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

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

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

Reptilia, Squamata, Iguanidae, Stenocercus aculeatus: distribution extension and first record for Ecuador

Non

Gonatodes caudiscutatus (Günther, 1859) (Squamata: Sphaerodactylidae): distribution extension in Ecuador

Gonatodes caudiscutatus is currently known from the Pacific coast of Ecuador, the Galapagos Archipelago and Peru (all west of the Andes). Here we provide the first records of this species from the Upper Amazon Basin east of the Andes in Ecuador. We found no morphometric or meristic differences between populations east and west of the Andes except in the number of loreals (fewer on eastern populations), and in the number of supraciliary spines (more individuals with higher number of supraciliary spines on western populations)

A new species of Enyalioides (Iguanidae: Hoplocercinae) from southwestern Ecuador

We describe a new species of Enyalioides from lowland cloud forests in southwestern Ecuador. This represents the third species in the genus known to occur west of the Andes in South America; the other two species are E. heterolepis and E. oshaughnessyi. Among other characters, the new species can be distinguished from other members in the genus by having small, keeled, paravertebrals; a series of skin folds on the lateral aspects of body and neck; size-homogeneous scales on body and limbs; distinct caudal segments; and an extensive dark patch on the gular region of adult males. Morphological similarity suggests that the new species, which we call E. touzeti, is closely related to E. oshaughnessyi.Describimos una especie nueva de Enyalioides del bosque nublado al suroccidente de Ecuador. Esta representa la tercera especie de este género que habita al occidente de los Andes en América del Sur; las otras dos especies occidentales son E. heterolepis y E. oshaughnessyi. La especie nueva se diferencia de otras especies del género por tener, entre otras características, paravertebrales pequeñas y quilladas, pliegues dermales a los lados del cuello y cuerpo, escamas homogéneas en el cuerpo y extremidades, segmentos caudales visibles, y un parche oscuro que cubre gran parte de la región gular en machos. Semejanzas morfológicas sugieren que la especie nueva, a la cual llamamos E. touzeti, está cercanamente relacionada con E. oshaughnessyi

A new cryptic species of Anolis lizard from northwestern South America (Iguanidae, Dactyloinae)

A new species of Anolis lizard from the Andean slopes of southwestern Colombia and northwestern Ecuador, from between 1187 and 2353 m in elevation, is described. The new species can be distinguished from other Anolis in squamation, cranial osteology, hemipenial morphology, and nuclear and mitochondrial DNA. The new species is sister to Anolis aequatorialis, and it is suggested that previous records of A. aequatorialis in Colombia correspond to the new species described herein

Connectivity, population structure, and conservation of Ecuadorian green sea turtles

Studies of highly migratory species that increase our understanding of the dynamics of genetic diversity, migratory routes, and genetic connectivity are essential for informing conservation actions. Genetic data for green turtles Chelonia mydas from Ecuador have only been available from Galápagos Islands (GPS) rookeries, but not from foraging aggregations. Furthermore, green turtles from habitats associated with mainland Ecuador (Machalilla National Park; MNP) have not been sampled. To assess the genetic relationships between nesting and foraging aggregations from these 2 regions and other regional populations, the mitochondrial DNA (mtDNA) control region was sequenced from 133 turtles. Conventional FST (haplotype frequency) and ΦST (sequence-based) values were low and non-significant between Ecuadorian rookeries, suggesting high connectivity between these sites located ca. 1000 km apart. Mixed stock analysis (MSA) indicated a dominant (>94%) GPS-MNP contribution to both foraging grounds, with small and nearly negligible contributions from other rookeries in the region (e.g. Costa Rica and Mexico). While orphan haplotypes were not included in the MSA because their rookery of origin is not known, their close genetic relationships to Western and Central Pacific mtDNA clades suggests that a relatively large percentage of turtles at the combined foraging sites (>10%) have been involved in transoceanic migration events. The genetic links between GPS and MNP C. mydas nesting populations revealed by our study highlight the need to incorporate the nesting populations from coastal Ecuador in more comprehensive future conservation planning.Ministerio del Ambiente/[005-DRM-MA]//EcuadorMinisterio del Ambiente/[011-DRM-MA]//EcuadorParque Nacional Galápagos/[PC-20-14]//EcuadorUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM

Efecto del hierro en el crecimiento y acumulación de lípidos en la microalga colombiana Chlorella Vulgaris LAUN 0019

En este trabajo se evalúa el efecto del ión ferroso (Fe2+) sobre el crecimiento y acumulación de lípidos totales de la microalga Chlorella vulgaris. Se empleó medio Bristol estándar para su cultivo; la cinética de crecimiento se midió por conteo directo y la determinación de lípidos totales se realizó mediante extracción con Soxhlet. Se estudiaron cinco diferentes concentraciones de este ión, entre 2,16 μM y 50,0 μM. El medio enriquecido con una concentración de 10,0 μM produjo la máxima velocidad específica de crecimiento celular (0,76 día-1), mientras que las máximas productividades de biomasa y de lípidos se presentaron a la concentración 5,00 μM con valores de 112,4 mg·L-1·día-1 y 6,52 mg·L-1·día-1 respectivamente. Para las concentraciones más altas de hierro (21,5 y 50,0 μM), la microalga presentó inhibición por sustrato. Finalmente, para concentraciones menores que 10,0 μM se encontró que para una significancia del 5% la concentración del hierro no afecta significativamente la productividad de biomasa y lípidos