–18121 , MLP. S 2640 /2641 (ex- LJAMM CNP 18122/18123) (females, Figs. 6 , 7 ) from same locality as holotype. collected by same collector, 2 February 2018 .

Diagnosis. A moderate to large-bodied, elongate lizard belonging to the Liolaemus capillitas clade, that can be distinguished from all other members of that group (and all other Liolaemus ) by having homogeneous black bodied coloration on dorsal and lateral sides of head, body, tail and limbs, with a well-marked white vertebral but irregular band between occiput to rump ( Figures 4 and 6 ) and lack of white spotted shoulders. Liolaemus galactostictos sp. nov. differs from L. capillitas , L. dicktracyi , L. heliodermis , L. talampaya and L. umbrifer in having a shorter snoutvent length (max SVL 81.3 mm vs 93.1, 91.0, 91.4, 88.1 and 88.4 mm) but is slightly larger than L. tulkas (max SVL 76.8 mm). Liolaemus galactostictos sp. nov. also differs from L. capillitas by having higher average number of midbody scales (66.0 vs 62.0), dorsal scales (75.6 vs 64.8) and ventral scales (105.1 vs 99.9). Liolaemus galactostictos sp. nov. differs from L. dicktracyi in having more dorsal scales (average 75.6 vs 68.2) and lacks any indigo/light blue coloration. Liolaemus galactostictos has more and not-overlapping dorsal scales than L. heliodermis (70–79 vs 62–65) but less, and not-overlapping ventral scales (102–108 vs 109–116) and lacks any sulphur-yellow coloration in its body. Liolaemus galactostictos sp. nov. has more and not overlapping dorsal scales than L. talampaya (70–79 vs 64–69), has fewer number of precloacal pores (1–2 vs 3–5), and lacks any tan/light brown body coloration. Liolaemus galactostictos sp. nov. differs from L. tulkas in having a smaller average number of dorsal scales (66.0 vs 71.6) but higher number of ventral scales (75.6 vs 71.8).

Description of holotype. Adult male ( Fig. 4 ). SVL 81.3 mm, total length 178.9 mm; tail complete, regenerated (97.6 mm length). Axilla–groin distance 39.8 mm. Head 17.9 mm long (from anterior border of auditory meatus to tip of snout), 15.5 mm wide (at anterior border of auditory meatus), 9.8 mm high. Arm length 22.6 mm. Tibia length 16.3 mm. Foot length 22.3 mm (ankle to tip on fourth toe).

Dorsal head scales irregular, smooth, bulged, 15 between rostral and occiput (at level of anterior border of auditory meatus). Rostral scale wider (3.70 mm) than high (1.29 mm). Two postrostrals, fragmented, two supernumeraries, four internasals, four frontonasals. Five prefrontals, irregular, arranged two-two, with a smaller rhomboidal scale in the between. Frontal scale complete, forming one scale rows between circumorbitals. Six scales between frontal and rostral. Interparietal pentagonal, smaller than parietals. Interparietal white surrounded by five scales, with a central, small, and barely visible ‘‘parietal eye’’ in center of scale. Supraorbital semicircles complete. Six enlarged supraoculars (both sides).

Four scales between frontal and superciliaries. Seven superciliaries, irregular flattened and elongated. Twen-ty–seven temporals on each side, smooth and protruding with 0–3 scales organs. Scale organs more abundant in the anterior head region than in the parietal and temporal region which have become scarce.

Canthal scales separated from nasal by one scale. Loreal region flat. Seven scales surrounding nasals on each side. Nasal in contact with rostral on each side. Orbit with 15 upper and 13-12 lower ciliaries. Orbit diameter 2.7 x 5.6 mm. Subocular scale elongate. One preocular, quadrangular. Seven lorilabials, four in contact with subocular. Six supralabials on each side. Fourth supralabial (5 on right side, fragmented) curved upward posteriorly. Infralabials five, first scale equal as posterior infralabials. Loreal, lorilabials, supralabials, infralabials, nasals, internasals, frontonasals, and prefrontals with conspicuous scale organs, postrostrals injured.

Three outwardly projecting scales along anterior border of auditory meatus. Auditory meatus twice as high (3.6 mm) as wide (1.8 mm). Lateral scales of neck granular with skin below appearing slightly inflated. Antehumeral, longitudinal, postauricular, rictal and oblique neck folds distinct, gular incomplete. Twenty–four scales between auditory meatus and antehumeral fold (counted along longitudinal fold). Scales of dorsal neck region similar to dorsals.

Mental wider (3.5 mm) than high (2.0 mm), followed posteriorly by two rows of 3/3 chinshields. Chinshields no in contact with mental, separated by two postmentals. Throat scales between chinshields slightly juxtaposed, strongly imbricate toward auditory meatus. Fourty–two gulars between auditory meatus.

Seventy–five dorsal scales between occiput and anterior surface of thighs. Dorsal body scales with round posterior margin, slightly imbricated, keeled to weakly keeled. Forty longitudinal keeled scales rows. Scales become increase size and less keeled through flanks. Flank scales with one scale organ at the tip. Scales small and granular around limb insertions. Sixty-eight scales around midbody. Ventral scales of similar size to dorsal, but smooth and round, 104 scales between mental and cloacal aperture. Precloacal scales equal than ventral. Two precloacal pores, each with an orange waxy exudate.

Tail quadrangular in cross section near cloacal area, becoming oval to round in the rest. Caudal scales in discern-ible annuli. Dorsal and upper lateral caudal scales keeled, imbricate, 1–6-mucronate (always one more developed than the other), and not outward projecting. Lower lateral scales moderately keeled and mucronated, and ventral scales smooth. Caudal scales of the regenerated portion smaller, keeled, imbricate, and mucronate.

Suprabrachials imbricated, weakly keeled and prebrachials smaller, smooth, and imbricate. Infrabrachials small-er and granular. Supra–antebrachials imbricate, smooth, some very weakly keeled; post–antebrachials imbricate, moderately keeled; pre–antebrachials imbricate, smooth; and infra–antebrachials imbricate, becoming of smooth in the posterior region to moderately keeled and 1–5-mucronate at the anterior region. Suprametacarpals imbricate, smooth; inframetacarpals imbricate, and keeled. Supradigitals of manus smooth, wider than long; subdigitals with three keels, each terminating in a short blunt mucron, numbering: I: 9, II: 13; III: 19; IV: 18; V: 15. Claws robust, moderately curved, opaque black.

Suprafemorals imbricate, moderately keeled; prefemorals and infrafemorals imbricate, smooth. Postfemorals small, granular. Supra– and pretibials imbricate, moderately blunty keeled; infratibials imbricate, smooth. Supratarsals imbricate moderately keeled and smooth toward anterior region; and infratarsals imbricate, keeled, 1–4 mucronate. Supradigitals scales of foot, rhomboidals, imbricated in two rows, one lateral rows smooth and one dorsal rows weakly keeled. Subdigital scales 4–5 keeled, mucronate, numbering: I: 11; II: 16; III: 21; IV: 24; V: 17. Claws robust, moderately curved, opaque black.

Color of holotype in life. Dorsal and lateral head, body, limb and tail, black in all of its surface. Middle dorsal region with a white wedge-shaped line, with the widest part in the nuchal region (six scales wide) and the sharper (one scale wide) in the anterior surface of thighs. Dorsal head with some white irregular spots on left side scales.

Ventral surface of mental region, neck and ventro-lateral region of the throat, chest, belly and forelimbs black; ventral surface of the chest, lower belly and cloacal apron dark gray; infratibial and infratarsal region, ventral scales of the digits and upper belly white; Infracarpal and infrafemoral region, and ventral scales of the digits red. Ventral surface of tail black.

Color of holotype in preservative. After three years in preservative, the dorsal coloration of the head, dorsum, body flanks and tail lose brightness but still is strongly melanic. Ventral surface of the throat, chest and upper belly light gray; lower belly, ventral surface of the forelimbs, cloacal apron and upper tail region (around cloacal apron) became clear.

Variation. Based on the type and paratype series of five males and nine females ( Table 7 ). As in other members of the Liolaemus elongatus-kriegi group, no remarkable body size dimorphism or sexual dichromatism is observed as in other groups of Liolaemus (except base tail expansion in males and lack of precloacal pores in females). In six males ( Table 7 ): SVL: 54.6–81.3 mm. Axilla–groin distance: 26.1–39.8 mm. Head length: 12.1–17.9 mm. Head width: 9.8–15.5 mm. Head high: 6.3–9.8 mm. Foot length: 18.9–23.2 mm. Tibial length: 12.0– 16.5 mm. Arm length: 16.8–23.7 mm. Midbody scales: 64–69. Dorsal scales (between occiput at the anterior margin of auditory meatus and anterior surface of thighs): 70–79. Ventral scales 102–108. Fourth toe lamellae: 24–27. Third toe lamellae: 18– 20. Supralabial scales: 6. Infralabial scales: 4–5. Cloacal pores: 1–2. In nine females ( Table 7 ): SVL: 61.3–76.3 mm. Axilla–groin distance: 27.3–39.7 mm. Head length: 13.0–16.0 mm. Head width: 11.2–13.4 mm. Head high: 6.9–8.4 mm. Foot length: 19.5–21.0 mm. Tibial length: 12.5–14.5 mm. Arm length: 19.1–21.0 mm. Midbody scales: 64–67. Dorsal scales: 73–79. Ventral scales: 104–108. Fourth toe lamellae: 24–29. Third toe lamellae: 17–20. Supralabial scales: 6–7. Infralabial scales: 4–6.

All males and females exhibit a black coloration in upper and lateral sides of the head, trunk, limbs and tail when they were observed and chased. Usually this coloration fade after capture and some areas becomes ochre to dark brown, usually dorsolateral areas of the trunk.

Conspicuous white band is variable in females, from a well-marked irregular band in adults from the neck to the base of the tail, but in smaller animals band is reduced to a separated white dots sometimes reduced to a small area between neck and midbody ( Fig. 7 ). In larger animals, some irregular in size and shape white dots are irregularly dispersed in the head and first two thirds of the tail, but in small animals they are not present. Dorsal and lateral coloration in life is almost identical in all individuals and varies only in intensity. Yellow ventral coloration of males in femoral, cloacal central region and lower belly region is variable in extent and intensity in the indicated areas. In preservative, dorsal coloration of all individuals fades to a darker color, although all retained the contrast between back and head and flanks and scattered white spots never disappeared. All distinctive femoral areas and lower belly coloration fades in preservative from yellow to dark gray.

Adult females LJAMM-CNP 18115/6 had crimson red coloration in the cloacal apron and lower belly region and at the base of the thighs and tail when collected, otherwise sexual dichromatism is absent. All other females’ lizards, smaller in size, lack of any coloration in this body region.

Etymology. The specific epithet galactostictos is derived from the combination of the greek words galacto (milk) and stiktos (spotted or dappled), in reference to the evident white mark along the vertebral region on the body.

Distribution. Liolaemus galactostictos sp. nov. is known only from the type locality ( Figs. 8 , 9 ), from Pampa de Vinigeao, El Cienagondo, in front of Estancia Vinigeao, San Blas de los Sauces Department, La Rioja Province, Argentina (28º45’53,53”S, 67º08’00,94”W, 3427 m).

Natural history and habitat. Little information about natural history and biology of this new species is available. Lizards were observed basking on rocks in around one hour of field work by hand or nooze. We were unable to determine the reproductive mode of Liolaemus galactostictos sp. nov. but as it lives at high elevations (over 3400 m) and because its closest relatives are viviparous, we expect that this species is also live bearing. Feces produced by Liolaemus galactostictos sp. nov. (n = 15) within 4 days of capture contained the remains of Insecta and partially digested plant parts.

The Sierra de Velasco is a large mountain range in the northeast of La Rioja with heights that reach up to four thousand three hundred meters. This is part of the Extrandean Pampean Sierras and its rocks, of igneous and metamorphic origin, have ages that go back to the Ordovician and Carboniferous period, in the lower to middle Paleozoic, three to four hundred million years ago ( Ramos 1999; de los Hoyos et al., 2011). The extensive altitudinal development and the latitudinal variation of the Sierra reflect the complexity of a topography that, added to the influence of a subtropical climate from warm to cold and dry, seasonally and locally variable, and a dynamic geological history, have amalgamated into a relatively small area an incredible variety of habitats that are part of ecosystems that vary from those strictly terrestrial to other continental freshwater (e.g, high altitude wetlands, bogs or vegas sensu Cabrera & Willink 1980). Up to four ecological regions can be distinguished based on different characteristics, including elevation, topography and plant and animal distribution ( Cabrera 1971, 1976; Cabrera & Willink 1980; Burkart et al. 1999; Morello et al. 2012). The newly discovered lizards inhabit the most elevated areas of the sierra (above ~3000 mts high), which correspond to the Prepuna-Puna ecotone and the Puna ecological region ( Cabrera 1971; Morello et al. 2012). This is because the latter ecological region has not been defined specifically for the Sierra de Velasco, but, which, however, shows features, named plants, animals and overall topographic characteristics and elevation that are also found in the Prepuna and Puna, elsewhere to the north of La Rioja province. The Puna in the Sierra de Velasco is characterized by north-south facing sierra slopes capped by extensive high altitude rolling plains (from ~3200 to 3800 mts high), interrupted by rocky outcrops reaching ~4200 mts in elevation, and, deep east-facing cuts into the terrain, with numerous natural springs that develop into creeks of variable size. Several of the same plants present in the Prepuna also extend all the way up into the highlands of the sierra to elevations that correspond to the Puna. Especially abundant along the grassy slopes that enter into the Puna are some Cactaceae of cushion-like and short columnar habits, including Maihueniopsis boliviana and Lobivia sp., Denmozoa sp., Gymnocalycium sp. and Trichocereus sp., which are well adapted to the dry and cold seasonal climate. The highland plains are exposed to recurrent strong winds from all directions, especially southern and northern winds, and are characterized by a low shrub steppe and pastures of grasses of Stipa , Festuca and Poa genera ( Poaceae ), locally known as Aive and Coiron, which appear as grouped or dispersed clumps with bare soil spaces between them; this is a shared feature with plains in the Puna in northernmost provinces of Argentina ( Reboratti 2006) where other members of the capillitas clade inhabit. Other plants, typical of the site are chachacoma ( Senecio graveolens /eriophyton), marancel ( Perezia sp.), escorzonera ( Perezia sp.), muña -muña ( Micromeria eugeniode s), añagua ( Adesmia sp.), Ranunculus sp., nencia ( Gentianella sp.), Hieronymiella , Sisyrinchium sp., yareta ( Azorella compacta ), Parastrephia sp., among others ( Cabrera 1976; Reboratti 2006). The newly discovered lizards were observed from 3000 to 3700 meters high in the northernmost portion (along a transect of ~ 15 km long of the ~ 150 km extension of the sierra, ~ 15 km from the norther tip) of the Sierra de Velasco. Inhabiting north and sometimes east facing rocky outcrops isolated in the middle of grassy plains, the lizards used cracks for shelter, coming out around noon to bask on their respective mother rocks. Living in or around those same rocks are ferns ( Anemiaceae ) and common vascular plants, such as muña-muña ( Lamiaceae ) and zapatito ( Calceolariaceae ) were observed. Only Phymaturus mallimaccii and Pleurodema spp. were observed in the area.

Figures

FIGURE 4. Liolaemus galactostictos sp. nov., paratype adult male, dorsal and ventral views.

FIGURE 5. Liolaemus galactostictos sp. nov., paratype adult males, dorsal and ventral views.

FIGURE 6. Liolaemus galactostictos sp. nov., paratype adult female, dorsal and ventral views.

FIGURE 7. Liolaemus galactostictos sp. nov., paratype adult females, dorsal and ventral views.

FIGURE 8. Type locality of L. galactostictos sp. nov. at 4327 m. in Sierra de Velasco, La Rioja province, Argentina. Upper: general view of the area. Below: microhabitat close view at collection site.

FIGURE 9. Map of Sierra de Velasco and main orographic landmarks in northern La Rioja and southern Catamarca provinces, with type localities of phylogenetically related species of the capillitas group. Liolaemus galactostictos sp. nov. (red star) type locality. Liolaemus tulkas, inferred as the sister species (red square), L. talampaya (black star), L. dicktracyi (white stars), L. capillitas (red circle), L. umbrifer (blue squares), L. heliodermis (green circle). Smaller black dots: main cities in the area. Small rectangle in the inset mark the region in South America.