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Omar Torrescarvajal - One of the best experts on this subject based on the ideXlab platform.
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a systematic revision of neotropical lizards in the clade hoplocercinae squamata Iguania
Zootaxa, 2011Co-Authors: Omar Torrescarvajal, Richard Etheridge, Kevin De QueirozAbstract:The clade Hoplocercinae includes 13 species assigned to three taxa traditionally ranked as genera—Enyalioides, Hoplocercus, and Morunasaurus—, and distributed on both sides of the Andes from Panama to Brazil. We provide a revised taxonomy of Hoplocercinae including synonymies, diagnoses, standardized descriptions, distributions, notes on color and natural history, and a key for species identification. We also propose vernacular names in English and Spanish for all species.
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phylogeny of hoplocercine lizards squamata Iguania with estimates of relative divergence times
Molecular Phylogenetics and Evolution, 2009Co-Authors: Omar Torrescarvajal, Kevin De QueirozAbstract:Hoplocercine lizards form a clade of 11 currently recognized species traditionally placed in three genera (Enyalioides, Hoplocercus, and Morunasaurus) that occur in the lowlands on both sides of the Andes between Panama and the Brazilian Cerrado. We analyze 11 mitochondrial and two nuclear loci using probabilistic methods and different partitioning strategies to (1) infer the phylogenetic relationships among species of Hoplocercinae, (2) examine amounts of inter- and intraspecific sequence divergence, (3) address monophyly of four species, (4) test previous phylogenetic hypotheses, and (5) estimate divergence times. Our preferred hypothesis places H. spinosus as the sister taxon to all other species of hoplocercines, with M. annularis nested within Enyalioides. Species with multiple samples are monophyletic except for Enyalioides oshaughnessyi, which is paraphyletic relative to an undescribed species of Enyalioides. All previously published phylogenetic hypotheses for hoplocercines are rejected. Monophyly of Enyalioides cannot be rejected and, consequently, the position of Morunasaurus remains unclear. The most recent common ancestor of Hoplocercinae probably occurred east of the Andes; western taxa included in our analyses originated from at least two separate colonizations whether pre- or post-dating vicariance resulting from uplift of the Andes.
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a taxonomic revision of south american stenocercus squamata Iguania lizards
Herpetological Monographs, 2007Co-Authors: Omar TorrescarvajalAbstract:Abstract South American Stenocercus lizards occur mostly in the Andes and adjacent lowland areas from northern Colombia and Venezuela to central Argentina at elevations of 0–4000 m. In this paper, 61 species of Stenocercus are recognized, including one resurrected as S. angulifer. Morphologically, S. angulifer more closely resembles S. aculeatus. For each species, a diagnosis, description, and summary of distribution are provided based on examination of 2001 specimens and data from the literature. Notes on color in life and natural history are included for most species. Additionally, a dichotomous key to assist in the identification of specimens is provided.
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phylogeny and biogeography of a large radiation of andean lizards Iguania stenocercus
Zoologica Scripta, 2007Co-Authors: Omar TorrescarvajalAbstract:With 61 species occurring mostly in the Andes and adjacent lowland areas, Stenocercus lizards represent one of the most widespread and well-represented Andean vertebrate groups. Phylogenetic relationships among species of Stenocercus are inferred using different datasets based on mitochondrial DNA sequence data of 35 species and morphological data of 59 species. Among morphological data, polymorphic and meristic/morphometric characters are coded under the frequency parsimony and gap-weighting methods, respectively, and the accuracy of these methods is tested. When both types of characters are included, the resulting tree topology is more similar to the topologies obtained from analyses of DNA sequence data than those topologies obtained after exclusion of one or both types of characters. The phylogenetic hypotheses inferred including 59 species of Stenocercus (dataset 1) and excluding those species for which DNA data were not available (dataset 2) are generally congruent with each other, as well as with previously published hypotheses. The most parsimonious tree obtained from analysis of dataset 2 is used in a dispersal-vicariance analysis to infer ancestral areas and major biogeographical events. Species of Stenocercus are divided into two major clades. Clade A has diversified mostly in the central Andes, with a few species in the northern Andes and one species in the southern Andes. Clade B is more widespread, with species in the northern, central, and southern Andes, as well as in the Atlantic lowlands and Amazon basin. The most recent common ancestor of Stenocercus is inferred to have occurred in the eastern cordillera of the central Andes. Given morphological similarity and altitudinal distribution of some species nested in a northern-Andes clade, as well as the relatively recent uplift of this Andean region, it is possible that species in this clade have diverged as recently as the mid-Pliocene.
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phylogenetic relationships of south american lizards of the genus stenocercus squamata Iguania a new approach using a general mixture model for gene sequence data
Molecular Phylogenetics and Evolution, 2006Co-Authors: Omar Torrescarvajal, James A Schulte, John E CadleAbstract:Abstract The South American Iguanian lizard genus Stenocercus includes 54 species occurring mostly in the Andes and adjacent lowland areas from northern Venezuela and Colombia to central Argentina at elevations of 0–4000 m. Small taxon or character sampling has characterized all phylogenetic analyses of Stenocercus, which has long been recognized as sister taxon to the Tropidurus Group. In this study, we use mtDNA sequence data to perform phylogenetic analyses that include 32 species of Stenocercus and 12 outgroup taxa. Monophyly of this genus is strongly supported by maximum parsimony and Bayesian analyses. Evolutionary relationships within Stenocercus are further analyzed with a Bayesian implementation of a general mixture model, which accommodates variability in the pattern of evolution across sites. These analyses indicate a basal split of Stenocercus into two clades, one of which receives very strong statistical support. In addition, we test previous hypotheses using non-parametric and parametric statistical methods, and provide a phylogenetic classification for Stenocercus.
William E. Cooper - One of the best experts on this subject based on the ideXlab platform.
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responses to animal and plant chemicals by several Iguanian insectivores and the tuatara sphenodon punctatus
Journal of Herpetology, 2001Co-Authors: William E. Cooper, Gary W Ferguson, Jason J HabeggerAbstract:We conducted experimental tests of the responses to food chemicals presented on cotton swabs or ceramic tiles by tuataras and insectivorous species from several families of Iguanian lizards. Tu- ataras, which are primarily carnivorous, never tongue flicked but frequently bit cotton balls bearing prey surface chemicals, suggesting that they may be able to detect airborne prey chemicals via olfaction. None of the lizards tested, the agamids Chamaeleo pardalis and Acanthosaura crucigera, the polychrotids Anolis smallwoodi and Chamaeleolis chamaeleonides, the phrynosomatids Sceloporus variabilis and Uta stansburi- ana, and the crotaphytid Crotaphytus collaris, exhibited any differential responses among prey chemicals, chemicals from palatable plants, and pungency control or odorless control stimuli. The findings buttress previous work that has shown a lack of prey chemical discrimination in ambush foragers, including all sampled Iguanian insectivores. Given that all tested omnivores and herbivores respond strongly to plant chemicals, they are also consistent with the hypothesis that discriminatory lingual and biting responses to plant chemicals occur only in species having diets with a large plant component. Correlated evolution between herbivory and plant chemical discrimination remains to be established. For unknown reasons, Sceloporus variabilis tongue flicked less frequently in tile tests with romaine lettuce stimuli than with cricket and banana stimuli.
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Strike-induced chemosensory searching is absent in the cordylid lizard,Cordylus cordylus, a scleroglossan ambush forager
CHEMOECOLOGY, 1994Co-Authors: William E. Cooper, P. Le F. MoutonAbstract:Strike-induced chemosensory searching (SICS) was not detected experimentally in the cordylid lizard, Cordylus cordylus. Both components of SICS, a post-strike elevation in tongue-flick rate (PETF) and searching movements for attacked and released prey, were absent. The findings are consistent with previous data showing that PETF and/or SICS are lacking in all lizard families yet studied that forage primarily by ambush, but are present in actively foraging scleroglossan families and the herbivorous Iguanian family Iguanidae. It is suggested that foraging behavior is a primary determinant of the presence or absence of SICS in lizards. Nevertheless, in most families in the two major clades, Iguania and Scleroglossa, the plesiomorphic foraging mode is retained. The findings agree with the prediction that SICS is absent in families lacking lingually mediated prey chemical discrimination (PCD), presumably due to selection against movement by ambush foragers that avoid being detected by either prey or predators because they remain motionless. Although PETF and SICS were absent, labial-licking and lingual movements similar to those observed after swallowing increased after biting prey, suggesting that the functions of these lingual movements may have been related to grooming. Locomotory movements did not increase following biting and appeared to represent avoidance of the experimenter.
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Prey chemical discrimination and strike-induced chemosensory searching in the lizardLiolaemus zapallarensis
CHEMOECOLOGY, 1993Co-Authors: Christopher S. Deperno, William E. CooperAbstract:Experimental tests were conducted to determine whether the ambush foraging Iguanian lizard, Liolaemus zapallarensis , was capable of discriminating prey chemicals from control substances and whether this lizard exhibits strike-induced chemosensory searching (SICS) or its components after biting prey. The two components of SICS are a poststrike elevation in tongue-flicking rate (PETF) and apparent searching movements for relocation of prey that has been bitten, but released or escaped. Liolaemus zapallarensis failed to discriminate prey chemicals from control substances, but exhibited significant PETF lasting one minute. SICS was absent in L. zapallarensis because no post-strike movements were observed. The absence of both prey chemical discrimination and SICS exhibited by L. zapallarensis is common to all the insectivorous Iguanians and ambush foraging lizards studied to date. However, L. zapallarensis is the first insectivorous Iguanian species shown to exhibit PETF. The results suggest that L. zapallarensis does not use the tongue for detection, identification, or relocation of prey while foraging. The possibility does remain that L. zapallarensis may be capable of chemically identifying prey once the prey stimuli reach the oral cavity.
Guarino R Colli - One of the best experts on this subject based on the ideXlab platform.
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sperm ultrastructure of hoplocercid and oplurid lizards sauropsida squamata Iguania and the phylogeny of Iguania
Journal of Zoological Systematics and Evolutionary Research, 2007Co-Authors: Gustavo H C Vieira, Larissa D Cunha, D M Scheltinga, F Glaw, Guarino R ColliAbstract:We describe the morphology of the spermatozoa of members of the Iguanian lizard families Hoplocercidae and Opluridae for the first time. Their spermatozoa are quite similar and resemble the sperm of other Iguanian lizards. Through a re-evaluation of sperm descriptions supplied in the literature we coded continuous and discrete characters through a combination of four methods: gap-weighting, step-matrix gap-weighting, reductive coding and composite coding. Parsimony analyses revealed that different methods produced highly incongruent outcomes. In view of the pros and cons of each method, we defend that the combination between composite coding and step-matrix gap-weighting are the most appropriate for our data. The cladogram derived from this analysis is totally resolved and comparatively well supported. We conclude that although the preferred cladogram was not strongly supported in some instances, sperm characters could be a good predictor of relationships among Iguanian groups. We compare our hypothesis with preceding studies and we show that some previous groupings are in accordance with our results. Finally, we discuss the validity of those groupings in the light of methodological reasoning.
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phylogenetic relationships of corytophanid lizards Iguania squamata reptilia based on partitioned and total evidence analyses of sperm morphology gross morphology and dna data
Zoologica Scripta, 2005Co-Authors: Gustavo H C Vieira, Guarino R ColliAbstract:We conducted partitioned and combined Bayesian and parsimony phylogenetic analyses of corytophanid lizards (Iguania) using mtDNA, gross morphology, and sperm ultrastructure data sets. Bayesian and parsimony hypotheses showed little disagreement. The combined analysis, but not any of the partitioned ones, showed strong support for the monophyly of Corytophanidae and its three genera, Basiliscus, Corytophanes, and Laemanctus. Basiliscus is the sister taxon of a well-supported clade formed by Corytophanes and Laemanctus. The relationships of species within Basiliscus and Corytophanes received weak support, regardless of the method used. We defend those relationships as feasible and open to further testing. Data derived from the ultrastructure of spermatozoa are potentially a good source of characters for systematic inferences of Iguania and its major lineages. A Brooks Parsimony Analysis based on the geographic distributions of corytophanids and the phylogenetic tree obtained from the combined analysis suggested a Central American origin of the group, a recent colonization of northern South America, and the role of epeirogenic uplifts and the formation of lowlands during the late Tertiary in the differentiation of corytophanids.
Jack L. Conrad - One of the best experts on this subject based on the ideXlab platform.
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A new Late Cretaceous iguanomorph from North America and the origin of New World Pleurodonta (Squamata, Iguania)
Proceedings of The Royal Society B: Biological Sciences, 2017Co-Authors: David G. Demar, Jack L. Conrad, Jason J. Head, David J. Varricchio, Gregory P. WilsonAbstract:Iguanomorpha (stem + crown Iguania) is a diverse squamate clade with members that predominate many modern American lizard ecosystems. However, the temporal and palaeobiogeographic origins of its constituent crown clades (e.g. Pleurodonta (basilisks, iguanas, and their relatives)) are poorly constrained, mainly due to a meagre Mesozoic-age fossil record. Here, we report on two nearly complete skeletons from the Late Cretaceous (Campanian) of North America that represent a new and relatively large-bodied and possibly herbivorous iguanomorph that inhabited a semi-arid environment. The new taxon exhibits a mosaic of anatomical features traditionally used in diagnosing Iguania and non-Iguanian squamates (i.e. Scleroglossa; e.g. parietal foramen at the frontoparietal suture, astragalocalcaneal notch in the tibia, respectively). Our cladistic analysis of Squamata revealed a phylogenetic link between Campanian-age North American and East Asian stem iguanomorphs (i.e. the new taxon + Temujiniidae). These results and our evaluation of the squamate fossil record suggest that crown pleurodontans were restricted to the low-latitude Neotropics prior to their early Palaeogene first appearances in the mid-latitudes of North America.
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Phylogeny And Systematics Of Squamata (Reptilia) Based On Morphology
Bulletin of the American Museum of Natural History, 2008Co-Authors: Jack L. ConradAbstract:Squamata (amphisbaenians, ‘‘lizards’’, mosasaurs, and snakes) is an extremely diverse clade\r\nwith a rich fossil record. There is little consensus about the interrelationships of the major\r\nsquamate clades (i.e., Iguania, Gekkota, Scincomorpha, Anguimorpha, Amphisbaenia, and\r\nSerpentes), or even the membership of some of these clades. Morphology-based cladistic\r\nanalyses typically agree only that the major dichotomy in extant squamates is between Iguania\r\nand all other taxa. The phylogenetic placement of Amphisbaenia and Serpentes is particularly\r\nproblematic. Incomplete taxon sampling is likely a major contributing factor to the absence of a\r\nconsensus about squamate interrelationships. This study examines squamate relationships using\r\n222 ingroup taxa scored for 363 morphological characters. Analysis of these data recovered\r\n2,213 equally short trees with a length of 3,273 steps and a retention index of 0.7164. The results\r\nconfirm the monophyly of the clades Scleroglossa (extant squamates exclusive of Iguania),\r\nGekkota, Scincomorpha, Lacertoidea, Scincoidea, Anguimorpha, Carusioidea, Platynota, and\r\nVaranoidea. Novel results include the identification of a clade containing Scincidae sensu lato,\r\nDibamidae, Amphisbaenia, and Serpentes; identification of a Mesozoic clade containing\r\nBainguis, Eoxanta lacertifrons, Globaura venusta, and Myrmecodaptria; and identification of\r\nDalinghosaurus as a basal shinisaur. A new taxonomic scheme is outlined. The names\r\nIguanomorpha, Scincogekkonomorpha, Evansauria, and Mosasauriformes are applied to the\r\nstem-based groups including Iguania, Scleroglossa, Autarchoglossa, and Mosasauria, respectively.\r\nThe importance of strict rigidity within taxonomy is questioned; taxonomy is most useful\r\nas a tool for communication about organisms or groups of organisms
P. Le F. Mouton - One of the best experts on this subject based on the ideXlab platform.
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Strike-induced chemosensory searching is absent in the cordylid lizard,Cordylus cordylus, a scleroglossan ambush forager
CHEMOECOLOGY, 1994Co-Authors: William E. Cooper, P. Le F. MoutonAbstract:Strike-induced chemosensory searching (SICS) was not detected experimentally in the cordylid lizard, Cordylus cordylus. Both components of SICS, a post-strike elevation in tongue-flick rate (PETF) and searching movements for attacked and released prey, were absent. The findings are consistent with previous data showing that PETF and/or SICS are lacking in all lizard families yet studied that forage primarily by ambush, but are present in actively foraging scleroglossan families and the herbivorous Iguanian family Iguanidae. It is suggested that foraging behavior is a primary determinant of the presence or absence of SICS in lizards. Nevertheless, in most families in the two major clades, Iguania and Scleroglossa, the plesiomorphic foraging mode is retained. The findings agree with the prediction that SICS is absent in families lacking lingually mediated prey chemical discrimination (PCD), presumably due to selection against movement by ambush foragers that avoid being detected by either prey or predators because they remain motionless. Although PETF and SICS were absent, labial-licking and lingual movements similar to those observed after swallowing increased after biting prey, suggesting that the functions of these lingual movements may have been related to grooming. Locomotory movements did not increase following biting and appeared to represent avoidance of the experimenter.
