Results 131 to 140 of about 1,230 (177)
Some of the next articles are maybe not open access.
Diverse Activity Rhythms in Sharks (Elasmobranchii)
Journal of Biological Rhythms, 2020Sharks are an interesting group of vertebrates, as many species swim continuously to “ram” oxygen-rich seawater over their gills (ram ventilators), whereas other species “pump” seawater over their gills by manipulating buccal cavity volume while remaining motionless (buccal pumpers).
Michael L. Kelly +6 more
openaire +2 more sources
THE RETENTION AND PHYSIOLOGICAL ROLE OF UREA IN THE ELASMOBRANCHII
Biological Reviews, 1936Summary.The high urea content (2·0 and 2·5 per cent.) that characterises the blood, body fluids and tissues of the Elasmobranchii owes its origin to the relative impermeability of the gills and integument to this substance, and to the circumstance that the urea is actively conserved by the elasmobranch kidney.In consequence of this physiological ...
Homer W Smith
exaly +2 more sources
The selective drivers of allometry in sharks (Chondrichthyes: Elasmobranchii)
Zoological Journal of the Linnean Society, 2023AbstractIn addition to the selective importance of interspecific morphological variation, ontogenetic morphological variation may reflect different selective regimes to which successive developmental stages are subjected. The typical body form of carcharhiniform sharks is considered relatively conserved, yet sharks exhibit a wide range of body sizes ...
Joel H Gayford +3 more
openaire +2 more sources
Occipital spine ofOrthacanthus (Xenacanthidae, Elasmobranchii): Structure and growth
Journal of Morphology, 1999The morphology of 16 occipital spines of the xenacanthid Orthacanthus from Upper Carboniferous deposits of Robinson (Kansas, USA), Nýran (Czech Republic) and Puertollano (Spain) is described. The nonreplaced spines reveal the growth pattern of the shark.
Rodrigo Soler-Gijón
exaly +3 more sources
Ventricular fluid production rates and turnover in elasmobranchii
Comparative Biochemistry and Physiology, 1964Abstract 1. 1. Ventricular fluid (VF) production rates were measured by frontocerebellar perfusion with buffered inulin solution in three species of sharks; the spiny dogfish ( Squalus acanthia ). the nurse shark ( Ginglymostoma cirratum ) and the lemon shark ( Negaprion brevirostris ). 2. 2.
W W, OPPELT +3 more
openaire +2 more sources
Management of Sharks and Their Relatives (Elasmobranchii)
Fisheries, 2000(2000). Management of Sharks and Their Relatives (Elasmobranchii) Fisheries: Vol. 25, No. 3, pp. 9-13.
J. A. Musick +4 more
openaire +1 more source
Journal of Morphology, 2021
Abstract The morphology of the articular region of the pectoral girdle and associated basals in Etmopteridae is revised in light of new evidence provided by taxa unavailable for previous studies. Such studies considered that etmopterids plesiomorphically had a single pectoral articular condyle, and only
João Paulo Capretz Batista Da Silva +1 more
openaire +2 more sources
Abstract The morphology of the articular region of the pectoral girdle and associated basals in Etmopteridae is revised in light of new evidence provided by taxa unavailable for previous studies. Such studies considered that etmopterids plesiomorphically had a single pectoral articular condyle, and only
João Paulo Capretz Batista Da Silva +1 more
openaire +2 more sources
Smooth muscle “microsphincters” in the gastric mucosa of stingrays (Elasmobranchii, Dasyatidae)
Journal of Fish Biology, 2023AbstractThe occurrence of smooth muscle sphincters around gastric gland tubules in the cardiac stomach of some elasmobranch species is reported for the first time. These “microsphincters” took the form of a twisted torus, approximately 12–16 muscle fibres thick, that could fully constrict the gland tubules.
Aaron C. Henderson +2 more
openaire +2 more sources
Dentine structure in the rostral teeth of the sawfish Pristis (Elasmobranchii)
Archives of Oral Biology, 1980Abstract Scanning and transmission electron microscopy showed that the osteodentine has a unique arrangement of matrix collagen fibres. Except in the regions immediately surrounding the pulp canals, where the fibres form a feltwork, the dentine is composed of thick bundles of closely packed, mineralized collagen fibres orientated parallel with the ...
R P, Shellis, B K, Berkovitz
openaire +2 more sources
THE WIDESPREAD OCCURRENCE OF A CORTICOSTEROID 1α-HYDROXYLASE IN THE INTERRENALS OF ELASMOBRANCHII
Journal of Endocrinology, 1968SUMMARY A corticosteroid 1α-hydroxylase was demonstrated in interrenal tissue of eleven species of elasmobranchs by the production in vitro of 1α-hydroxycorticosterone from corticosterone, and in seven of nine species examined from endogenous precursors.
B, Truscott, D R, Idler
openaire +2 more sources