| complete mitochondrial dna sequences of six snakes: phylogenetic relationships and molecular evolution of genomic features. | complete mitochondrial dna (mtdna) sequences were determined for representative species from six snake families: the acrochordid little file snake, the bold boa constrictor, the cylindrophiid red pipe snake, the viperid himehabu, the pythonid ball python, and the xenopeltid sunbeam snake. thirteen protein-coding genes, 22 trna genes, 2 rrna genes, and 2 control regions were identified in these mtdnas. duplication of the control region and translocation of the trnaleu gene were two notable featur ... | 2005 | 16007493 |
| the development of the skull in acrochordus granulatus (schneider) (reptilia: serpentes), with special consideration of the otico-occipital complex. | the skull of acrochordus has been characterized by the absence of a crista circumfenestralis (a synapomorphy shared by all snakes), and by the absence of a recessus scalae tympani that in other squamates forms by subdivision of the embryonic metotic fissure. these traits have variably been identified as either plesiomorphic or paedomorphic. the study of the development of the osteocranium in a series of cleared and stained embryos of acrochordus shows a close correspondence to the development of ... | 2001 | 11517468 |
| pulmonary blood flow regulation in an aquatic snake. | regulation of pulmonary blood flow was studied during voluntary diving in the aquatic file snake, acrochordus granulatus. measurements of pressure and blood flow in pulmonary and systemic vessels indicate that blood flow completely bypasses the lung for significant periods during prolonged and quiescent submergence (greater than 30 minutes). when the lung is ventilated, pulmonary blood flow increases to 36 milliliters per minute per kilogram of body mass (measured in the anterior pulmonary arter ... | 1989 | 2749262 |
| adrenergic nerves and 5-hydroxytryptamine-containing cells in the pulmonary vasculature of the aquatic file snake acrochordus granulatus. | the adrenergic innervation of the pulmonary vasculature of the file snake acrochordus granulatus was examined by use of glyoxylic acid-induced fluorescence. perivascular plexuses of blue-green fluorescent nerves are observed around the common pulmonary artery, the anterior and posterior pulmonary arteries, the arterioles leading to the gas exchange capillaries of the lung, the venules draining the lung, and the anterior and posterior pulmonary veins. adrenergic nerves are also associated with th ... | 1989 | 2713887 |
| vasoactive intestinal polypeptide-immunoreactive nerves in the pulmonary vasculature of the aquatic file snake acrochordus granulatus. | the indirect immunofluorescence technique was used to determine the distribution of vasoactive intestinal polypeptide-immunoreactive and somatostatin-immunoreactive axons in the pulmonary vasculature of the aquatic file snake acrochordus granulatus. a dense distribution of vasoactive intestinal polypeptide-immunoreactive axons was found on the common pulmonary artery, the anterior and posterior pulmonary arteries, and the smaller arteries branching to the lung. the density of these axons appeare ... | 1989 | 2565165 |
| karyological studies on six species of indian snakes (colubridae: reptilia). | detailed chromosomal analyses have been carried on six species of snakes, viz. ahaetulla nasutus, chrysopelea ornata, dendrelaphis ahaetulla, xenochrophis piscator, enhydris enhydris and acrochordus granulatus. on the basis of these studies, evidence is presented to show that inversions, and in some instances centric fissions and translocations, have played an important role in bringing about structural repatterning in this group, and that the subfamily acrochordinae is the most primitive, so fa ... | 1980 | 7428439 |
| chromosomal polymorphism in three species of indian snakes. | interesting results regarding the polymorphic state of one or more pairs of macro-chromosomes in three species of colubrid snakes viz., ahaetulla nasutus, chrysopelea ornate and acrochordus granulatus were obtained. morphological variations were statistically estimated and idiograms prepared. these observations, when compared with those of the normal karyotypes, confirmed that the centric shifts were real and in all probability due to pericentric inversions. such observations yield significant i ... | 1979 | 527373 |
| ontogenetic shifts of heart position in snakes. | heart position relative to total body length (tl) varies among snakes, with anterior hearts in arboreal species and more centrally located hearts in aquatic or ground-dwelling species. anterior hearts decrease the cardiac work associated with cranial blood flow and minimize drops in cranial pressure and flow during head-up climbing. here, we investigate whether heart position shifts intraspecifically during ontogenetic increases in tl. insular florida cottonmouth snakes, agkistrodon conanti, are ... | 2017 | 28470824 |
| observations on the sexual segment of the kidney of snakes with emphasis on ultrastructure in the yellow-bellied sea snake, pelamis platurus. | the sexual segment of the kidney (ssk) is an accessory sex structure in male lizards and snakes (squamata). we describe histology of the ssk in 12 species of snakes, including one from the basal scolecophidia, leptotyphlops dulcis, and from the more advanced alethinophidia, species from the acrochordidae (acrochordus granulatus), homalopsidae (cerberus rynchops), uropeltidae (teretrurus sanguineus), and eight species from the elapidae, including six species of sea snakes. we also describe the ul ... | 2012 | 22396145 |
| structure and function of skin in the pelagic sea snake, hydrophis platurus. | we describe and interpret the functional morphology of skin of the yellow-bellied sea snake, hydrophis platurus. this is the only pelagic sea snake, and its integument differs from what is known for other species of snakes. in gross appearance, the scales of h. platurus consist of non-overlapping, polygonal knobs with flattened outer surfaces bearing presumptive filamentous sensillae. the deep recesses between scales ('hinge') entrap and wick water over the body surface, with mean retention of 5 ... | 2019 | 30779371 |
| dehydration and drinking behavior of the marine file snake acrochordus granulatus. | dehydration and drinking behaviors were investigated in the little file snake (acrochordus granulatus) collected from marine populations in the philippines and in australia. file snakes dehydrate in seawater and do not drink seawater when dehydrated in air and offered seawater to drink. dehydrated file snakes drink freshwater, and the threshold of dehydration for first drinking response is a deficit of -7.4% ± 2.73% (mean ± sd) of original body mass. the thirst mechanism in this species is more ... | 2014 | 24457920 |
| is aquatic life correlated with an increased hematocrit in snakes? | physiological adaptations that allow air-breathing vertebrates to remain underwater for long periods mainly involve modifications of the respiratory system, essentially through increased oxygen reserves. physiological constraints on dive duration tend to be less critical for ectotherms than for endotherms because the former have lower mass-specific metabolic rates. moreover, comparative studies between marine and terrestrial ectotherms have yet to show overall distinct physiological differences ... | 2011 | 21359216 |