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Showing 1 to 20 of 23 for “"elasmobranchs"”.
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Inner ear morphology in elasmobranchs: implications for auditory capacity and ecology
Elasmobranchs (sharks, rays, and skates) represent the majority of Chondrichthyan species, a clade of cartilaginous fishes that first appeared over 400 million years ago. Given their basal position in the evolutionary tree of gnathostomes, elasmobranchs can provide key insights into the early …
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Diencephalic asymmetries: morphological, immunohistochemical and ultrastructural analysis of habenular nuclei in elasmobranchs and teleosts
… al., 1983). For the present study 14 species of Elasmobranchs and 15 species of Teleostean have been used. Brains removed from the animals have been fixed using 4% paraformaldehyde in phosphate buffer; brains have been analyzed with different tecniques, and I used histological, …
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e(lasmo)DNA : the role of environmental DNA (eDNA) analysis in marine fish biodiversity assessment, with special focus on elasmobranchs
… strategies for taxa like teleosts and elasmobranchs, depends on the accurate assessment and monitoring of the distribution and abundance of target species. However, detecting species occurrences is often even more challenging in the aquatic environment than on land. Consequently, as is …
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The Elasmobranch-Microbe Relationship: Trimethylamine n-oxide Synthesis, Urea Hydrolysis, and Microbe-Osmolyte Interactions in the Atlantic Stingray, <i>Dasyatis sabina</i>
… of these plasma osmolytes, it is notable that elasmobranchs appear to lack urease and TMA oxidase (Tmase), enzymes that scavenge urea-nitrogen and synthesize TMAO, respectively. However, urease and Tmase are found in many species of bacteria. Therefore, I hypothesized that intestinal bacteria …
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Regulation of Glucose Uptake and Transporter Expression in the North Pacific Spiny Dogfish (Squalus suckleyi)
Elasmobranchs (sharks, skates, and rays) are a primarily carnivorous group of vertebrates that consume very few carbohydrates and have little reliance on glucose as an oxidative fuel, the one exception being the rectal gland. This has led to a dearth of information on glucose transport and …
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Aquaporin 3 Water Channel Protein Gene Expression in Squalis Acanthias Dogfish Shark
… the role of AQP3 in water homeostasis of marine elasmobranchs such as Squalus acanthias is yet to be described.
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Studies on the osmotic and ionic regulation of the striped dogfish Poroderma africanum (Gmelin)
… work on the osmoregulation of marine elasmobranchs has been carried out in the South African region. The species chosen was also considered interesting in view of its common occurrence around the Cape (at the time of commencement of the work) and the fact that it seemed to be …
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Decoding the Little Skate Retina: Structural Variants and Developmental Dynamics
<p>The retinal development of Elasmobranchs (the superclass comprising sharks, skates and rays) is a poorly understood phenomenon, but it represents a critical component of the broader picture of vertebrate visual development. Evolutionary divergence between these organisms and the mammals is vast, …
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Decoding the Little Skate Retina: Structural Variants and Developmental Dynamics
<p>The retinal development of Elasmobranchs (the superclass comprising sharks, skates and rays) is a poorly understood phenomenon, but it represents a critical component of the broader picture of vertebrate visual development. Evolutionary divergence between these organisms and the mammals is vast, …
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Age, growth, and reproductive biology, of the winter skate, Leucoraja ocellata, in the western Gulf of Maine
… succinct reproductive cycle. Like many other elasmobranchs, these characteristics make L. ocellata 's populations highly susceptible to exploitation by commercial fisheries.</p>
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Development and Employment of Environmental DNA Methods for the Detection of Bull Sharks (<i>Carcharhinus leucas</i>) in a Freshwater and Estuarine Interface in the Mobile-Tensaw Delta and Mobile Bay, Alabama
… but ecologically significant species, like elasmobranchs. Bull Sharks (<em>Carcharhinus leucas</em>) are highly mobile predators that rely on estuaries and freshwater rivers for maturation, resources, and refuge; their ability to withstand changing environmental conditions may mean they are …
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Detection, Activity Measurement and Phylogeny of Ureolytic Bacteria Isolated from Elasmobranch Tissue
… indicated bacteria community structure in both elasmobranchs were under phylum Proteobacteria, Firmicutes and Actinobacteria. By conducting split-plot ANOVA, we found the microbial richness is significantly different (P=0.0814) between two superorders of elasmobranch, which may largely due to …
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Aerobic and anaerobic activity metabolism of an elasmobranch
… to anthropogenic or environmental stressors. Elasmobranchs, in particular, represent some of the most exploited vertebrate taxa on the planet, and many species are data deficient with regard to a basic understanding of energetics or how stressors alter patterns of energy use and allocation. …
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Instrumental conditioning and learning in Poroderma Pantherinum
… functions and learning occur in teleosts and elasmobranchs. Very little is known about the cognitive abilities of benthic sharks and no research has been published on the learning ability of the endemic Leopard catshark (Poroderma pantherinum) species of South Africa. This species is listed as …
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Analisi della variabilità genetica e della connettività tra popolazioni di due specie di Elasmobranchi: Raja clavata L.,1758 e Scyliorhinus canicula (L., 1758)
… Taking into account the vulnerability of elasmobranchs, due to of their biological characteristics (low fecundity, late maturity and slow growth rates), they are mainly affected by anthropic influence, as fishing pressure. In fact, there is evidence that the elasmobranchs of the …
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The biology and macroparasites of the sixgill sawshark Pliotrema warreni
… to the guidelines for age determination for elasmobranchs provided in the literature, the conventional method used which involved extensive cleaning of the vertebral centra with an array of chemicals, setting and cutting in an epoxy resin, and staining for microscopy, did not yield readable …
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Evaluating the Conservation and Ecological Roles of Large Marine Protected Areas for Threatened Sharks
Sharks are among the most threatened groups of vertebrates on the planet, in large part due to historical and ongoing overfishing, both via targeted exploitation as well as bycatch. In recent years, shark conservation has gained increased international attention, particularly with respect to …
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Investigating the movement and foraging ecology of reef manta rays (Mobula alfredi) in the Chagos Archipelago
… rays (Mobula alfredi) are large zooplanktivorous elasmobranchs of the family Mobulidae. The species is dispersed throughout the Indian and West Pacific Oceans in small, isolated populations that tend to have a limited home range. Individuals within a population regularly visit specific locations …
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Protozoi ed Elminti parassiti dei molluschi cefalopodi delle acque circostanti la Sardegna. Morfologia, sistematica, epidemiologia, possibile utilizzo dei parassiti come indicatori bioecologici
… top predators as cetaceans, scombrids, and elasmobranchs rispectively. A decrease in the abundance of parasites relatively to depth of trawl samplings was observed, excepted for that of Lappetascaris sp. Type A whose this infection index was very higher in lower bottoms. Given also the fact …
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Factors influencing the nursery dynamics of juvenile bull sharks in two estuaries along the Texas coast
Nursery habitats provide refuge for juvenile organisms to grow and develop, and are utilized by several shark species, including bull sharks (Carcharhinus leucas). Bull sharks utilize estuaries adjoining the Gulf of Mexico as nursery habitat, and are the most abundant shark species found along the …
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