Phymaturus Patagonicus Research Articles

Evidence of body size and shape stasis driven by selection in Patagonian lizards of the Phymaturus patagonicus clade (Squamata: Liolaemini)

During the speciation process sibling lineages accumulate differences in time (e.g. genetic, morphological, and/or ecological). Phenotypic traits such as size or shape, however, could experience rapid changes or show stasis depending on their role in survival and reproduction. The clade Phymaturus patagonicus includes 26 species characterized by a conservative morphology, and all inhabit rock crevice microhabitats in arid environments. In this study we quantify levels of morphological divergence (size and shape) among the multiple species relative to interspecific molecular divergence, and show that most species have not diverged significantly in size and/or shape to permit unambiguous species diagnosis with morphological data alone. The influence of stabilizing selection for an adaptive optimum in body size and head shape was detected for 13 of the 16 variables analyzed in an Ornstein-Uhlenbeck model. The strict dependence of these species to rock-crevice microenvironments likely explains the observed morphological stasis across the many species of the Phymaturus patagonicus group.

Multiple Sex Chromosome System and Robertsonian Rearrangements Involved in the Chromosome Evolution of thePhymaturus pallumagroup (Iguania: Liolaemidae)

Abstract The Liolaemid genus Phymaturus is a clade of saxicolous lizards with 44 species recognized, grouped in the Phymaturus palluma and the Phymaturus patagonicus groups. The chromosome data about this genus are extremely scarce; however, unpublished evidence suggests a great karyotypic diversity, mainly in the P. palluma group. In this work, we describe the karyotypes of six species of the P. palluma group (one of them unnamed) and report a multiple chromosome sex determination system with heterogametic males (X1X1X2X2 / X1X2Y). This sex-system represents a putative synapomorphy for the group. In accordance with the published literature and data obtained in this study, we report a wide variability for the diploid number of the P. palluma group (2N = 26 to 36) but same autosomic fundamental number in all the species of the clade (FNa = 32). Such variation is a consequence of different numbers of telocentric macroautosome pairs among karyotypes (2 to 10), suggesting chromosomal evolution of the group, d...

A new lizard species of the Phymaturus patagonicus group (Squamata: Liolaemini) from northern Patagonia, Neuquén, Argentina

The integrative taxonomy framework allows developing robust hypotheses of species limits based on the integration of results from different data sets and analytical methods. In this work, we test a candidate species hypothesis previously suggested based on molecular data, with geometric and traditional morphometrics analyses (multivariate and univariate). This new lizard species is part of the Phymaturus patagonicus group (payuniae clade) that is distributed in Neuquén and Mendoza provinces (Argentina). Our results showed that Phymaturus rahuensis sp. nov. differs from the other species of the payuniae clade by a higher number of midbody scales, and fewer supralabials scales, finger lamellae and toe lamellae. Also, its multidimensional spaces, both based on continuous lineal variables and geometric morphometrics (shape) characters, do not overlap with those of the other species in this clade. The results of the morphometric and geometric morphometric analyses presented here, coupled with previously published molecular data, represent three independent lines of evidence that support the diagnosis of this new taxon.

A new lizard of the Phymaturus genus (Squamata: Liolaemidae) from Sierra Grande, northeastern Patagonia, Argentina.

A new species of lizard of the saxicolous and viviparous genus Phymaturus from Patagonia is described. The new species is a member of the Phymaturus patagonicus species group distributed on volcanic plateaus, mountains or rocky outcrops of southern Argentina. Phymaturus yachanana sp. nov. differs from the other members of the patagonicus group by a dorsal pattern of small and medium-sized white spots on a brown background, the number of scales around the midbody, genetic differences in mitochondrial and nuclear markers, and allopatric geographic distribution in an isolated group of hills. As other species of the group, the new species is viviparous and herbivorous.

A new species of Phymaturus of the patagonicus clade (Squamata, Liolaemidae) from isolated plateau of southwestern Rio Negro Province, Argentina

A new Phymaturus species called Phymaturus sinervoi, is described in the present study. The new species is a member ofthe “Phymaturus patagonicus” group from Patagonia. It lives at about 1100 m of altitude in a volcanic rocky habitat nearto Cari Laufquen plateau, in the southern-central steppe of Rio Negro Province, Argentina. The new species and the neigh-bouring related species of the genus from the “patagonicus” group are morphologically compared, and its distribution and natural history are pointed out.

Two new mountain lizard species of the Phymaturus genus (Squamata: Iguania) from northwestern Patagonia, Argentina

Two new species of lizards of the saxicolous and viviparous genus Phymaturus from Patagonia are described. The new species are members of the Phymaturus patagonicus species group distributed only in volcanic plateaus and mountains of southern Argentina. Phymaturus sitesi sp. nov. differs from all other members of the patagonicus group in its unique dorsal pattern of small white spots on a light-gray to brown-gray background and allopatric geographical distribution. Absence of sexual dichromatism differentiated Phymaturus sitesi sp. nov. from P. payuniae, P. zapalensis, and P. delheyi n. sp. , and the midbody scales count differentiated from the P. delheyi sp. nov. and P. nevadoi (with some overlap). Also Phymaturus sitesi sp. nov. presents lower count in the ventral scales than in P. delheyi sp. nov. Phymaturus delheyi sp. nov. can be distinguished from other species of the patagonicus group by unique dorsal pattern of medium size white spots on a dark-brown background and allopatric distribution. The presence of sexual dichromatism differentiates Phymaturus delheyi sp. nov. from P. sitesi sp. nov. and P. nevadoi. Scales around midbody differentiated Phymaturus delheyi sp. nov. from P. payuniae and P. sitesi sp. nov. Also ventral scale count differentiated Phymaturus delheyi sp. nov. from P. sitesi sp. nov. and P. nevadoi (with some overlap).

Susceptibility of lizards to predation under two levels of vegetative cover

The risk of increased predation is a potential cost for habitat specialists, when dispersing through non-habitat matrix. We hypothesized that dispersal success of lizards is limited by the loss of vegetative cover, as occurs with overgrazing, due to increased susceptibility to predation. We analyzed the movement behavior of the saxicolous lizards ( Liolaemus elongatus and Phymaturus patagonicus) in the Patagonian steppe using a habitat generalist ( Liolaemus bibroni) as a control species. We compared the proportion of stops on bare ground during movement in two experimental enclosures with different levels of vegetative cover. Both specialists and generalists stopped more frequently on bare ground when there was less vegetative cover, and specialists stopped more frequently than generalists on bare ground. We found no significant difference in the time it took specialists to reach the end of the enclosure in the two different levels of vegetative cover. Additionally we compared the time to capture by a human predator under the two levels of vegetative cover. All species were captured more quickly when there was less vegetative cover and we found a tendency towards shorter capture times in specialists than in generalists. Our results suggest that saxicolous lizards are more susceptible to predation with less vegetative cover.

A new fragment for the understanding of the puzzling evolutive process of the Phymaturus genus: a new species of the patagonicus group from Patagonia, Argentina (Reptilia: Iguania: Liolaemidae)

A new species, Phymaturus sp. nov. is described as a new member of the Phymaturus patagonicus group of patagonian geographic distribution. It is distinguished by having flat imbricate superciliaries rather than rectangular and non-overlapping, and slightly spiny caudal scales in verticilles. Additionally, the subocular scale is fragmented and separated from the supralabials by two rows of lorilabials (as in most species of the palluma group). The species may be distinguished from other members of the patagonicus group by having metric and meristic differences, as well as a peculiar color pattern characterized by a notorious polychromatism. It lives at about 1000 m of altitude in rocky outcrops near Comallo, in southwestern Rio Negro Province, Argentina. The new species and the closely related species of the patagonicus group are morphologically compared, and its distribution and natural history are described.

When starvation challenges the tradition of niche conservatism: On a new speciesof the saxicolous genus Phymaturus from Patagonia Argentina withpseudoarboreal foraging behaviour (Iguania, Liolaemidae)

The genus Phymaturus is known on the basis of almost twenty species with clear tendency to conserve saxicolous or terrestrial, and herbivorous niche. In this work, we present the description of a remarkable new Phymaturus species, Phymaturus agilis, with the peculiar ability to climb on large shrubs to feed on fresh flowers and fruits. This new species is a member of the Phymaturus patagonicus clade, restricted to Patagonia Argentina. Phymaturus agilis occurs at about 1100m of elevation in a volcanic rocky plateau close to Ingeniero Jacobacci, in the south western area of Rio Negro Province, Argentina. Comparative analyses conducted on morphological and coloration traits revealed substantial differences from Phymaturus spectabilis, the only Phymaturus species living in sympatry with P. agilis. Individuals of both species had recently been recognized as members of a single taxon with broad phenotypic variation.

A new species of Phymaturus from rocky outcrops in the central steppe of Rio Negro province, Patagonia Argentina (Reptilia: Iguania: Liolaemidae)

A new Phymaturus species called Phymaturus ceii, in the honour of the late Professor José Miguel Cei, is described in the present study. The new species is a member of the “Phymaturus patagonicus” group from Patagonia. It lives at about 1200 m of altitude in a volcanic rocky habitat near to El Cuy plateau, in the central steppe of Rio Negro province, Argentina. The new species and the closely related P. patagonicus are morphologically compared, and its distribution and natural history are pointed out.

Age and growth of the Patagonian lizard Phymaturus patagonicus

AbstractThe growth dynamics of Phymaturus patagonicus, a diurnal, herbivorous and viviparous lizard from the Argentinean Patagonian steppe, was studied using eight juveniles (two born in the laboratory), 11 adult females and eight adult males. Histological cross sections of femoral bones were analysed to determine if individuals show osseous growth marks and if these marks provide useful age estimates. Individual ages were assessed after estimating the reabsorbed rings in relation to snout-vent length. There was a strong relationship between body length and estimated age, modelled by a sigmoidal curve. Sexual maturity was found to be reached at seven years in females and nine in males and the maximum life span was estimated to be 16 years. No difference in body length was observed between the same-age females and males. We postulate that severe environments such as the north Patagonian steppe play a significant role in the selection of not only modes of reproduction but also delayed maturity and prolonged reproductive cycles, a combination that results in low fecundity.

Taxonomic Studies of the Genus Phymaturus (Iguania: Liolaemidae): Redescription of Phymaturus patagonicus Koslowsky 1898, and Revalidation and Redescription of Phymaturus spurcus Barbour 1921

Phymaturus spurcus was described by Barbour in 1921. In 1931, Burt and Burt placed this species in the synonymy of Phymaturus patagonicus based on their comparison of one paratype of P. spurcus with one specimen of P. patagonicus. Additionally, Burt and Burt considered P. patagonicus a subspecies of Phymaturus palluma. Although some subsequent authors accepted the synonymy of P. patagonicus with P. palluma, the synonymy of P. spurcus with P. patagonicus has gone unquestioned. We examined the type series of P. patagonicus and P. spurcus, as well as new material collected from the type localities of both species. Based on 47 morphological characters of squamation, gular and nuchal folds, precloacal pores, and morphometric data, we conclude that P. spurcus is a valid species, distinct from P. patagonicus and all other Phymaturus. We agree with Cei and Castro's study in 1973 that the population located west of Dolavon, Chubut Province, Argentina, is P. patagonicus of Koslowsky' study in 1898 Because in the original description Koslowsky failed to designate an holotype, we designate Museo La Plata S-778 as the lectotype of P. patagonicus and restrict its type locality to 40 km west of Dolavon, Chubut Province, Argentina. We provide a redescription of P. patagonicus Koslowsky and a redescription of P. spurcus based on the type series of Barbour's study in 1921, with additional data on intraspecific variation in both species.

Field, selected body temperature and thermal tolerance of the syntopic lizards Phymaturus patagonicus and Liolaemus elongatus (Iguania: Liolaemidae)

Liolaemus elongatus and Phymaturus patagonicus are viviparous lizards syntopic in the rock promontories of the arid Patagonia exposed to seasonal extremes, short activity seasons and long submergence periods. L. elongatus is a slender lizard mainly heliothermic, which occupies a variety of microhabitats and has a widespread distribution. P. patagonicus, instead is a tigmotherm and flat body lizard which lives only in the clefts of rock promontories and has a restricted distribution to the north west Patagonia. In the present work, the field and selected body temperature and their thermal tolerance are explored. L. elongatus shows a higher plasticity than P. patagonicus in the use of the microhabitats, the heat acquisition, and the activity timetables. However both species show low field and selected body temperature compared to most lizards (30 °C). These results reinforce the hypothesis between reproduction and body temperature postulated by previous works on reproductive biology of both species.

Prolonged Cycles as a Common Reproductive Pattern in Viviparous Lizards from Patagonia, Argentina: Reproductive Cycle of Phymaturus patagonicus

Previous studies have shown both prolonged and plastic cycles in viviparous females of the genus Liolaemus (Iguania: Liolaemidae) from the cold temperate climate of Patagonia. Males have shown interspecific variation in the duration of the breeding season, ranging from continuous to annual. Both cycles are far different from the reproductive cycles previously described for lizards from temperate climates. I examined maximum juvenile size, growth, sexual dimorphism, male and female reproductive cycles, and litter size of viviparous Phymaturus patagonica (Iguania: Liolaemidae), a species restricted to rock promontories in the Patagonian steppe. The reproductive cycle in males is annual with spermatogenesis beginning in December and peaking in early spring of the next year. Spermatozoa are stored in the epididymides for at least two months until mid-January. In contrast, females have a biennial cycle. Thus, prolonged female cycles and large interspecific differences in male cycles characterize viviparous lizards from Patagonia.