The mating season of the Atlantic stingray (Dasyatis sabina), which begins in August and continues through April, is the longest documented for any elasmobranch fish. Despite this protracted mating period, female stingrays ovulate synchronously at the end of the mating season and there is no evidence for sperm storage by females. Thus, the proximate causal factors and ultimate function of this ...

The horn sharks (Heterodontidae: Chondrichthyes) represent one of four independent evolutions of durophagy in the cartilaginous fishes. We used high-resolution computed tomography (CT scanning) to visualize and quantify the mineralized tissue of an ontogenetic series of horn sharks. CT scanning of neonatal through adult California horn sharks (Heterodontus francisci) confirmed that this techniq...

Glutamine synthetase is present as isozymic forms in the elasmobranchs Squalus acanthias (dogfish shark) and Dasyatis sabina (stingray). Subcellular fractionation of elasmobranch brain and liver tissue shows the enzyme to be predominantly cytosolic in the former tissue and mitochondrial in the latter. For the cytosolic brain enzyme, the subunit Mr equals 42,000 in the stingray and 45,000 in the...

Visualization of Calcified Shark Cartilage (And Other Stubborn Heterogeneous Skeletal Tissues) Mason N. Dean, Stanislav N. Gorb & Adam P. Summers Ecology & Evolutionary Biology, University of California Irvine, Irvine, CA USA Evolutionary Biomaterials Group, Max Planck Institute for Metals Research, Stuttgart, Germany [email protected] Biological materials interest biologists and engineers for thei...

The yellow stingray, Urobatis jamaicensis (family Urolophidae), a short-lived, relatively small elasmobranch species (35--40 cm total length), is a common inhabitant of hard bottom and coral reef communities in southeastern Florida and many parts of the Caribbean. A paucity of published studies deal with the yellow stingray, none however on the gross morphology of its nervous system. The gross ...

The yellow stingray, Urobatis jamaicensis (family Urolophidae), a short-lived, relatively small elasmobranch species (35--40 cm total length), is a common inhabitant of hard bottom and coral reef communities in southeastern Florida and many parts of the Caribbean. A paucity of published studies deal with the yellow stingray, none however on the gross morphology of its nervous system. The gross ...