A new lizard of the Liolaemus montanus group that inhabits the hyperarid desert of southern Peru Author Valladares-Faúndez, Pablo Laboratorio de Zoología Integrativa, Departamento de Biología, Facultad de Ciencias, Universidad de Tarapacá, General Velásquez 1775, Arica, CHILE Author León, Pablo Franco Dirección de Investigación, Universidad Jorge Basadre Grohmann, Avenida Miraflores S / N, Ciudad Universitaria, Tacna, PERÚ Author Chipana, Cesar Jove Dirección de Investigación, Universidad Jorge Basadre Grohmann, Avenida Miraflores S / N, Ciudad Universitaria, Tacna, PERÚ Author Guzmán, Marco Navarro Servicio Nacional Forestal y de Fauna Silvestre, Ministerio de Agricultura y Riego, Tacna, PERÚ Author Ignacio-Apaza, Javier Dirección de Investigación, Universidad Jorge Basadre Grohmann, Avenida Miraflores S / N, Ciudad Universitaria, Tacna, PERÚ Author Musaja, César Cáceres Departamento de Biología, Facultad de Biología y Microbiología, Universidad Nacional Jorge Basadre Grohmann, Tacna, PERÚ Author Langstroth, Robert Área de Herpetología, Colección Boliviana de Fauna, Campus Universitario de Cota Cota, Facultad de Ciencias Puras y Naturales, Universidad Mayor de San Andrés, La Paz, Estado Plurinacional de Bolivia, BOLIVIA Author Aguilar-Kirigin, Álvaro Red de Investigadores en Herpetología, La Paz, Estado Plurinacional de Bolivia, BOLIVIA & Área de Herpetología, Colección Boliviana de Fauna, Campus Universitario de Cota Cota, Facultad de Ciencias Puras y Naturales, Universidad Mayor de San Andrés, La Paz, Estado Plurinacional de Bolivia, BOLIVIA Author Gutierrez, Roberto C. Museo de Historia Natural, Universidad Nacional de San Agustín de Arequipa, PERÚ Author Abdala, Cristián S. Consejo Nacional de Investigación Científicas y Técnicas (CONICET) - Unidad ejecutora Lillo (UEL) - Facultad de Ciencias Naturales e Instituto Miguel Lillo (IML), Universidad Nacional de Tucumán, San Miguel de Tucumán, ARGENTINA text Amphibian & Reptile Conservation 2021 e 278 2021-08-12 15 2 10 22 journal article 297525 10.5281/zenodo.11390110 123316e2-6ecf-4048-a78b-f602e2ad75a9 1525-9153 11390110 D8B4BDF6-C656-460B-83F9-321A8F75E77A Liolaemus basadrei sp. nov. ( Fig. 2A–D ) urn:lsid:zoobank.org:act: 08DEBE00-8856-445A-BBD5-CD2A8D3EC45B Holotype . HP20CBT, an adult male ( Fig. 2A–B ) from the east slope of an unnamed hill east of Locumba Valley , 17°44’38”S , 70°45’41”W ; 897 m , Jorge Basadre Province , Tacna Region , Peru ; collected on 25 January 2019 , Pablo Franco , Pablo Valladares-Faúndez , Cesar Chipana , Marco Navarro and Javier Ignacio collectors. Allotype . HP21CBT, an adult female ( Fig. 2C–D ), from the east slope of an unnamed hill east of Locumba Valley , 17°45’21”S , 70°45’51”W ; 761 m , Jorge Basadre Province , Tacna Region , Peru ; collected on 25 January 2019 , same collectors. Paratypes . Two adults : HP22CBT and HP23CBT, from the east slope of an unnamed hill east of Locumba Valley , one male and one female . From the high voltage tower to the Pan-American highway, on a steep slope ( 17°44’50”S , 70°46’06”W ); 970 m , same collectors . Diagnosis. Liolaemus basadrei sp. nov. belongs to the L. montanus group ( sensu Etheridge 1995 ; Abdala et al. 2020). This species differs from the species of the L. boulengeri group of the L. montanus group series by the absence of a patch of enlarged scales on the posterior thigh of the hind limb in the new species ( Etheridge 1995 ; Abdala 2007 ). In relation to the L. montanus group, L. basadrei sp. nov. differs from L. andinus , L. annectens , L. cazianae , L. chlorostictus , L. dorbignyi , L. duellmani , L. eleodori , L. erguetae , L. erroneus , L. etheridgei , L. evaristoi , L. fabiani , L. famatinae , L. fittkaui , L. forsteri , L. foxi , L. gracielae , L. griseus , L. hajeki , L. halonastes , L. huacahuasicus , L. huayra , L. inti , L. islugensis , L. jamesi , L. juanortizi , L. lenzi , L. melanogaster , L. montanus , L. molinai , L. multicolor , L. nigriceps , L. orko , L. ortizi , L. pachecoi , L. pantherinus , L. patriciaiturrae , L. pleopholis , L. poecilochromus , L. polystictus , L. pulcherrimus , L. puritamensis , L. qalaywa , L. robertoi , L. robustus , L. rosenmanni , L. ruibali , L. schmidti , L. scrocchii , L. signifer , L. tajzara , L. thomasi , L. vallecurensis , L. victormoralesii , L. vulcanus , and L. williamsi by possessing isognathus jaws and tail shorter than Snout-Vent Length (SVL). Of the remaining species, L. basadrei sp. nov. are robust lizards (SVL = 88.2 mm ) differing from L. andinus , L. anqapuka , L. audituvelatus , L. balagueri , L. cazianiae , L. chiribaya , L. duellmani , L. eleodori , L. erguetae , L. erroneus , L. etheridgei , L. evaristoi , L. fabiani , L. famatinae , L. fittkaui , L. foxi , L. gracielae , L. griseus , L. hajeki , L. halonastes , L. huacahuasicus , L. islugensis , L. molinai , L. montanus , L. multicolor , L. nazca , L. orko , L. omorfi , L. ortizi , L. pantherinus , L. poconchilensis , L. poecilochromus , L. porosus , L. pulcherrimus , L. reichei , L. robertoi , L. rosenmanni , L. ruibali , L. smidthi , L. stolzmanni , L. tajzara , L. thomasi , L. torresi , L. vallecurensis , and L. williamnsi which are smaller (SVL between 50–80 mm ). The dorsal scales on the body are smooth and subimbricate in Liolaemus basadrei sp. nov. , differing from species that have dorsal scales with an evident keel: L. aymararum , L. etheridgei , L. famatinae , L. fittkaui , L. griseus , L. huacahuaicus , L. montanus , L. orko , L. oritizi , L. polystictus , L. pulcherrimus , L. qalaywa , L. signifer , L. tajzara , L. thomasi , L. victormoralesi , and L. williamsi . Liolaemus insolitus is the most similar among these lizards to the new species, but it differs principally by the number of scales along the dorso-thoracic region (scales between occiput and anterior border of thigh, 63 in L. insolitus versus 86–89 in the new species), number of ventral scales ( 70–78 in L. insolitus versus 79–85 in the new species), and the dorsal pattern in L. insolitus has fewer dark red scales and more sky-blue scales. Fig 1. Phylogenetic tree obtained for the new species. Phylogenetic results indicate that L. basadrei belongs to the clade of L. reichei (Abdala et al. 2020) . L. basadrei sp. nov. differs from L. anqapuka , L. audituvelatus , L. balagueri , L. chiribaya , L. insolitus , L. nazca , L. poconchilensis , L. reichei , L. stolzmanni , and L. torresi because the latter have a smaller size (< 70 mm SVL) and the new species is over 88 mm . Liolaemus basadrei sp. nov. also differs from L. balagueri , L. chiribaya , L. insolitus , L. nazca , L. poconchilensis , L. reichei , and L. torresi by having a greater number of scales around the body (74–82 vs. <72) and a greater number of dorsal scales on the body (84–92 vs. <80). The number of ventral scales is greater than in L. balagueri , L. chiribaya , L. insolitus and L. nazca (79–85 vs. <79). The presence of blue scales on the body also differentiates it from species that do not have them: L. audituvelatus , L. balagueri , L. nazca , L. reichei , and L. torresi . Description of the holotype . Medium-sized lizard, robust body, limbs short and robust, head triangular and short, distinct from neck, widest across temporal region, 0.89 times wider (as measured across widest part of temporal region) than long (as measured from inferior apex of external auditory meatus to anterior surface of rostral). Snout short (as measured from tip of snout to anterior corner or orbit), 0.26 times head length, orbit (as measured along its greatest horizontal length) short, 0.17 times head length. Nasal region slightly swollen, convex in profile, rostral narrow, 2.8 times wider than high, bordered by three postrostrals, semirectangular and pentagonal, external ones of greater size. Rostral scale in contact with a lorilabial and a supralabial scale on each side. Four hexagonal, irregular, and elongated internasals, external pair meeting nasals. Five medium and irregular scales between postrostral and internasal. Nasal scales larger, in contact with one postrostral, one lorilabial, one internasal, and two irregular postnasals, and a medium scale between internasal and postrostral. Nasal is separated from rostral and anterior supralabials by anterior lorilabials. Posterior nasal rounded and its anterior part is angled. Nostril oriented posterolaterally. Dorsal head scales larger, differentiated, convex; frontonasal region convex in profile. Twentyone irregular scales in frontonasal region, five irregular, convex and smooth prefrontals. Frontals and postfrontals fragmented and irregular. Two postfrontals meet to interparietal, which is slightly smaller than adjacent parietals, irregular, bordered by eight scales, with a distinct “eye” that corresponds to pineal organ ( Fig. 3A ). Elongated, convex and irregular parietals, posterior to interparietal. Supratemporal region smooth, irregular, and convex. Temporals larger, convex, juxtaposed, 11 between postocular and anterior margin of ear, 0.43 times head length. External auditory meatus large, rounded, 2 times higher than wide, bordered by irregular scales, smaller anteriorly, one largest on the upper side and not differentiated from posterior temporals, with small interstitial granules. Orbitals 0.17 times head length. Supraocular regions large, scales medium size, eight on each side, 4–5 in a horizontal line across widest part of supraocular region between superciliaries and frontals. Fifteen scales form an irregular circum-orbital semicircle. Seven superciliaries larger, not keeled, four anterior, two posterior, and one interciliar. Palpebrals small, smooth, convex and juxtaposed, 11 inner rectangular ciliaries, outer ciliaries of lower lid 12, outer ciliaries of upper lid 11, third ciliary and three posterior ciliaries triangular, but not as projecting as those of lower lid, those in middle of lid more nearly rectangular, not projecting. One preocular wider than subocular, pentagonal, preceded anteriorly by a large canthal. Subocular elongated, about 8 times longer than high and postocular elongate but shorter than preocular and subocular. Eleven lorilabials, a row of small scales between the subocular and lorilabials that start from the loreal scales. Anterior lorilabials rectangular, posteriors irregular and convex. Six irregular loreals. Ten supralabials, equal in size to lorilabials. No supralabials in contact with subocular, and one lorilabial in contact with subocular ( Fig. 3B ). Mental large, 1.1 times as wide as rostral, bordered by two infralabials and two postmentals, not in contact with anterior sublabials. Four postmentals on each side, infralabials six, gulars medium size, smooth, semitriangular, convex, imbricate ( Fig. 3C ). Ventral scales triangular, similar in size to dorsal scales, imbricate and smooth. Pectoral scales imbricate and triangular, on the sides are quadrangular. Posterior abdominal scales semirectangular. Scales of precloacal region imbricated and rounded, but wider than long. Six orange precloacal pores. Dorsal scales of neck small, smoothly overlapping, slightly concave, smooth and triangular, with interstitial granules. Dorsal scales of body larger, rounded or semicircular, smooth and subimbricate, similar to the lateral scales. Scales around midbody 79. Middorsal scales from occiput to point even with anterior margin of thigh 92. Lumbar scales wider than long, similar in size but less imbricated than dorsal scales and with interstitial granules. On the sides of the body, scales are quadrangular. Fig. 2. Dorsal (A) and ventral (B) views of holotype specimen collected in Valle de Locumba, Jorge Basadre Province, Region Tacna, Peru. Dorsal (C) and ventral (D) views of allotype specimen collected in Valle de Locumba, Jorge Basadre Province, Region Tacna, Peru. Lateral nuchal skin folds well-developed and complex. Two short folds, one originating at superior and other at inferior margin of auditory meatus, converging posteriorly to form a V-shaped fold, continuing posteriorly as longitudinal neck fold, intercepted by oblique neck fold and antehumeral fold, which reaches half of body. A fold born in the armpit, projects to the groin. Scales of lateral neck flat or slightly concave, nonoverlapping. Below the fold, triangular scales are slightly imbricate, similar in size to the dorsal neck. Limbs robust and short. Adpressed hindlimbs reach only middle of body. Forelimbs 0.32 times SVL and hindlimbs 0.52 times SVL . Scales of the base of the arm similar to those of the neck. Brachial scales smooth, triangular and imbricate, larger in size than dorsal body scales. Antebrachials tend to be semirectangular and smooth. Elbow scales semitriangular, and wider than long. Preantebrachials flat, smaller, rounded, and juxtaposed, with interstitial granules. Suprafemorals and postfemorals larger and triangular, smooth and imbricate. Prefemorals small, smooth, convex, juxtaposed. Supratibials and pretibials longer than wide, imbricate, with interstitial granules. Infratibials smooth, larger, triangular, and imbricated. Supratarsals large, smooth, triangular, and imbricate. Subdigital lamellae of fourth toe 25, with distal margin slightly tridentate, claws long and slender. Supracarpals large, smooth, imbricate, wide than longer. Infracarpals imbricate, somewhat projecting, mucronate, supradigitals imbricate, keeled and triangular, subdigital lamellae of fourth finger 19, with distal margin slightly tridentate, claws long and slender. Tail short and robust, slightly thickened at the base and somewhat depressed. The rest is thick and rounded distally. Tail 0.75 times body length. Dorsal and lateral caudal scales tend to be irregular, rectangular, with interstitial granules and imbricate; wider than long, rugose and slightly imbricate on middle third of tail. Ventral caudal scales triangular on middle third of tail, but then are rectangular and strongly imbricate, longer than wider. Autotomic region with 12 scales on dorsal and lateral tail, and eight ventral scales. Coloration. The holotype has a dark red head and dorsal body color. Each side of the temporal region and body has sky blue scales that reach laterally to the tail. Ventrally there is a heavily variegated coloration, more intense on the lateral side and throat, ventral side color yellow with sandy brown spots, a pattern repeated on fore and hind limbs, and until the end of tail. Dorsal tail dark orange. Throat predominantly yellow, with sky blue scales and some red scales. Variation in morphological measurements and scaling. Variations based on four specimens , two males and two females , collected from the same site as the holotype , are presented in Table 1 . The females present a sandy brown colored head, similar to the sand on which they live. On the dorsal neck are two medium black spots which are in parallel along to the dorsal body, where they become larger and reach to the first part of the tail. Scapular area shows a short black spot subsequently followed by a white spot, a pattern which is along the dorso-thoracic region. Ventrally there is a slightly variegated pattern, more intense on the throat, ventral side color white with light gray spots, a pattern repeated on fore and hind limbs, and until the end of the tail. Female has dorsal scales well defined, not fragmented, circumorbital semicircles well-defined, large, and unfragmented subocular, parietals large, pentagonal, and well-defined. Differences are mainly in the form of interparietal, which in both females is hexagonal, while in the males it is irregular. Variation in the number and form of the scales: temporals eight between postocular and anterior margin of ear, 13 lorilabials, without a row of small scales between the subocular and lorilabials, eight supralabials, middorsal scales from occiput to point even with anterior margin of thigh 88. Elbow scales semitriangular and wider than long, but lightly keeled. The tail has a spotted pattern. Forelimb with small dark spots, and hindlimbs variegated with black and dark brown spots. Fig. 3. Dorsal (A) , ventral (B) , and lateral (C) views of the head of holotype HP20CBT. Fig. 4. Current (star) and potential (in gray) distributions of Liolaemus basadrei in the Jorge Basadre Province, Tacna, Peru, obtained from the MAxEnt algorithms. The dorsal area of the female is light brown or pinkish, and the head has dark brown and gray spots with an irregular shape and order. Lateral area of the head with dark brown spots that cross the muzzle transversely. Back of neck and body of the same color as the head, with large brown spots, arranged two on each side, bordered by a row of small white scales, a pattern that is repeated throughout the entire body. Paravertebral region with small brown spots, while in the lumbar area a greater number of white scales are observed. Along the tail, the dorsal pattern is lost and dark brown spots are observed in an irregular manner and shape, both dorsally and laterally. Forelimb and hindlimb with light brown spots irregular in shape and arrangement. Lateral area of the neck and body white, accompanied by irregular dark spots. Gular area with gray bands directed towards the mid-ventral area. Chest with small and very faint gray spots, white or slightly pink belly, ventral area of the fore and hind limbs without spots. Ventral area of the tail white or slightly pink. Ecology. The knowledge of this species is very poor. Apparently, its distribution is restricted to the Ephedra americana and Poissonia sp. desert scrub formation of the northern Tacna Region , collected in the Locumba valley, 64.5 km north of Tacna ( 17°45’21”S ; 70°45’51”W ) ( Fig. 4 ). Their activity was noted in the morning and afternoon, and this species thermoregulates at midday by seeking shade under rocks, cacti, or bushes. Reproductive phenology, as well as diet and distribution, are unknown. The new species shares its habitat with a species of Microlophus , currently under description, of similar size and mass, and the two species have been observed utilizing the same cacti as refugia ( Fig. 4 ). While there are other localities in southern Peru where Liolaemus and Microlophus can be observed in close proximity, elsewhere the Microlophus is of larger size and mass than the Liolaemus . The new species is the largest and most robust known species of the L. reichei clade and also the only one known to be associated with cacti. It is possible that the large size of the new species reflects its evolution in a resource-rich environment relative to the other species that are typically found in absolute desert areas with extremely sparse vegetation. The cacti likely provide food, water, refuge, and a reduced cost of thermoregulation. Examination of hawk and owl pellets from the Locumba Valley has yielded evidence that both species of lizards are important elements of the local trophic web (Valladares et al. 2021). Fig. 5. Terra typica of Liolaemus basadrei . Valle de Locumba, 897 m, Jorge Basadre Province, Region Tacna, Perú. The ecological niche modeling yielded an AUC of 0.988, indicating a high level of statistical confidence. The most informative variables for the current ecological niche of L. basadrei sp. nov. were physiography, the annual average temperature, and the type of life zone, followed by the type of climate, precipitation, and slope ( Table 3 ). The remainder of the variables had little intervention in the model according to the Jackknife test. The area of the ecological niche of L. basadrei sp. nov. is only 79.76 km 2 , with distribution exclusively in the Jorge Basadre and Tacna provinces, specifically in the districts of Locumba and Inclan, respectively, with a predicted altitudinal range of 650 to 1,125 m asl ( Fig. 4 ). Conservation status. According to the CPI variables considered by Cofré and Marquet (1999) , Liolaemus basadrei sp. nov. is a species that inhabits only a single ecoregion (absolute desert), with an extreme specialization: known range does not exceed 100 km 2 , with an abundance of 7 individuals/km 2 ; inhabits only southern Peru ; presents a low taxonomic singularity ( Liolaemus have around 300 species); this species is large, considering both the generic and specific level of the L. reichei clade (see Table 2 ); and it has anthropogenic pressure, because it lives near an interstate highway and agricultural areas, its habitat area includes high voltage towers, and its distribution is not within any protected wild areas. All the variables analyzed here indicate that L. basadrei is a species that should be considered as Endangered based on the CPI approach. Regarding the IUCN Red List criteria for evaluating whether a taxon belongs in a “threatened” category (IUCN 2012, 2019), we estimate the area of occupancy of L. basadrei to be less than 10 km 2 in a single location with ongoing threats to the extent and quality of its habitat, and we estimate its population size to be fewer than 250 mature individuals. Thus, we recommend the category of Critically Endangered B2ab(iii); C2a(ii). We have sampled localities broadly throughout southern Peru and northern Chile for more than 20 years, and we are confident that L. basadrei is restricted to an extremely small geographic area. Over the course of a year, we visited each of the areas identified as potentially suitable habitat in Fig. 4 and found the species only in the area which includes the type locality. As summarized in Table 4 , all species of the L. reichei clade assessed to date by the IUCN are categorized as either Endangered (four species) or Vulnerable (one species), while five species of the clade remain to be assessed. Etymology. We dedicate this species to Jorge Basadre Grohmann (1903–1980), a distinguished Peruvian historian and native of Tacna who wrote important works on the culture and history of Peru . Currently the National University of Tacna bears his name, as does one of the regional provinces of southern Peru .