Elasmobranchii


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Elasmobranchii

[ə‚laz·mə′braŋ·kē‚ī]
(vertebrate zoology)
The sharks and rays, a subclass of the class Chondrichthyes distinguished by separate gill openings, amphistylic or hyostylic jaw suspension, and ampullae of Lorenzini in the head region.

Elasmobranchii

 

a subclass of cartilaginous fishes. The skeleton is cartilaginous and often calcified. The body is covered with placoid scales or, sometimes, is naked. The gills are lamellar. There is no gill cover; five to seven pairs of gill clefts open directly to the exterior. The mouth is inferior. The intestine has a spiral fold and opens into the cloaca. In males the terminal rays of the ventral fins are converted into copulatory organs, or pterygopodia. The subclass comprises two extinct orders and one extant order, the Selachii, which includes sharks (three suborders) and rays. Elasmobranchii first appeared in the Devonian. Most of the fishes inhabit seas; a few are encountered in fresh waters.

References in periodicals archive ?
Listado anotado de los tiburones, rayas y quimeras (Chondrichthyes: Elasmobranchii, Holocephali) de Mexico.
Although it is difficult to precisely quantify individual shark numbers from vertebrae and teeth (there can be >100 vertebrae per shark), there is almost an order of magnitude shift in Elasmobranchii vertebrae from the Archaic (n=35) to the Classic period (n=307).
Phase Totals Taxon 4 3 2 1 Count Percent Elasmobranchii (sharks and rays) 2 1 3 3 Myliobatidiformes 1 1 1 Scaridae (parrotfish) 3 18 5 26 28 Scaridae/Tetraodontidae 1 1 1 Tetraodontidae (puffers) 3 5 1 9 10 Unknown A 1 2 10 2 15 16 Unknown B 1 1 1 Unknown C 3 12 1 16 17 Unknown D 1 1 1 Unidentified post-cranial bones 5 11 5 21 22 Total 1 18 61 14 94 100 Table 5.
Deynat PP (1998) Le revetement cutane des raes (Chondrichthyes, Elasmobranchii, Batoidea).
Clase CHONDRICTHYES Huxley, 1880 Subclase ELASMOBRANCHII, Bonaparte, 1838 Cohorte EUSELACHII Hay, 1902 Superorden GALEOMORPHII Compagno, 1973
Crustacea Blue crab (Callinectes sapidus) Mantis shrimp (Squilla empusa) Elasmobranchii primarily skates (Raja spp.