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Elasmobranchii is one of the two subclasses of cartilaginous fish in the class Chondrichthyes, the other being Holocephali . Members of the elasmobranchii subclass have no swim bladders, five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins, and small placoid scales. The teeth are in several series; the ...
Many had hypocercal tails in order to generate lift to increase ease of movement through the water for their armoured bodies, which were covered in dermal bone. They also had sucking mouth parts and some species may have lived in fresh water. The taxon contains the subgroups Heterostraci, Astraspida, Arandaspida. † Thelodonti (extinct)
[3] [5] On average, males have 72 spine serrations and females have 66 spine serrations. The spine makes about 70% of the male's length and 65% of the female's length. [ 7 ] The mid dorsal groove, which contains the glandular tissue necessary for venom injection, extends along 10–40% the tail.
Gansuselache is a genus of extinct elasmobranch in the order Hybodontiformes, comprising one species, Gansuselache tungshengi from Gansu Province (Beishan Hills), China. [1] It is known from Fangshankou Formation , which previously interpreted as Permian in age, but reinterpreted as the Early Triassic in later study. [ 2 ]
Synechodontiformes (1 C, 2 P) X. Xenacanths (10 P) Pages in category "Elasmobranchii" The following 15 pages are in this category, out of 15 total.
30 Color Photos Photographers Took 100 Years Ago That Still Mesmerize Us Today. ... #1 Irish Spinner And Spinning Wheel. Co. Galway, Ireland, 1890 ... #20 Fingal's Cave, Staffa, Scotland.
Rainer Zangerl: Handbook of Paleoichthyology 3 A. Chondrichthyes I. Paleozoic Elasmobranchii. Gustav Fischer Verlag, New York 1981 (unveränderte Neuauflage Januar 2004) ISBN 3-89937-045-7 Rainer Zangerl and Gerard Ramon Case: Iniopterygia: a new order of Chondrichthyan fishes from the Pennsylvanian of North America.
The oldest members of the order appeared during the Middle-Late Jurassic, which have teeth and body forms that are morphologically similar to living catsharks. [1] Carchariniformes first underwent major diversification during the Late Cretaceous , initially as mostly small-sized forms, before radiating into medium and large body sizes during ...