Search results for "Myliobatiformes"
showing 2 items of 2 documents
Os carcharhiniformes (cCondrichthyes, Neoselachii) da Bacia de Alvalade (Portugal)
2021
The uppermost Miocene, Esbarrondadoiro Formation (Alvalade basin, Portugal) yielded more than 10 thousandSelachian teeth at Santa Margarida, Esbarrondadoiro and Vale de Zebro outcrops. Forty-five taxa were identifiedbelonging to the orders Hexanchiformes, Squaliformes, Lamniformes, Carcharhiniformes, Torpediniformes and Myliobatiformes. The Carcharhiniformes make up about 40% of the selachian fauna that has been identified in the studiedarea. The different distribution of the Carcharhiniformes (as well as that of the other orders) by the three sitespoints out to distinct environments in the corresponding areas: Esbarrondadoiro indicates relatively deeper, ratherstill waters; Santa Margarida…
New insights into the enameloid microstructure of batoid fishes (Chondrichthyes)
2016
Chondrichthyan teeth are capped with a hypermineralized tissue known as enameloid. Its microstructure displays a hierarchical organization that has increased in structural complexity from a homogenous single-crystallite enameloid (SCE) in early Chondricthyans to the complex multilayered enameloid found in modern sharks (consisting of bundles of crystallites arranged in intriguing patterns). Recent analyses of the enameloid microstructure in batoid fishes, focused on Myliobatiformes and fossil taxa, point to the presence of a bundled (or fibred) multilayered enameloid, a condition proposed as plesiomorphic for Batoidea. In this work, we provide further enameloid analysis for a selection of t…