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We describe Liolaemus attenboroughi sp. nov., a lizard distributed in the northwestern Patagonian Steppe of Chubut province (Argentina) previously confused with L. kingii (Bell 1843). Recent studies based on molecular evidence supports its evolutionary independence. Here we provide a morphological diagnosis of this lineage, comparisons between three molecular species delimitation methods, and an updated phylogeny of the L. kingii group. Based on current knowledge of its distribution, this new species is allopatric with geographically close species of the L. kingii group.

Liolaemus attenboroughi, new species 1975 Liolaemus kingi Cei, 1975 Herpetologica 31(1): 109–116. 1986 Liolaemus kingi Cei, 1986 Museo Regionale di Science Naturali Torino, Monografie 4: 1–527. 2015 Liolaemus kingii Minoli et al., 2015 Zookeys 498: 103–126. Holotype. LJAMM-CNP 16782 (Fig. 4): Adult male. Locality: National Road 40, 39 km N of Gobernador Costa, between Putrachoique and La Paulina ranch, eastern slope of Cordón de Putrachoique, Tehuelches Department, Chubut Province, Argentina (43°51′22.5″S, 70°54′57.4″W, 859 m.a.s.l.). Collector: L.J.Avila.Date: January 30,2018. Paratypes. See Figures 5, 6, and 7. LJAMM-CNP 16781, 16784, MLP. R 6828 (ex LJAMM-CNP 16783) (adult males), and LJAMM-CNP 16786 (adult female), same data as holotype; LJAMM-CNP 3678 (adult male) and 3679 (adult female) from Provincial Road 12, La Cancha pier, Cushamen Department, Chubut Province, Argentina (42°47′47.3″S, 70°57′30.2″W, 762 m.a.s.l.), collected by N. Frutos, C.H.F. Perez, M. Morando, P. Frutos, L.J. Avila, and T. Avila (February 8, 2006); LJAMM-CNP 3680, 3702 (adult females), and 3701 (adult male) from Provincial Road 17, 52.5 km SE Corcovado, Languiñeo Department, Chubut Province, Argentina (43°37′42.5″S, 70°59′49.8″W, 770 m.a.s.l.), collected by N. Frutos, C.H.F. Perez, M. Morando, P. Frutos, L.J. Avila, and T. Avila (February 9, 2006); LJAMM-CNP 3683 (adult male) and 3684 (adult female) from Provincial Road 17, 36.4 km SE Corcovado, Futaleufú Department, Chubut Province, Argentina (43°33′43.8″S, 71°10′1.3″W, 816 m.a.s.l.), collected by N. Frutos, C.H.F. Perez, M. Morando, P. Frutos, L.J. Avila, and T. Avila (February 9, 2006); LJAMM-CNP 4684–4685, 4687 (adult females), and 4686 (adult male) from Provincial Road 53, 40 km S from junction to National Road 25, Tehuelches Department, Chubut Province, Argentina (43°58′25.2″S, 70°22′5.4″W, 797 m.a.s.l.), collected by L.J. Avila and C.H.F. Perez (February 2, 2004); LJAMM-CNP 6501 (adult male) from Provincial Road 44, 35.9 km S Corcovado, Cushamen Department, Chubut Province, Argentina (43°45′56.4″S, 71°23′52.4″W, 959 m.a.s.l.), collected by L.J. Avila, N. Frutos, and M. Kozykariski (March 19, 2006); LJAMMCNP 8877 (adult female) from National Road 40, 70.6 km N Tecka, 10.8 km S Nahuel Pan, Futaleufú Department, Chubut Province, Argentina (43°59′24.7″S, 71°5′57.6″W, 745 m.a.s.l.), collected by L.J. Avila, M.F. Breitman, and N. Feltrin (December 15, 2007); LJAMM-CNP 8891 (adult female) from Provincial Road 40, 2 km N Esquel airport, Cushamen Department, Chubut Province, Argentina (42°51′57.3″S, 71°7′54.3″W, 819 m.a.s.l.), collected by L.J. Avila, M.F. Breitman, and N. Feltrin (December 16, 2007); LJAMM-CNP 9183 (adult female) from National Road 40, 16.1 km S Tecka, Languiñeo Department, Chubut Province, Argentina (43°37′47.7″S, 70°50′27.2″W, 943 m.a.s.l.), collected by L.J. Avila, M.F. Breitman, and N. Feltrin (December 15, 2007); LJAMM-CNP 11098 (adult male) from Provincial Road 13, 20.3 km N Colan Conhué, road to Paso del Sapo, Languiñeo Department, Chubut Province, Argentina (43°4′16.8″S, 69°53′47.6″W, 992 m.a.s.l.), collected by L.J. Avila and M. Nicola (November 5, 2008); LJAMM-CNP 13083 (adult male), 13084 – 13086 (adult females), and MLP. R 6827 (ex LJAMM-CNP 13088, juvenile) from 6 Hermanos plant, 10 km N-NE from junction with Provincial Road 25, road to Provincial Road 62, Pocitos de Quichaura, Languiñeo Department, Chubut Province, Argentina (43°26′23.9″S, 70°0′12.7″W, 743 m.a.s.l.) collected by L.J. Avila, M. Kozykariski, M.F. Breitman, and R. Martinez (March 16, 2010); LJAMMCNP 13106 – 13108 (adult males) and 13110 (adult female) from Provincial Road 13, 18.8 km N Colan Conhué, Languiñeo Department, Chubut Province, Argentina (43°4′52.5″S, 69°53′58.1″W, 1011 m.a.s.l.), collected by L.J. Avila, M. Kozykariski, M.F. Breitman, and R. Martinez (March 16, 2010); LJAMM-CNP 13114 (adult male) from Blanca lagoon, Provincial Road 13, between Colan Conhué and Paso del Sapo, 32 km N Colan Conhué, Languiñeo Department, Chubut Province, Argentina (42°57′14.4″S, 69°55′47.7″W, 935 m.a.s.l.), collected by L.J. Avila, M. Kozykariski, M.F. Breitman, and R. Martinez (March 16, 2010); LJAMM-CNP 15602 (adult female) from Provincial Road 63, 21.1 km NE José de San Martín, Tehuelches Department, Chubut Province, Argentina (43°54′31.3″S, 70°18′45.9″W, 1072 m.a.s.l.), collected by M.A. González – Marín, C.H.F. Perez, and L.J. Avila (October 10, 2013); LJAMM-CNP 17011, 17270, 17271, MLP. R 6829 (ex LJAMM-CNP 16794) (adult males), and MLP. R 6830 (ex LJAMM-CNP 16800) (adult female) from National Road 40, 50.9 km N from junction with Provincial Road 19, road to Río Pico, Pampa del Tepuel, Languiñeo Department, Chubut Province, Argentina (43°38′8.9″S, 70°50′30.5″W, 941 m.a.s.l.), collected by L.J. Avila (January 30, 2016); MLP. R 6831 (ex LJAMM-CNP 17007) (juvenile) from National Road 40, 39 km N Gobernador Costa, between Putrachoique and La Paulina ranch, eastern slope of Cordón de Putrachoique, Tehuelches Department, Chubut Province, Argentina (43°51′22.5″S, 70°54′57.4″W, 859 m.a.s.l.), collected by L.J. Avila (January 30, 2016); LJAMM-CNP 17019–17020 (adult males), 17021 (adult female), MLP. R 6832 (ex LJAMM-CNP 17022), and 6833 (ex LJAMM-CNP 17023) (juveniles) from Provincial Road 17, 14.4 km S Provincial Road 40, Futaleufú Department, Chubut Province, Argentina (43°34′27.4″S, 70°54′7.4″W, 865 m.a.s.l.), collected by L.J. Avila (January 30, 2016); LJAMM-CNP 19206 (adult female) from National Road 40, 22 km N from junction with Provincial Road 19, 38 km N Gobernador Costa, Tehuelches Department, Chubut Province, Argentina (43°52′5.84″S, 70°54′45.83″W, 858 m.a.s.l.), collected by L.J. Avila and K.I. Sánchez (February 23, 2020); LJAMM-CNP 19207 (adult male) and 19227 (adult female) from National Road 40, 68.6 km N Gobernador Costa, near Tecka, Languiñeo Department, Chubut Province, Argentina (43°37′29.57″S, 70°50′26.38″W, 938 m.a.s.l.), collected by L.J. Avila and K.I. Sánchez (February 23, 2020). Besides the holotype and adult paratypes, we included 12 juvenile specimens in molecular analyzes (Appendix 2). Diagnosis. Liolaemus attenboroughi sp. nov. belongs to the Liolaemus kingii group by having a generally dark background coloration, slightly stout body, longer distance between snout and vent, and higher number of scales around midbody compared to members of the L. lineomaculatus and L. magellanicus groups (Scolaro & Cei 1997; Breitman et al. 2013; Avila et al. 2020). Liolaemus attenboroughi sp. nov. has imbricated scales, not tridentated, its dorsal pattern is characterized by a conspicuous vertebral line blended with perpendicular well-defined lines that are wider in the vertebral portion of the body, becoming narrow in the lateral zone. Significant differences in morphometric and meristic attributes are shown in Table 2. Summary statistics of each variable are shown in Tables 4 and 5. Overall, body size dimensions were smaller in Liolaemus attenboroughi sp. nov. compared to several members of the kingii group, mainly L. archeforus, L. baguali, L. gallardoi, L. kingii, L. sarmientoi, L. somuncurae, L. tari, and L. tristis (three to six significantly different variables). The only exceptions included a higher head compared to L. kingii and L. tristis, and a longer tibia-fibula compared to L. scolaroi. Meristic differences were mainly concentrated in the number of scales around midbody, being higher in Liolaemus attenboroughi sp. nov. compared to L. archeforus, L. escarchadosi, L. gallardoi, L. sarmientoi, L. scolaroi, L. tristis, L. uptoni, and L. zullyae. The least amount of significant differences were found with L. chacabucoense (auditory meatus width), L. escarchadosi (number of scales around midbody), and L. zullyae (auditory meatus width and number of scales around midbody). Description of the holotype. Body size dimensions (mm.): snout vent length 71, tail length 89, head length 16.1 (from the anterior border of the tympanum to the snout tip), head height 8.83 (at the anterior border of the tympanum), head width 12.76 (between the anterior borders of the auditory openings), forelimb length (radiusulna) 17.97, tibia-fibula length 11.92, foot length 19.34 (between the ankle and the insertion of the claw on the fourth toe), axilla-groin distance 36.43, snout length 5.2 (between the posterior border of the canthal scale and the tip of the snout), rostral-nasal distance 2.47 (between the anterior border of the nare and the tip of the snout), orbit-tympanum distance 5.88 (between the posterior insertion of the superciliaries and the anterior border of the tympanum), auditory meatus higher (2.92) than wide (2.07), anterior distance between orbits 5.44 (between the anterior insertions of the superciliaries), posterior distance between orbits 7.8 (between the posterior insertions of the superciliaries). Orbit size: 3.78 (width)/2.52 (height). ......continued on the next page Folds: slight nuchal, postauricular, and longitudinal distinct, supra-auricular and oblique neck absent, dorsolateral slightly evident. Supernumerary antegular very slight, antegular, and gular evident and incomplete, antehumeral evident. Squamation: Dorsal head scales bulged and smooth, 14 between occiput (at the level of the anterior border of the tympanum to the rostral). Rostral wider (3.61 mm.) than high (1.36 mm.). Two postrostrals, four internasals, three frontonasals. Three canthals on each side, anteriors in contact with nasal and frontonasal scales, posterior larger than anteriors. Five prefrontals, two on each side, separated by a melanic rhomboidal scale. Frontal scale longitudinally divided in two. Five scales between frontal and rostral scales. Supraorbital semicircles complete. Seven scales in contact with the interparietal, parietal eye in the anterior half of the scale. Parietals bulged, irregularly shaped; left larger than right. Three rows of supraoculars (on both sides), medial row of enlarged scales. Seven superciliaries on each side, anteriors elongated. Dorsal and lateral scales of neck granular. Eight/seven scales surrounding nasals. Nasals separated form rostral scale by anterior lorilabial and post-rostral scales. Loreal region flat. Six/seven lorilabials, three/four in contact with subocular. One preocular on each side. Subocular scale elongate, complete. Seven supralabials on each side, fourth scale curved upward posteriorly (on both sides). Temporals juxtaposed, smooth, and protruding, few with one scale organ. Orbit with 14/18 upper ciliares and 12/11 lower ciliaries. Three outwardly projecting scales along the anterior border of the auditory meatus. Mental wider (3.51 mm.) than high (1.34 mm.), followed posteriorly by two post-mentals and two rows of 3/3 chinshields. Four scales in contact with the mental. Six infralabials on each side. Scale organs mainly present in the anterior head region. Throat scales between chinshields subimbricated, imbricated toward the auditory meatus. Twenty/15 gulars between antegular and gular folds. Thirty-one/27 scales along longitudinal fold, between auditory meatus and antehumeral fold. Loreal, lorilabials, infralabials, rostral, post-rostrals, nasals, internasals, frontonasals, and prefrontals with conspicuous scale organs. Dorsal body scales sublanceolated, imbricated, distinctly keeled in the area between axila and groin, weakly keeled in the anterior and posterior areas. Seventy-seven dorsal scales, between interparietal (not counting it) and posterior surface of thighs. Twenty-seven longitudinal keeled scales rows, between dorsolateral folds. Scales become slightly keeled to smooth in the flanks, small, granular, and subimbircated around limb insertions. Eighty-one scales around midbody. Ventral scales wider than dorsals, smooth and rounded, juxtaposed. One-hundred and one scales between mental (not counting it) and precloacal pores. Eight precloacal pores on squared scales. Margin of cloaca distinctly cuadrangular. Suprabrachials imbricated, slightly keeled, infrabrachials subimbricated and granular. Prebrachials and postbrachials subimbricate, smooth. Supraantebrachials and infraantebrachials subimbricate, smooth. Preantebrachials and postantebrachials imbricate and smooth. Supracarpals imbricate, smooth; inframetacarpals imbricate and smooth, smaller than supracarpals. Supradigitals of manus smooth, wider than long; subdigitals with three keels, each terminating in a short blunt mucron, more evident in lateral keels; numbering: I: 9, II: 13; III: 17; IV: 18; V: 10. Claws slightly curved, light gray on ventral side, darker on dorsal side. Suprafemorals imbricated, slightly keeled, subtriangular on the anterior half, granular on the posterior half; infrafemorals imbricated and smooth. Prefemorals subimbricated, smooth, postfemorals granulated. Supratibials juxtaposed to subimbricated, some slightly keeled, infratibials subimbricate, smooth, similar in size to supratibials. Pretibials subimbricated, slightly keeled to granular; posttibials imbricated and smooth. Supratarsals imbricate, smooth; infratarsals imbricate and slightly keeled, smaller than supracarpals. Supradigitals of foot imbricated, slightly keeled; subdigitals with two to three keels, slightly mucronated; numbering: I: 11, II: 13; III: 18; IV: 23; V: 14. Claws slightly curved, light gray on ventral side, darker on dorsal side. Tail complete, quadrangular in cross section near the cloaca, the remaining becomes oval to round. Slight bulges on the ventral side of the proximal region, indicating the location of inverted hemipenes. Caudal scales constituting conspicuous annuli. Dorsal caudal scales distinctly keeled, imbricated, and mucronated. Sublanceolated on the proximal section, subcuadrangular on the middle section and rectangular on the distal section. Lateral scales keeled to slightly keeled. Ventral caudal scales smooth on the proximal portion, slightly keeled to keeled on the distal portion. Color of holotype in life. Observations were made in sunlight. Dorsal background color of head Umber (#654F41), neck, trunk, tail, and limbs Black Olive (#3D3C41). Dorsal head surface with some scattered Black Olive lines and spots. Dorsal pattern of central streaks and lateral dot bands. Streaks are Dark Vanilla (#D1C8A7) in the anterior half through Dark Khaki in the posterior half; dots constituted by 4–6 Dark Vanilla scales in the anterior half, Rose Taupe (#955E57) in the posterior half. Bands becoming a solid vertebral line in the region of thigh insertions through the base of the tail. On the tail, vertebral line becomes a series of irregular Aztec Gold (#C6A157) rings to the tip of the tail. Lateral head region Umber. Lateral body region background Black Olive, with regular and conspicuous Dark Khaki bands. Limbs with scattered spots and bands, Dark Vanilla in the forelimbs, Dark Khaki in the hindlimbs. Ventral background Bone (#DCDEC6). Mandible and gular region melanic, Gray (#81817A), with some interspersed Deer scales (#B37E5E). Melanic pattern turns into irregular lines in the chest region. Lower belly and femoral-tibial hind limbs Dark Khaki (#BEB069). Color of holotype in preservative. See Figure 4. Conspicuous bright colors disappearing after fixation, fading to darker tones. Dorsal pattern of central streaks Cultured (#F7F8F0), lateral spots Desert Sand (#E6D1A2). Mandible and gular region melanic, ventral region Pastel Gray (#DCD5B9). Variation. Morphological and meristic character variation in females and males of Liolaemus attenboroughi sp. nov. are shown in Table 1. Sexual dimorphism is present in all measurements, except rostral height and snout-vent length. Meristic attributes with sexual dimorphism include infradigital lamellae on the third finger and infralabial scales. Ventral variegation is present in most of the males and a few females (Figs. 6 and 7). Females in life present basically the same dorsal and lateral color pattern observed in males (Fig. 5), although they generally have a light brown background coloration. Paratypes LJAMM-CNP 11098 and 13114 (males) show a dorsal pattern of nearly complete transversal bands, resembling a L. kingii pattern. Geographic distribution. Liolaemus attenboroughi sp. nov. is known from the Patagonian Steppe of northwestern Chubut province, delimited in the north and east by the Chubut River and the west by the Andes mountain chain. Geographically, it is isolated from the remaining species of the L. kingii group (Fig. 1). Collection sites are located in four vegetation units (Oyarzabal et al. 2018; Fig. 8): (i) low steppe of Senecio algens and Oxalis compacta, dominated by camephytes and herbaceous hemicryptophytes (one locality); (ii) grass steppe dominated by Festuca pallescens (five localities; Fig. 8); (iii) grassy shrub-steppe, dominated by gramineous Pappostipa speciosa, P. humilis, Poa ligularis, and P. lanuginosa, and the shrubs Adesmia volckmannii and Berberis microphylla (nine localities); and (iv) serran shrub steppe dominated by Colliguaja integerrima (three localities). Natural history. Based on field observations and reports on related species (Cei 1986), Liolaemus attenboroughi sp. nov. is a viviparous and omnivorous species. Lizards were observed basking on rocks along roads or in the edge of medium size bushes. Other lizards found in syntopy were L. lineomaculatus, L. bibronii, L. boulengeri, and Diplolaemus aff. sexcinctus. Etimology. We name this new species in honor to Sir David F. Attenborough, English broadcaster, biologist, natural historian, and author, in recognition of his immense contribution to the public understanding and appreciation of the biodiversity, and the necessity of its protection. While Attenborough’s earlier work focused more on the marvels of our planet, his later work has been more vocal in support of environmental causes, advocating for mitigate climate change, limit human population growth, and switch to renewable energies., Published as part of Sánchez, Kevin I., Morando, Mariana & Avila, Luciano J., 2023, A new lizard species of the Liolaemus kingii group (Squamata: Liolaemidae) from northwestern Chubut province (Argentina), pp. 235-255 in Zootaxa 5264 (2) on pages 239-249, DOI: 10.11646/zootaxa.5264.2.5, http://zenodo.org/record/7838505, {"references":["Cei, J. M. (1975) Southern Patagonian iguanid lizards of the Liolaemus kingi group. Herpetologica, 31 (1), 109 - 116. https: // www. jstor. org / stable / 3891997","Cei, J. M. (1986) Monografie IV, Reptiles del centro, centro-oeste y sur de Argentina. Herpetofauna de las zonas aridas y semiaridas. Museo Regionale di Science Naturali Torino, 4, 1 - 527.","Minoli, I., Morando, M., Avila, L. J. (2015) Reptiles of Chubut province, Argentina: richness, diversity, conservation status and geographic distribution maps. ZooKeys, 498, 103 - 126. https: // doi. org / 10.3897 / zookeys. 498.7476","Scolaro, J. A. & Cei, J. M. (1997) Systematic status and relationships of Liolaemus species of the archeforus and kingii groups: A morphological and taxonumerical approach (Reptilia: Tropiduridae). dal Bollettino del Museo Regionale di Scienze Naturali, Torino, 15, 369 - 406.","Breitman, M. F., Morando, M. & Avila, L. J. (2013) Past and present taxonomy of the Liolaemus lineomaculatus section (Liolaemidae): is the morphological arrangement hypothesis valid? Zoological Journal of the Linnean Society, 168 (3), 612 - 668. https: // doi. org / 10.1111 / zoj. 12037","Avila, L. J., Gonzalez Marin, A., Troncoso-Palacios, J., Sanchez, K. I., Perez, C. H. F. & Morando, M. (2020) Naming the diversity: Taxonomy of current species of Patagonian lizards. In: Morando, M. & Avila, L. J. (Eds.), Lizards of Patagonia. Springer International Publishing, Cham, pp. 123 - 188. https: // doi. org / 10.1007 / 978 - 3 - 030 - 42752 - 8 _ 7","Oyarzabal, M., Clavijo, J., Oakley, L., Biganzoli, F., Tognetti, P., Barberis, I., Maturo, H. M., Aragon, R., Campanello, P. I., Prado, D., Oesterheld, M. & Leon, R. J. C. (2018) Unidades de vegetacion de la Argentina. Ecologia Austral, 28 (1), 040 - 063. https: // doi. org / 10.25260 / EA. 18.28.1.0.399"]}

Liolaemus attenboroughi, new species 1975 Liolaemus kingi Cei, 1975 Herpetologica 31(1): 109–116. 1986 Liolaemus kingi Cei, 1986 Museo Regionale di Science Naturali Torino, Monografie 4: 1–527. 2015 Liolaemus kingii Minoli et al., 2015 Zookeys 498: 103–126. Holotype. LJAMM-CNP 16782 (Fig. 4): Adult male. Locality: National Road 40, 39 km N of Gobernador Costa, between Putrachoique and La Paulina ranch, eastern slope of Cordón de Putrachoique, Tehuelches Department, Chubut Province, Argentina (43°51′22.5″S, 70°54′57.4″W, 859 m.a.s.l.). Collector: L.J.Avila.Date: January 30,2018. Paratypes. See Figures 5, 6, and 7. LJAMM-CNP 16781, 16784, MLP. R 6828 (ex LJAMM-CNP 16783) (adult males), and LJAMM-CNP 16786 (adult female), same data as holotype; LJAMM-CNP 3678 (adult male) and 3679 (adult female) from Provincial Road 12, La Cancha pier, Cushamen Department, Chubut Province, Argentina (42°47′47.3″S, 70°57′30.2″W, 762 m.a.s.l.), collected by N. Frutos, C.H.F. Perez, M. Morando, P. Frutos, L.J. Avila, and T. Avila (February 8, 2006); LJAMM-CNP 3680, 3702 (adult females), and 3701 (adult male) from Provincial Road 17, 52.5 km SE Corcovado, Languiñeo Department, Chubut Province, Argentina (43°37′42.5″S, 70°59′49.8″W, 770 m.a.s.l.), collected by N. Frutos, C.H.F. Perez, M. Morando, P. Frutos, L.J. Avila, and T. Avila (February 9, 2006); LJAMM-CNP 3683 (adult male) and 3684 (adult female) from Provincial Road 17, 36.4 km SE Corcovado, Futaleufú Department, Chubut Province, Argentina (43°33′43.8″S, 71°10′1.3″W, 816 m.a.s.l.), collected by N. Frutos, C.H.F. Perez, M. Morando, P. Frutos, L.J. Avila, and T. Avila (February 9, 2006); LJAMM-CNP 4684–4685, 4687 (adult females), and 4686 (adult male) from Provincial Road 53, 40 km S from junction to National Road 25, Tehuelches Department, Chubut Province, Argentina (43°58′25.2″S, 70°22′5.4″W, 797 m.a.s.l.), collected by L.J. Avila and C.H.F. Perez (February 2, 2004); LJAMM-CNP 6501 (adult male) from Provincial Road 44, 35.9 km S Corcovado, Cushamen Department, Chubut Province, Argentina (43°45′56.4″S, 71°23′52.4″W, 959 m.a.s.l.), collected by L.J. Avila, N. Frutos, and M. Kozykariski (March 19, 2006); LJAMMCNP 8877 (adult female) from National Road 40, 70.6 km N Tecka, 10.8 km S Nahuel Pan, Futaleufú Department, Chubut Province, Argentina (43°59′24.7″S, 71°5′57.6″W, 745 m.a.s.l.), collected by L.J. Avila, M.F. Breitman, and N. Feltrin (December 15, 2007); LJAMM-CNP 8891 (adult female) from Provincial Road 40, 2 km N Esquel airport, Cushamen Department, Chubut Province, Argentina (42°51′57.3″S, 71°7′54.3″W, 819 m.a.s.l.), collected by L.J. Avila, M.F. Breitman, and N. Feltrin (December 16, 2007); LJAMM-CNP 9183 (adult female) from National Road 40, 16.1 km S Tecka, Languiñeo Department, Chubut Province, Argentina (43°37′47.7″S, 70°50′27.2″W, 943 m.a.s.l.), collected by L.J. Avila, M.F. Breitman, and N. Feltrin (December 15, 2007); LJAMM-CNP 11098 (adult male) from Provincial Road 13, 20.3 km N Colan Conhué, road to Paso del Sapo, Languiñeo Department, Chubut Province, Argentina (43°4′16.8″S, 69°53′47.6″W, 992 m.a.s.l.), collected by L.J. Avila and M. Nicola (November 5, 2008); LJAMM-CNP 13083 (adult male), 13084 – 13086 (adult females), and MLP. R 6827 (ex LJAMM-CNP 13088, juvenile) from 6 Hermanos plant, 10 km N-NE from junction with Provincial Road 25, road to Provincial Road 62, Pocitos de Quichaura, Languiñeo Department, Chubut Province, Argentina (43°26′23.9″S, 70°0′12.7″W, 743 m.a.s.l.) collected by L.J. Avila, M. Kozykariski, M.F. Breitman, and R. Martinez (March 16, 2010); LJAMMCNP 13106 – 13108 (adult males) and 13110 (adult female) from Provincial Road 13, 18.8 km N Colan Conhué, Languiñeo Department, Chubut Province, Argentina (43°4′52.5″S, 69°53′58.1″W, 1011 m.a.s.l.), collected by L.J. Avila, M. Kozykariski, M.F. Breitman, and R. Martinez (March 16, 2010); LJAMM-CNP 13114 (adult male) from Blanca lagoon, Provincial Road 13, between Colan Conhué and Paso del Sapo, 32 km N Colan Conhué, Languiñeo Department, Chubut Province, Argentina (42°57′14.4″S, 69°55′47.7″W, 935 m.a.s.l.), collected by L.J. Avila, M. Kozykariski, M.F. Breitman, and R. Martinez (March 16, 2010); LJAMM-CNP 15602 (adult female) from Provincial Road 63, 21.1 km NE José de San Martín, Tehuelches Department, Chubut Province, Argentina (43°54′31.3″S, 70°18′45.9″W, 1072 m.a.s.l.), collected by M.A. González – Marín, C.H.F. Perez, and L.J. Avila (October 10, 2013); LJAMM-CNP 17011, 17270, 17271, MLP. R 6829 (ex LJAMM-CNP 16794) (adult males), and MLP. R 6830 (ex LJAMM-CNP 16800) (adult female) from National Road 40, 50.9 km N from junction with Provincial Road 19, road to Río Pico, Pampa del Tepuel, Languiñeo Department, Chubut Province, Argentina (43°38′8.9″S, 70°50′30.5″W, 941 m.a.s.l.), collected by L.J. Avila (January 30, 2016); MLP. R 6831 (ex LJAMM-CNP 17007) (juvenile) from National Road 40, 39 km N Gobernador Costa, between Putrachoique and La Paulina ranch, eastern slope of Cordón de Putrachoique, Tehuelches Department, Chubut Province, Argentina (43°51′22.5″S, 70°54′57.4″W, 859 m.a.s.l.), collected by L.J. Avila (January 30, 2016); LJAMM-CNP 17019–17020 (adult males), 17021 (adult female), MLP. R 6832 (ex LJAMM-CNP 17022), and 6833 (ex LJAMM-CNP 17023) (juveniles) from Provincial Road 17, 14.4 km S Provincial Road 40, Futaleufú Department, Chubut Province, Argentina (43°34′27.4″S, 70°54′7.4″W, 865 m.a.s.l.), collected by L.J. Avila (January 30, 2016); LJAMM-CNP 19206 (adult female) from National Road 40, 22 km N from junction with Provincial Road 19, 38 km N Gobernador Costa, Tehuelches Department, Chubut Province, Argentina (43°52′5.84″S, 70°54′45.83″W, 858 m.a.s.l.), collected by L.J. Avila and K.I. Sánchez (February 23, 2020); LJAMM-CNP 19207 (adult male) and 19227 (adult female) from National Road 40, 68.6 km N Gobernador Costa, near Tecka, Languiñeo Department, Chubut Province, Argentina (43°37′29.57″S, 70°50′26.38″W, 938 m.a.s.l.), collected by L.J. Avila and K.I. Sánchez (February 23, 2020). Besides the holotype and adult paratypes, we included 12 juvenile specimens in molecular analyzes (Appendix 2). Diagnosis. Liolaemus attenboroughi sp. nov. belongs to the Liolaemus kingii group by having a generally dark background coloration, slightly stout body, longer distance between snout and vent, and higher number of scales around midbody compared to members of the L. lineomaculatus and L. magellanicus groups (Scolaro & Cei 1997; Breitman et al. 2013; Avila et al. 2020). Liolaemus attenboroughi sp. nov. has imbricated scales, not tridentated, its dorsal pattern is characterized by a conspicuous vertebral line blended with perpendicular well-defined lines that are wider in the vertebral portion of the body, becoming narrow in the lateral zone. Significant differences in morphometric and meristic attributes are shown in Table 2. Summary statistics of each variable are shown in Tables 4 and 5. Overall, body size dimensions were smaller in Liolaemus attenboroughi sp. nov. compared to several members of the kingii group, mainly L. archeforus, L. baguali, L. gallardoi, L. kingii, L. sarmientoi, L. somuncurae, L. tari, and L. tristis (three to six significantly different variables). The only exceptions included a higher head compared to L. kingii and L. tristis, and a longer tibia-fibula compared to L. scolaroi. Meristic differences were mainly concentrated in the number of scales around midbody, being higher in Liolaemus attenboroughi sp. nov. compared to L. archeforus, L. escarchadosi, L. gallardoi, L. sarmientoi, L. scolaroi, L. tristis, L. uptoni, and L. zullyae. The least amount of significant differences were found with L. chacabucoense (auditory meatus width), L. escarchadosi (number of scales around midbody), and L. zullyae (auditory meatus width and number of scales around midbody). Description of the holotype. Body size dimensions (mm.): snout vent length 71, tail length 89, head length 16.1 (from the anterior border of the tympanum to the snout tip), head height 8.83 (at the anterior border of the tympanum), head width 12.76 (between the anterior borders of the auditory openings), forelimb length (radiusulna) 17.97, tibia-fibula length 11.92, foot length 19.34 (between the ankle and the insertion of the claw on the fourth toe), axilla-groin distance 36.43, snout length 5.2 (between the posterior border of the canthal scale and the tip of the snout), rostral-nasal distance 2.47 (between the anterior border of the nare and the tip of the snout), orbit-tympanum distance 5.88 (between the posterior insertion of the superciliaries and the anterior border of the tympanum), auditory meatus higher (2.92) than wide (2.07), anterior distance between orbits 5.44 (between the anterior insertions of the superciliaries), posterior distance between orbits 7.8 (between the posterior insertions of the superciliaries). Orbit size: 3.78 (width)/2.52 (height). ......continued on the next page Folds: slight nuchal, postauricular, and longitudinal distinct, supra-auricular and oblique neck absent, dorsolateral slightly evident. Supernumerary antegular very slight, antegular, and gular evident and incomplete, antehumeral evident. Squamation: Dorsal head scales bulged and smooth, 14 between occiput (at the level of the anterior border of the tympanum to the rostral). Rostral wider (3.61 mm.) than high (1.36 mm.). Two postrostrals, four internasals, three frontonasals. Three canthals on each side, anteriors in contact with nasal and frontonasal scales, posterior larger than anteriors. Five prefrontals, two on each side, separated by a melanic rhomboidal scale. Frontal scale longitudinally divided in two. Five scales between frontal and rostral scales. Supraorbital semicircles complete. Seven scales in contact with the interparietal, parietal eye in the anterior half of the scale. Parietals bulged, irregularly shaped; left larger than right. Three rows of supraoculars (on both sides), medial row of enlarged scales. Seven superciliaries on each side, anteriors elongated. Dorsal and lateral scales of neck granular. Eight/seven scales surrounding nasals. Nasals separated form rostral scale by anterior lorilabial and post-rostral scales. Loreal region flat. Six/seven lorilabials, three/four in contact with subocular. One preocular on each side. Subocular scale elongate, complete. Seven supralabials on each side, fourth scale curved upward posteriorly (on both sides). Temporals juxtaposed, smooth, and protruding, few with one scale organ. Orbit with 14/18 upper ciliares and 12/11 lower ciliaries. Three outwardly projecting scales along the anterior border of the auditory meatus. Mental wider (3.51 mm.) than high (1.34 mm.), followed posteriorly by two post-mentals and two rows of 3/3 chinshields. Four scales in contact with the mental. Six infralabials on each side. Scale organs mainly present in the anterior head region. Throat scales between chinshields subimbricated, imbricated toward the auditory meatus. Twenty/15 gulars between antegular and gular folds. Thirty-one/27 scales along longitudinal fold, between auditory meatus and antehumeral fold. Loreal, lorilabials, infralabials, rostral, post-rostrals, nasals, internasals, frontonasals, and prefrontals with conspicuous scale organs. Dorsal body scales sublanceolated, imbricated, distinctly keeled in the area between axila and groin, weakly keeled in the anterior and posterior areas. Seventy-seven dorsal scales, between interparietal (not counting it) and posterior surface of thighs. Twenty-seven longitudinal keeled scales rows, between dorsolateral folds. Scales become slightly keeled to smooth in the flanks, small, granular, and subimbircated around limb insertions. Eighty-one scales around midbody. Ventral scales wider than dorsals, smooth and rounded, juxtaposed. One-hundred and one scales between mental (not counting it) and precloacal pores. Eight precloacal pores on squared scales. Margin of cloaca distinctly cuadrangular. Suprabrachials imbricated, slightly keeled, infrabrachials subimbricated and granular. Prebrachials and postbrachials subimbricate, smooth. Supraantebrachials and infraantebrachials subimbricate, smooth. Preantebrachials and postantebrachials imbricate and smooth. Supracarpals imbricate, smooth; inframetacarpals imbricate and smooth, smaller than supracarpals. Supradigitals of manus smooth, wider than long; subdigitals with three keels, each terminating in a short blunt mucron, more evident in lateral keels; numbering: I: 9, II: 13; III: 17; IV: 18; V: 10. Claws slightly curved, light gray on ventral side, darker on dorsal side. Suprafemorals imbricated, slightly keeled, subtriangular on the anterior half, granular on the posterior half; infrafemorals imbricated and smooth. Prefemorals subimbricated, smooth, postfemorals granulated. Supratibials juxtaposed to subimbricated, some slightly keeled, infratibials subimbricate, smooth, similar in size to supratibials. Pretibials subimbricated, slightly keeled to granular; posttibials imbricated and smooth. Supratarsals imbricate, smooth; infratarsals imbricate and slightly keeled, smaller than supracarpals. Supradigitals of foot imbricated, slightly keeled; subdigitals with two to three keels, slightly mucronated; numbering: I: 11, II: 13; III: 18; IV: 23; V: 14. Claws slightly curved, light gray on ventral side, darker on dorsal side. Tail complete, quadrangular in cross section near the cloaca, the remaining becomes oval to round. Slight bulges on the ventral side of the proximal region, indicating the location of inverted hemipenes. Caudal scales constituting conspicuous annuli. Dorsal caudal scales distinctly keeled, imbricated, and mucronated. Sublanceolated on the proximal section, subcuadrangular on the middle section and rectangular on the distal section. Lateral scales keeled to slightly keeled. Ventral caudal scales smooth on the proximal portion, slightly keeled to keeled on the distal portion. Color of holotype in life. Observations were made in sunlight. Dorsal background color of head Umber (#654F41), neck, trunk, tail, and limbs Black Olive (#3D3C41). Dorsal head surface with some scattered Black Olive lines and spots. Dorsal pattern of central streaks and lateral dot bands. Streaks are Dark Vanilla (#D1C8A7) in the anterior half through Dark Khaki in the posterior half; dots constituted by 4–6 Dark Vanilla scales in the anterior half, Rose Taupe (#955E57) in the posterior half. Bands becoming a solid vertebral line in the region of thigh insertions through the base of the tail. On the tail, vertebral line becomes a series of irregular Aztec Gold (#C6A157) rings to the tip of the tail. Lateral head region Umber. Lateral body region background Black Olive, with regular and conspicuous Dark Khaki bands. Limbs with scattered spots and bands, Dark Vanilla in the forelimbs, Dark Khaki in the hindlimbs. Ventral background Bone (#DCDEC6). Mandible and gular region melanic, Gray (#81817A), with some interspersed Deer scales (#B37E5E). Melanic pattern turns into irregular lines in the chest region. Lower belly and femoral-tibial hind limbs Dark Khaki (#BEB069). Color of holotype in preservative. See Figure 4. Conspicuous bright colors disappearing after fixation, fading to darker tones. Dorsal pattern of central streaks Cultured (#F7F8F0), lateral spots Desert Sand (#E6D1A2). Mandible and gular region melanic, ventral region Pastel Gray (#DCD5B9). Variation. Morphological and meristic character variation in females and males of Liolaemus attenboroughi sp. nov. are shown in Table 1. Sexual dimorphism is present in all measurements, except rostral height and snout-vent length. Meristic attributes with sexual dimorphism include infradigital lamellae on the third finger and infralabial scales. Ventral variegation is present in most of the males and a few females (Figs. 6 and 7). Females in life present basically the same dorsal and lateral color pattern observed in males (Fig. 5), although they generally have a light brown background coloration. Paratypes LJAMM-CNP 11098 and 13114 (males) show a dorsal pattern of nearly complete transversal bands, resembling a L. kingii pattern. Geographic distribution. Liolaemus attenboroughi sp. nov. is known from the Patagonian Steppe of northwestern Chubut province, delimited in the north and east by the Chubut River and the west by the Andes mountain chain. Geographically, it is isolated from the remaining species of the L. kingii group (Fig. 1). Collection sites are located in four vegetation units (Oyarzabal et al. 2018; Fig. 8): (i) low steppe of Senecio algens and Oxalis compacta, dominated by camephytes and herbaceous hemicryptophytes (one locality); (ii) grass steppe dominated by Festuca pallescens (five localities; Fig. 8); (iii) grassy shrub-steppe, dominated by gramineous Pappostipa speciosa, P. humilis, Poa ligularis, and P. lanuginosa, and the shrubs Adesmia volckmannii and Berberis microphylla (nine localities); and (iv) serran shrub steppe dominated by Colliguaja integerrima (three localities). Natural history. Based on field observations and reports on related species (Cei 1986), Liolaemus attenboroughi sp. nov. is a viviparous and omnivorous species. Lizards were observed basking on rocks along roads or in the edge of medium size bushes. Other lizards found in syntopy were L. lineomaculatus, L. bibronii, L. boulengeri, and Diplolaemus aff. sexcinctus. Etimology. We name this new species in honor to Sir David F. Attenborough, English broadcaster, biologist, natural historian, and author, in recognition of his immense contribution to the public understanding and appreciation of the biodiversity, and the necessity of its protection. While Attenborough’s earlier work focused more on the marvels of our planet, his later work has been more vocal in support of environmental causes, advocating for mitigate climate change, limit human population growth, and switch to renewable energies.