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Some characteristics previously thought to be exclusive to acanthodians are also present in basal cartilaginous fish. [18] In particular, new phylogenetic studies find cartilaginous fish to be well nested among acanthodians, with Doliodus and Tamiobatis being the closest relatives to Chondrichthyes. [19]
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 ...
The following is the full list of the extant species in Class Chondrichthyes, or the cartilaginous fish. Members of this class have a backbone , gills , no swim bladder , jaws , and a skeleton made of cartilage , a soft, strong material as a replacement for bone .
Batomorphi is a clade of cartilaginous fishes, commonly known as rays, this taxon is also known as the superorder Batoidea, but the 5th edition of Fishes of the World classifies it as the division Batomorphi. [2] They and their close relatives, the sharks, compose the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes ...
Skates are cartilaginous fish belonging to the family Rajidae in the superorder Batoidea of rays.More than 150 species have been described, in 17 genera. [2] Softnose skates and pygmy skates were previously treated as subfamilies of Rajidae (Arhynchobatinae and Gurgesiellinae), but are now considered as distinct families. [2]
Chimaeras are soft-bodied, shark-like fish with bulky heads and long, tapered tails; measured from the tail, they can grow up to 150 cm (4.9 ft) in length. Like other members of the class Chondrichthyes, chimaera skeletons are entirely cartilaginous, or composed of cartilage.
Some sources extend the term "shark" as an informal category including extinct members of Chondrichthyes (cartilaginous fish) with a shark-like morphology, such as hybodonts. Shark-like chondrichthyans such as Cladoselache and Doliodus first appeared in the Devonian Period (419–359 million years), though some fossilized chondrichthyan-like ...
Cartilaginous fish (sharks and rays) have a more advanced immune system. They have three specialized organs that are unique to chondrichthyes; the epigonal organs (lymphoid tissues similar to mammalian bone) that surround the gonads, the Leydig's organ within the walls of their esophagus, and a spiral valve in their intestine. These organs ...