Cristian Simón Abdala

Chasing the Patagonian sun: comparative thermal biology of Liolaemus lizards

The importance of the thermal environment for ectotherms and its relationship with thermal physiology and ecology is widely recognized. Several models have been proposed to explain the evolution of the thermal biology of ectotherms, but experimental studies have provided mixed support. Lizards from the Liolaemus goetschi group can be found along a wide latitudinal range across Argentina. The group is monophyletic and widely distributed, and therefore provides excellent opportunities to study the evolution of thermal biology. We studied thermal variables of 13 species of the L. goetschi group, in order to answer three questions. First, are aspects of the thermal biology of the L. goetschi group modelled by the environment or are they evolutionarily conservative? Second, have thermal characteristics of these animals co-evolved? And third, how do the patterns of co-evolution observed within the L. goetschi group compare to those in a taxonomically wider selection of species of Liolaemus? We collected data on 13 focal species and used species information of Liolaemus lizards available in the literature and additional data obtained by the authors. We tackled these questions using both conventional and phylogenetically based analyses. Our results show that lizards from the L. goetschi group and the genus Liolaemus in general vary in critical thermal minimum in relation to mean air temperature, and particularly the L. goetschi group shows that air temperature is associated with critical thermal range, as well as with body temperature. Although the effect of phylogeny cannot be ignored, our results indicate that these thermal biology aspects are modelled by cold environments of Patagonia, while other aspects (preferred body temperature and critical thermal maximum) are more conservative. We found evidence of co-evolutionary patterns between critical thermal minimum and preferred body temperature at both phylogenetic scales (the L. goetschi group and the extended sample of 68 Liolaemus species).

Running in cold weather: morphology, thermal biology, and performance in the southernmost lizard clade in the world (Liolaemus lineomaculatus section: Liolaemini: Iguania)

The integration or coadaptation of morphological, physiological, and behavioral traits is represented by whole-organism performance traits such as locomotion or bite force. Additionally, maximum sprint speed is a good indicator of whole-organism performance capacity as variation in sprinting ability can affect survival. We studied thermal biology, morphology, and locomotor performance in a clade of Liolaemus lizards that occurs in the Patagonian steppe and plateaus, a type of habitat characterized by its harsh cold climate. Liolaemus of the lineomaculatus section display a complex mixture of conservative and flexible traits. The phylogenetically informed analyses of these ten Liolaemus species show little coevolution of their thermal traits (only preferred and optimum temperatures were correlated). With regard to performance, maximum speed was positively correlated with optimum temperature. Body size and morphology influenced locomotor performance. Hindlimbs are key for maximal speed, but forelimb length was a better predictor for sustained speed (i.e. average speed over a total distance of 1.2 m). Finally, sustained speed differed among species with different diets, with herbivores running on average faster over a long distance than omnivores.

Two New Species of Liolaemus (Iguania: Liolaemidae) from the Puna of Northwestern Argentina

Abstract We describe two new species of Liolaemus belonging to the montanus series. The new species are closely related to L. dorbignyi, but are disjunctly distributed with respect to this taxon. Both new species exhibit unique color patterns, which, along with differences in squamation, differentiate the two new taxa from the other species in the series. Both new species are saxicolous and inhabit rocky hills in the Puna regions of northwestern Argentina. One occurs in the Cerro de la Virgen, Nevados de Cachi and Nevados de Palermo of Salta Province. The other is known only from its type locality in the Cerro El Pichao of Tucumán Province.

DESCRIPTION OF A NEW PATAGONIAN LIZARD SPECIES OF THE LIOLAEMUS SILVANAE GROUP (IGUANIA: LIOLAEMIDAE)

Abstract A new specie of the Liolaemus genus is described in the present work, it was collected in the north-west of Santa Cruz Province, Argentina, at 1485 m. This new lizard belongs to the silvanae group, previously described as Vilcunia genus, characterized by the absence of precloacal pores in males, the presence of dorsal tridentate scales, lateral keeled nuchal scales overlap and postfemoral scales subimbricated. This Patagonian specie has a small size, with a squat look and shows a dorsal coloration pattern with outstanding dorsal-lateral bands, these bands can be of different colors, such as yellow, orange, brown or grey. The individuals of this specie are melanics in the ventral part of the body. This new specie lives in a place with extreme climatic conditions, low temperatures and with a cloudy sky most of the time. These are insectivorous and viviparous lizards, whose phylogenetic relationship with other members of the group are still unknown.

Two New Species of Liolaemus (Iguania: Liolaemidae) of Central West Argentina

Abstract We describe two new species of lizards of the genus Liolaemus belonging to the chiliensis group, one found in southwestern Catamarca, and the other in central western Argentina, in Mendoza, San Juan and Catamarca provinces. The species from southwestern Catamarca has morphological characteristics that may relate it to the species of the capillitas group, a northern clade of the elongatus group, whereas the other species has characters that relate it to the southern clade of the elongatus group. Both species exhibit diagnoistic character states in their maximum snout-vent length, squamation, and dorsal and ventral colors, which differentiate them from the other species of the chiliensis group.

Climate, geographic distribution and Viviparity in Liolaemus (Reptilia; Squamata) species: when hypotheses need to be tested

(1) Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA), CONICET-UNCOMA, Quintral 1250, Bariloche, 8400 Río Negro, Argentina. (2) Department of Biology, 212 Clarkson Science Center, MRC 5805, 8 Clarkson Avenue, Clarkson University, NY. Estados Unidos. (3) Facultad de Ciencias Naturales e I. M. Lillo (UNT), CONICET-Instituto de Herpetología (FML), Tucumán, Argentina. Miguel Lillo 205, 4000, San Miguel de Tucumán, Argentina.

From the far reaches of Patagonia: new phylogenetic analyses and description of two new species of the Liolaemus fitzingerii clade (Iguania: Liolaemidae)

Within the Liolaemus boulengeri group or ‘patch’ group, there is a monophyletic clade named Liolaemus fitzingerii group.This clade is composed of large Liolaemus individuals, mostly psammophilus, oviparous and mainly insectivorous, dis-tributed from central Rio Negro and Neuquen to the south of Santa Cruz in Argentine Patagonia. We make a taxonomicand phylogenetic revision of the L. fitzingerii clade, describe two new species of the group, compare these results withphylogenetic hypotheses from the literature, and discuss the geographic distribution of species of the L. fitzingerii clade.The new species described here inhabit central and central-eastern Chubut Province, Argentina. These new species areeasily distinguished from the other species of the L. fitzingerii group by a combination of morphological characters. Thephylogenetic analyses support the description of these new species, because they are not closely related to the species withwhich they were previously confused. According to a new phylogenetic analysis of the L. fitzingerii clade, one of the newspecies, L. camarones sp. nov., has a relatively basal position within the group, whereas the other new species, L. shehuen sp. nov., is sister taxon of L. chehuachekenk. With these two new species, the L. fitzingerii clade is now composed of nine species, all of which are distributed in Argentine Patagonia.

Effect of body mass and melanism on heat balance in Liolaemus lizards of the goetschi clade

ABSTRACT The body temperature of ectotherms depends on the environmental temperatures and behavioral adjustments, but morphology may also have an effect. For example, in colder environments, animals tend to be larger and to show higher thermal inertia, as proposed by Bergmanns rule and the heat balance hypothesis (HBH). Additionally, dark coloration increases solar radiation absorption and should accelerate heat gain (thermal melanism hypothesis, TMH). We tested Bergmanns rule, the HBH and the TMH within the Liolaemus goetschi lizard clade, which shows variability in body size and melanic coloration. We measured heating and cooling rates of live and euthanized animals, and tested how morphology and color affect these rates. Live organisms show less variable and faster heating rates compared with cooling rates, suggesting behavioral and/or physiological adjustments. Our results support Bergmanns rule and the HBH, as larger species show slower heating and cooling rates. However, we did not find a clear pattern to support the TMH. The influence of dorsal melanism on heating by radiation was masked by the body size effect in live animals, and results from euthanized individuals also showed no clear effects of melanism on heating rates. Comparison among three groups of live individuals with different degrees of melanism did not clarify the influence of melanism on heating rates. However, when euthanized animals from the same three groups were compared, we observed that darker euthanized animals actually heat faster than lighter ones, favoring the TMH. Although unresolved aspects remain, body size and coloration influenced heat exchange, suggesting complex thermoregulatory strategies in these lizards, probably regulated through physiology and behavior, which may allow these small lizards to inhabit harsh weather environments. Summary: Body size and coloration influence heat exchange in Liolaemus lizards, suggesting complex thermoregulatory strategies that are probably regulated through physiology and behavior, which may enable these small lizards to inhabit the harsh Patagonian environment.

Multiple lines of evidence show that Phymaturus agilis Scolaro, Ibargüengoytía & Pincheira-Donoso, 2008 is a junior synonym of Phymaturus spectabilis Lobo & Quinteros, 2005

Lobo and Quinteros (2005) described Phymaturus spectabilis from Rio Negro Province, Argentina. The species was characterized most notably by having a brown background with a more-or-less bilaterally symmetrical pattern of bold, light tan markings, some enclosing small brown spots, on the head, limbs, body, and tail. In 2008, Scolaro et al. described P. agilis from a locality 22 km south of the type locality of P. spectabilis. It was reported to differ from P. spectabilis in its nearly uniform brown color and certain morphometric and meristic characteristics. In 2009 we collected, at the type locality of P. agilis, five adults (both sexes) with the bold pattern of P. spectabilis, and five adults (both sexes) with the uniform color of P. agilis. Subsequently, one of the females with the P. spectabilis pattern gave birth to two individuals, one of which had the pattern of P. agilis, the other with the pattern of P. spectabilis. Our analyses of specimens assignable to P. agilis and P. spectabilis detected no significant differences between individuals with the two patterns for nine morphological variables (including those used to diagnose P. agilis), with overlap in the ranges of the variables for both patterns. We therefore conclude that P. agilis is a junior synonym of P. spectabilis.

A New Species of Liolaemus (Iguania: Liolaemidae) of the alticolor-bibronii Group from Northern Chile

Abstract We describe a new slender species of Liolaemus of the L. alticolor-bibronii group of the subgenus Liolaemus. The new species is phenetically and biogeographically close to L. alticolor, L. paulinae, and L. puna but presents a combination of character states that differentiates it from all other species of Liolaemus. The new taxon is the first species of subgenus Liolaemus sensu stricto recorded as having supernumerary pores. The new species inhabits places where Parastrephia lucida is the predominant flora and is distributed in areas close to Putre, in the Arica y Parinacota region, northern Chile. Data on its biology, complete distribution, and conservation status are lacking.