A new species of Stenocercus (Squamata, Iguania) from central-western Brazil with a key to Brazilian Stenocercus

A new species of Stenocercus from centralwestern Brazil differs from other Stenocercus by the following combination of characters: head and body scales strongly keeled, posthumeral and postfemoral mite pockets absent, nostrils laterally oriented, supraciliary scales not enlarged or projected, and caudal fracture planes absent. Morphologically, the new species more closely resembles S. prionotus and S. caducus. The latter species has been reported in Brazil based on misidentified specimens from Mato Grosso that correspond to the new species described herein. However, it is very likely that S. caducus occurs in Brazil because it has been reported from geographically close areas. Therefore, I recognize seven species of Stenocercus from Brazil and provide a dichotomous key to assist in the identification of specimens

Phylogenetic systematics of South American lizards of the genus Stenocercus (Squamata: Iguania)

The South American iguanian lizard genus Stenocercus includes 58 species occurring mostly in the Andes and adjacent lowland areas from northern Venezuela and Colombia to central Argentina at elevations of 0--4000 m. Limited taxon or character sampling have characterized all previous phylogenetic analyses of Stenocercus, which has repeatedly been proposed as sister taxon to the Tropidurus Group. In this study, I use molecular and morphological data to (1) infer the phylogenetic relationships among most species of Stenocercus, (2) perform explicit statistical tests of previous phylogenetic hypotheses, and (3) infer the ancestral distribution of Stenocercus. Using parsimony and Bayesian analyses, monophyly of this genus is strongly supported with a dataset of 32 species of Stenocercus, 12 outgroup taxa, and 1641 bp of mtDNA. Molecular data also are used to analyze evolutionary relationships within Stenocercus with a Bayesian approach based on mixture models, which accommodate variability in the parameters of the rate matrix across sites. Morphological data were obtained from 55 species of Stenocercus and one outgroup taxon; polymorphic and continuous morphological characters were coded using step matrices with frequency parsimony and gap-weighting methods, respectively. Parsimony and Bayesian analyses were performed with a combined dataset of 55 ingroup taxa, one outgroup taxon, and 1764 characters. All analyses support a basal split of Stenocercus into two clades. When all 55 ingroup taxa are included, these clades are composed of 26 (clade A) and 29 (clade B) species. In general, species in clade A have small scales and granular scales on the posterior surface of thighs, whereas species in clade B have large scales and non-granular, imbricate scales on posterior surface of thighs. Clade A is restricted to the central Andes except for a few species occurring in the northern Andes in Ecuador and Colombia. Clade B is more widespread and includes species occurring in the northern, central, and southern Andes, as well as species in the Amazon Basin and lowlands in southeastern South America. A dispersal-vicariance analysis suggests that the most recent common ancestor of species of Stenocercus occurred in the central Andes. Four new species of Stenocercus are described from the northern Andes of Colombia, southern Andes of Ecuador, northern and central Andes of Peru, and Cerrado forest in Brazil. In addition, S.torquatus is resurrected and S.variabilis is redescribed

Reptilia, Squamata, Tropiduridae, <i>Stenocercus sinesaccus</i> Torres–Carvajal, 2005: Distribution extension

The present study reports the easternmost known record for the tropidurid lizard Stenocercussinesaccus Torres–Carvajal, 2005, at Floresta Nacional de Silvânia, state of Goiás, Brazil, in a transition areabetween cerrado sensu strictu and gallery fores

The cranial osteology of the iguanid lizard Stenocercus guentheri (Squamata: Iguanidae) and its postembryonic development

Thesis (M.A.)--University of Kansas, Ecology and Evolutionary Biology, 2001.In spite of the great diversity of iguanid lizards, detailed descriptions of their osteocrania and postembryonic development are rare. Herein, the adult cranial osteology of the iguanid lizard Stenocercus guentheri and its postembryonic development are described based on cleared and double-stained and dry skeletal specimens from a single Ecuadorian population. The amphikinetic skull of S. guentheri is short and elevated, and bears teeth on the premaxilla, maxillae, and pterygoids. Mandibular teeth are present on the dentaries. Males having wider skulls than females, no other sexual dimorphism in the cranial osteology was found. Ossification of the articular from Meckel's cartilage, and growth of the parietal (ossification and investment of the frontoparietal fontanelle), are the most significant ontogenetic changes of the splanchnocranium and dermatocranium, respectively. The ossification of the cartilage separating the bones of the braincase is the most relevant postembryonic ontogenetic event of the neurocranium. The number of teeth does not vary ontogenetically and replacement teeth are present throughout postembryonic life. This study includes a list of the osteocranial characters of Stenocercus that have been used in systematic studies·, as well as a discussion of functional morphology and kinesis

Presencia de Stenocercus azureus Müller 1880 (Squamata: Iguania) en la República Argentina

Localidades: República Argentina, Provincia de Corrientes: Departamento Ituzaingó: Estancia San Alonso, Reserva Natural del Iberá (28°19' 58.34"S; 57°28' 13.44"W - Fig. 1). Fecha de colección: 09 de diciembre de 2014. Colectores: Eduardo Etchepare, Dionel Aguiar y Soledad Palomas. Hembra adulta (Fig. 2, 3 y 4), longitud hocico-cloaca 79,7 mm; longitud total 219,7 mm, depositada en la Colección Herpetológica de la Universidad Nacional del Nordeste (UNNEC 13000). Departamento de Ituzaingó: Ruta Prov. 10 entre Playadito y Ruta Nac. 14 (27°53' 21.41"S- 55°55' 48.20"W): ejemplar adulto fotografiado por Julián M. Alonso (Fig. 5 y 6), sin voucher.Fil: Etchepare, Eduardo Gabriel. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Aguiar, Dionel. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Palomas Alaniz, Yanina Soledad. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Giraudo, Alejandro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Alonso, Julián. Administracion de Parques Nacionales; Argentin

Activity Patterns of Stenocercus iridescens in an Ecuadorian Coastal Agroecosystem: Is Temperature Important?

Circadian rhythms of Neotropical lizards have been poorly studied, which represents a problem when designing ecological studies or monitoring such species based on direct observations. In this work, 1000 m-long transects were established in an agroecosystem area of the Ecuadorian coast region to study the activity patterns of Stenocercus iridescens. The number of individuals (as a response variable) was correlated with local weather conditions: temperature, precipitation, and heliophany (duration of the solar brightness). We carried out the study in both dry and rainy seasons, and during different time ranges. The time range in which the transects were performed was the most important predictor, and the activity peak was established between 16:00 h and 18:00 h. Heliophany negatively affected lizard activity, but only on the days with higher heliophany during the dry season, whereas temperature was not a significant predictor. Our results suggest that in an area where temperature is relatively constant and the solar radiation is high, particularly during the dry season, the heliophany (an indirect measure of solar radiation) can affect ectotherm activity patterns more than temperature, particularly in open habitats such as agroecosystems

Repartición de recursos entre Microlophus occipitalis y Stenocercus puyango (Sauria: Tropiduridae) en el Parque Nacional Cerros de Amotape, Tumbes, Perú

Activity, microhabitat use, and diet are patterns commonly used to define the saurian community structure, because of differential exploitation allowing coexistence at the same time and place. We analyze resource partitioning between two sympatric saurian species, Stenocercus puyango and Microlophus occipitalis, in the transitional area of the Pacific Tropical Forest and the Dry Forest inside Cerros de Amotape National Park (PNCA) in Tumbes, northwestern of Peru. Microlophus occipitalis and S. puyango both showed a unimodal activity pattern with higher activity around 13:00 h, with a mean body temperature of 34.83 °C and 32.17 °C respectively, observing a significant relationship between body and environmental (air and substrate) temperatures. Rocks and tree trunks were the most frequent microhabitats used by M. occipitalis while S. puyango were registered more frequently over leaf litter. The diets of both tropidurids were composed by arthropods, ants, and insect larvae mainly. Similarities in activity times (temporal niche) and diet (trophic niche) should be related to phylogenetic relationship and environmental characteristics of PNCA (seasonality, vegetal composition) meanwhile differences in space use and microhabitat thermal quality will be related to thermal quality in the area.Los horarios de actividad, el uso de microhábitat y dieta, son patrones comúnmente utilizados para dilucidar la estructura de una comunidad de saurios, ya que estos hacen un uso diferenciado de los recursos que explotan, lo que les permite coexistir de forma adecuada en el mismo tiempo y lugar. Analizamos la repartición de recursos entre dos especies simpátridas de saurios, Stenocercus puyango y Microlophus occipitalis, en la zona transicional entre el Bosque Tropical del Pacifico y el Bosque Seco en el Parque Nacional Cerros de Amotape (PNCA), departamento de Tumbes, analizando el solapamiento del nicho espacial, temporal y trófico entre ambas especies, incluyendo algunos aspectos de sus ecologías termales. Microlophus occipitalis y S. puyango presentaron un patrón de actividad unimodal con un pico de actividad hacia las 13:00 horas y una temperatura corporal promedio de 34.83 °C y 32.17 °C, respectivamente, registrándose una relación significativa entre la temperatura corporal y las temperaturas ambientales (aire y suelo). Los microhábitats más utilizados por M. occipitalis fueron los troncos caídos y rocas, mientras que S. puyango fue registrado principalmente sobre hojarasca. La dieta de ambos tropidúridos estuvo compuesta por artrópodos, principalmente hormigas y larvas de insectos. Las similitudes encontradas tanto en los horarios de actividad (nicho temporal) como en la dieta (nicho trófico), estarían asociadas a su parentesco filogenético y a características ambientales propias dentro del PNCA (estacionalidad, composición vegetal), mientras que las diferencias en el uso del espacio y temperaturas corporales entre ambas especies estarían relacionada a la calidad térmica de los microhábitats presentes en el área

Living in a cold tropical mountain: do the microhabitat use and activity pattern change with elevation in the high-Andean lizard Stenocercus trachycephalus (Squamata: Tropiduridae)?

The high mountain environment is a tough habitat that imposes many challenges to reptiles. As temperature decreases with altitude and has a dramatic variation throughout the day in the tropical mountains, ectotherms must cope with these harsh conditions. We studied the use of microhabitat and activity patterns of Stenocercus trachycephalus in the eastern Andes mountain range of Colombia. Three localities were sampled across the wide altitudinal distribution of this lizard species, in a range from 2,670 to 3,950 m a.s.l. The initial hypothesis was that these natural history traits would change with altitude but instead, we found that they remained roughly consistent, showing the great plasticity of this species. The results support that this lizard is a microhabitat-generalist using principally herb across the gradient, rarely shifting to specific plants or microhabitats such as rocks depending on availability. Regarding the activity pattern, this species was active throughout the day from 8:00 to 16:00 with a similar pattern along the gradient. Nevertheless, some differences were detected across localities. The activity pattern shifted from bimodal in the lower locality to unimodal in the higher ones. As expected, a correlation between temperature and activity patterns was found in one of the study sites. However, this was not the case for the lower and mid-elevation localities, where there was no correlation between these variables. The mid-elevation study site was the most interesting locality as the use of microhabitat relied virtually just on the herb stratum and the activity was constrained to the morning hours. These findings may be the result of the synergic effects of other ecological variables (weather variability, human impact, predation, population structure, or reproductive season). Our study gives the basis for a better understanding of how behavior (microhabitat choice and hours of activity) of ectotherms can help to counter thermal constraints in the neotropics when facing an altitudinal gradient. Further studies should focus on the thermal biology of this species, considering the influence of anthropic impact on these lizards’ populations

Stenocercus azureus

Listed as Least Concern on the basis that this species has a very wide range in southern South America. It is nonetheless rare throughout this range, and while it is not thought to be at immediate risk of extinction insufficient information exists on its population status, natural history or the impacts of threats from habitat loss. This lizard is known from the lowlands of southeastern South America. It occurs in the States of Parana, Rio Grande do Sul, and Sao Paulo in southern Brazil and in Uruguay; it has been collected between 150 and 250 m asl (Torres-Carvajal 2007). The species has also been reported for Corrientes and Misiones provinces, Argentina (A. Giraudo and E. Etchepare pers comm. 2014). It may also occur in Paraguay (P. Cacciali and N. Scott pers. comm. 2014). This species is found in Atlantic forest and Pampas grasslands. It is an egg laying species (Torres-Carvajal 2007).Fil: Cacciali Sosa, Pier. Universidad Técnica de Comercialización y Desarrollo; ParaguayFil: Kacoliris, Federico Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Montero, Ricardo. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pelegrin, Nicolas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Etchepare, Eduardo Gabriel. Universidad Tecnológica Nacional. Facultad Regional de Concordia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin