The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Robert W Henderson - One of the best experts on this subject based on the ideXlab platform.
-
ecological notes on the annulated treeboa Corallus annulatus from a costa rican lowland tropical wet forest
arXiv: Quantitative Methods, 2020Co-Authors: Todd R Lewis, Robert W Henderson, Paul B C Grant, Alex Figueroa, Mike D DunnAbstract:The Annulated Treeboa (Corallus annulatus) is one of nine currently recognized species in the boid genus Corallus. Its disjunct range extends from eastern Guatemala into northern Honduras, southeastern Nicaragua, northeastern Costa Rica, and southwestern Panama to northern Colombia west of the Andes. It is the only species of Corallus found on the Caribbean versant of Costa Rica, where it occurs at elevations to at least 650m and perhaps as high as 1,000m. Corallus annulatus occurs mostly in primary and secondary lowland tropical wet and moist rainforest and it appears to be genuinely rare. Besides C. cropanii and C. blombergi (the latter closely related to C. annulatus), it is the rarest member of the genus. Aside from information on habitat and activity, little is known regarding its natural history.
-
canopy foraging by Corallus caninus squamata boidae in french guiana
Herpetology Notes, 2015Co-Authors: Mael Dewynter, Vincent Premel, Robert W HendersonAbstract:Corallus exhibit both active and sit-and-wait (ambush) foraging strategies (e.g., C. cookii, C. grenadensis, C. hortulanus, C. ruschenbergerii), it has been suggested that at least two species (C. batesii, C. caninus) likely employ ambush foraging throughout their lives (Henderson, 2015). The species that exhibit both foraging modes are relatively slender compared to those species that might employ only the ambush mode, and they display an ontogenetic shift in diet from either diurnally quiescent lizards (for C. cookii and C. grenadensis) or birds (C. hortulanus) to one comprised mainly of nocturnally active rodents and/or marsupials. The large-headed, heavy-bodied C. batesii and C. caninus, on the other hand, prey predominantly on rodents and marsupials throughout their lives (although small, nocturnally active reptiles have been documented in their diets) (Henderson and Pauers, 2009; Henderson et al., 2013; Henderson, 2015). Previous observations in the field have documented adult C. batesii (Henderson, 2015: Fig. 210), C. grenadensis (Henderson, 2015: Fig. 221), and C. hortulanus (Henderson, 2015: Fig. 242) in what we consider to be typical sit-and-wait ambush postures. In all cases, the tail and posterior body were anchored to a slender tree trunk or branch and the head was angled downward and usually within 1.0 m of the ground (and sometimes much closer). We have assumed that, like other species of Corallus, not all foraging in C. batesii and C. caninus occurs near ground level. On 31 January 2015 at 2055 h, one of us (VP) encountered an adult C. caninus near a creek in secondary forest at a site near Kourou, French Guiana. Herpetology Notes, volume 8: 561-562 (2015) (published online on 06 December 2015)
-
mating behavior of amazon treeboas Corallus hortulanus squamata boidae on batatas island piaui brazil
2014Co-Authors: Pedro Da Costa Silva, Robert W HendersonAbstract:directions. At 2031 h the male oriented its head toward that of the female and rubbed its chin on the female’s neck several times before turning to again face in the opposite direction. At 2032 h the male again oriented its head toward that of the female, again rubbing his chin on the female’s neck and head; they remained in that position for eight minutes. At 2045 h, both boas had their heads oriented toward the end of the branch
-
on the congruence of morphology trophic ecology and phylogeny in neotropical treeboas squamata boidae Corallus
Biological Journal of The Linnean Society, 2013Co-Authors: Robert W Henderson, Michael J Pauers, Timothy J ColstonAbstract:Nine members of the Neotropical treeboa genus Corallus occur from Guatemala to south-eastern Brazil and recent studies have provided an inconclusive picture about the relationship between morphology and trophic ecology in these snakes. To construct a more complete picture, we conducted the first study of morphology and diet to consider all nine species. Using adult specimens from museum collections, we examined several morphometric and meristic variables and their possible relationship to Corallus diets. Broadly, we found three basic morphologies within the genus: a short, narrow head and a slender body (C. cookii, C. grenadensis, C. hortulanus, and C. ruschenbergerii), useful for exploiting a wide variety of prey; a relatively stout body with a long, wide head (C. batesii, C. caninus, and C. cropanii) associated with feeding on larger mammalian prey; and an intermediate morphology, found in C. annulatus and C. blombergii, which may be indicative of endotherm generalists. These morphological and dietary patterns exhibit a strong degree of congruence with a recent molecular phylogeny of Corallus and highlight a heretofore unexamined ecological diversification within Corallus. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 466–475.
-
molecular systematics and historical biogeography of tree boas Corallus spp
Molecular Phylogenetics and Evolution, 2013Co-Authors: Timothy J Colston, Robert W Henderson, Felipe G Grazziotin, Donald B Shepard, Laurie J Vitt, Guarino R Colli, Blair S Hedges, Sandro L Bonatto, Hussam ZaherAbstract:Inferring the evolutionary and biogeographic history of taxa occurring in a particular region is one way to determine the processes by which the biodiversity of that region originated. Tree boas of the genus Corallus are an ancient clade and occur throughout Central and South America and the Lesser Antilles, making it an excellent group for investigating Neotropical biogeography. Using sequenced portions of two mitochondrial and three nuclear loci for individuals of all recognized species of Corallus, we infer phylogenetic relationships, present the first molecular analysis of the phylogenetic placement of the enigmatic C. cropanii, develop a time-calibrated phylogeny, and explore the biogeographic history of the genus. We found that Corallus diversified within mainland South America, via over-water dispersals to the Lesser Antilles and Central America, and via the traditionally recognized Panamanian land bridge. Divergence time estimates reject the South American Caribbean-Track as a general biogeographic model for Corallus and implicate a role for events during the Oligocene and Miocene in diversification such as marine incursions and the uplift of the Andes. Our findings also suggest that recognition of the island endemic species, C. grenadensis and C. cookii, is questionable as they are nested within the widely distributed species, C. hortulanus. Our results highlight the importance of using widespread taxa when forming and testing biogeographic hypotheses in complex regions and further illustrate the difficulty of forming broadly applicable hypotheses regarding patterns of diversification in the Neotropical region.
Blair S Hedges - One of the best experts on this subject based on the ideXlab platform.
-
molecular systematics and historical biogeography of tree boas Corallus spp
Molecular Phylogenetics and Evolution, 2013Co-Authors: Timothy J Colston, Robert W Henderson, Felipe G Grazziotin, Donald B Shepard, Laurie J Vitt, Guarino R Colli, Blair S Hedges, Sandro L Bonatto, Hussam ZaherAbstract:Inferring the evolutionary and biogeographic history of taxa occurring in a particular region is one way to determine the processes by which the biodiversity of that region originated. Tree boas of the genus Corallus are an ancient clade and occur throughout Central and South America and the Lesser Antilles, making it an excellent group for investigating Neotropical biogeography. Using sequenced portions of two mitochondrial and three nuclear loci for individuals of all recognized species of Corallus, we infer phylogenetic relationships, present the first molecular analysis of the phylogenetic placement of the enigmatic C. cropanii, develop a time-calibrated phylogeny, and explore the biogeographic history of the genus. We found that Corallus diversified within mainland South America, via over-water dispersals to the Lesser Antilles and Central America, and via the traditionally recognized Panamanian land bridge. Divergence time estimates reject the South American Caribbean-Track as a general biogeographic model for Corallus and implicate a role for events during the Oligocene and Miocene in diversification such as marine incursions and the uplift of the Andes. Our findings also suggest that recognition of the island endemic species, C. grenadensis and C. cookii, is questionable as they are nested within the widely distributed species, C. hortulanus. Our results highlight the importance of using widespread taxa when forming and testing biogeographic hypotheses in complex regions and further illustrate the difficulty of forming broadly applicable hypotheses regarding patterns of diversification in the Neotropical region.
-
a phylogenetic study of the emerald treeboa Corallus caninus
Journal of Herpetology, 2005Co-Authors: Nicolas Vidal, Robert W Henderson, Annesophie Delmas, Blair S HedgesAbstract:Phylogenetic relationships of Corallus caninus phylogeny were examined with DNA samples from five geographically disparate localities from across the range of the species (Guyana, Venezuela, Brazilian states of Paraand Rondonia, and Peru). The Peruvian sequence was the most divergent (16.2%) and the closest relative of a clade including Brazilian, Guyanan, and Venezuelan populations. Within the latter clade, the most basal lineage was from the state of Para ´, followed by the state of Rondonia, which was the closest relative of populations from the Guiana Shield. Preliminary morphological data paralleled molecular results, and it is likely that a separate species of Corallus currently included in C. caninus occurs in the upper Amazon.
-
origin of west indian populations of the geographically widespread boa Corallus enydris inferred from mitochondrial dna sequences
Molecular Phylogenetics and Evolution, 1995Co-Authors: Robert W Henderson, Blair S HedgesAbstract:Abstract Corallus enydris (Serpentes: Boidae: Boinae) is an arboreal snake with an extremely wide mainland distribution from southern Costa Rica to southeastern Brazil and is one of two home species that has invaded the Lesser Antilles (Grenada Bank and St. Vincent). Mitochondrial DNA sequences of samples from seven geographically disparate localities provided evidence of phylogenetic relationships. The monophyly of C. enydris is corroborated and a major dichotomy between northern samples (Panama and Trinidad) and southern samples (Guyana, Peru, southeastern Brazil) was found and corresponds to the two currently recognized subspecies. Unexpectedly, the two samples from the West Indies (southern Lesser Antilles) cluster with the southern rather than the geographically closer northern samples (e.g., Trinidad). The results imply a fairly recent Guianan–Amazonian origin of West Indian populations.
Timothy J Colston - One of the best experts on this subject based on the ideXlab platform.
-
on the congruence of morphology trophic ecology and phylogeny in neotropical treeboas squamata boidae Corallus
Biological Journal of The Linnean Society, 2013Co-Authors: Robert W Henderson, Michael J Pauers, Timothy J ColstonAbstract:Nine members of the Neotropical treeboa genus Corallus occur from Guatemala to south-eastern Brazil and recent studies have provided an inconclusive picture about the relationship between morphology and trophic ecology in these snakes. To construct a more complete picture, we conducted the first study of morphology and diet to consider all nine species. Using adult specimens from museum collections, we examined several morphometric and meristic variables and their possible relationship to Corallus diets. Broadly, we found three basic morphologies within the genus: a short, narrow head and a slender body (C. cookii, C. grenadensis, C. hortulanus, and C. ruschenbergerii), useful for exploiting a wide variety of prey; a relatively stout body with a long, wide head (C. batesii, C. caninus, and C. cropanii) associated with feeding on larger mammalian prey; and an intermediate morphology, found in C. annulatus and C. blombergii, which may be indicative of endotherm generalists. These morphological and dietary patterns exhibit a strong degree of congruence with a recent molecular phylogeny of Corallus and highlight a heretofore unexamined ecological diversification within Corallus. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 466–475.
-
molecular systematics and historical biogeography of tree boas Corallus spp
Molecular Phylogenetics and Evolution, 2013Co-Authors: Timothy J Colston, Robert W Henderson, Felipe G Grazziotin, Donald B Shepard, Laurie J Vitt, Guarino R Colli, Blair S Hedges, Sandro L Bonatto, Hussam ZaherAbstract:Inferring the evolutionary and biogeographic history of taxa occurring in a particular region is one way to determine the processes by which the biodiversity of that region originated. Tree boas of the genus Corallus are an ancient clade and occur throughout Central and South America and the Lesser Antilles, making it an excellent group for investigating Neotropical biogeography. Using sequenced portions of two mitochondrial and three nuclear loci for individuals of all recognized species of Corallus, we infer phylogenetic relationships, present the first molecular analysis of the phylogenetic placement of the enigmatic C. cropanii, develop a time-calibrated phylogeny, and explore the biogeographic history of the genus. We found that Corallus diversified within mainland South America, via over-water dispersals to the Lesser Antilles and Central America, and via the traditionally recognized Panamanian land bridge. Divergence time estimates reject the South American Caribbean-Track as a general biogeographic model for Corallus and implicate a role for events during the Oligocene and Miocene in diversification such as marine incursions and the uplift of the Andes. Our findings also suggest that recognition of the island endemic species, C. grenadensis and C. cookii, is questionable as they are nested within the widely distributed species, C. hortulanus. Our results highlight the importance of using widespread taxa when forming and testing biogeographic hypotheses in complex regions and further illustrate the difficulty of forming broadly applicable hypotheses regarding patterns of diversification in the Neotropical region.
Michael J Pauers - One of the best experts on this subject based on the ideXlab platform.
-
on the congruence of morphology trophic ecology and phylogeny in neotropical treeboas squamata boidae Corallus
Biological Journal of The Linnean Society, 2013Co-Authors: Robert W Henderson, Michael J Pauers, Timothy J ColstonAbstract:Nine members of the Neotropical treeboa genus Corallus occur from Guatemala to south-eastern Brazil and recent studies have provided an inconclusive picture about the relationship between morphology and trophic ecology in these snakes. To construct a more complete picture, we conducted the first study of morphology and diet to consider all nine species. Using adult specimens from museum collections, we examined several morphometric and meristic variables and their possible relationship to Corallus diets. Broadly, we found three basic morphologies within the genus: a short, narrow head and a slender body (C. cookii, C. grenadensis, C. hortulanus, and C. ruschenbergerii), useful for exploiting a wide variety of prey; a relatively stout body with a long, wide head (C. batesii, C. caninus, and C. cropanii) associated with feeding on larger mammalian prey; and an intermediate morphology, found in C. annulatus and C. blombergii, which may be indicative of endotherm generalists. These morphological and dietary patterns exhibit a strong degree of congruence with a recent molecular phylogeny of Corallus and highlight a heretofore unexamined ecological diversification within Corallus. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 466–475.
-
on the diets of neotropical treeboas squamata boidae Corallus 1
South American Journal of Herpetology, 2012Co-Authors: Robert W Henderson, Michael J PauersAbstract:ABSTRACT. Nine species of the Neotropical boid genus Corallus are distributed from southeastern Guatemala to southeastern Brazil. Based largely on previously published papers, we accumulated 271 prey records for all species combined, and they comprised 2 frogs, 69 lizards (mostly Anolis), 1 snake, 65 birds, and 134 mammals (marsupials, rodents, bats). There is a conspicuous difference in diet between the two West Indian species (C. cookii and C. grenadensis) and species occurring on the mainland: juvenile and subadult boas from the West Indies prey almost entirely on anoles, whereas on the mainland (with the notable exceptions of C. batesii and C. caninus), those age classes prey largely on birds and bats. Four species (C. cookii, C. grenadensis, C. hortulanus, and C. ruschenbergerii) are vertebrate generalists and exhibit both active and ambush foraging modes. Adult C. batesii and C. caninus (and, perhaps, C. cropanii) are specialists on mammalian prey, may only utilize an ambush foraging mode, and were ...
Stanislav N. Gorb - One of the best experts on this subject based on the ideXlab platform.
-
surface structure and frictional properties of the skin of the amazon tree boa Corallus hortulanus squamata boidae
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2009Co-Authors: R A Berthe, Guido Westhoff, Horst Bleckmann, Stanislav N. GorbAbstract:The legless locomotion of snakes requires specific adaptations of their ventral scales to maintain friction force in different directions. The skin microornamentation of the snake Corallus hortulanus was studied by means of scanning electron microscopy and the friction properties of the skin were tested on substrates of different roughness. Skin samples from various parts of the body (dorsal, lateral, ventral) were compared. Dorsal and lateral scales showed similar, net-like microornamentation and similar friction coefficients. Average friction coefficients for dorsal and lateral scales on the epoxy resin surfaces were 0.331 and 0.323, respectively. In contrast, ventral scales possess ridges running parallel to the longitudinal body axis. They demonstrated a significantly lower friction coefficient compared to both dorsal and lateral scales (0.191 on average). In addition, ventral scales showed frictional anisotropy comparing longitudinal and perpendicular direction of the ridges. This study clearly demonstrates that different skin microstructure is responsible for different frictional properties in different body regions.