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Related to Chondrichthyes: class Chondrichthyes


A class of vertebrates comprising the cartilaginous, jawed fishes. The Chondrichthyes have traditionally included the subclasses Elasmobranchii (sharks, skates, and rays) and Holocephali (ratfishes). A classification scheme for the Chondrichthyes follows.

  • Class Chondrichthyes
  • Subclass Elasmobranchii
  • Order: Cladoselachii
  • Pleurocanthodii
  • Selachii
  • Batoidea
  • Subclass Holocephali
  • Order Chimaeriformes

A group of Devonian armored fishes, the Placodermi, has usually been regarded as ancestral to the Chondrichthyes, but this derivation is not certain. Another group of primitive jawed fishes called acanthodians, which are considered by many as ancestral to the higher bony fishes, exhibit certain primitive elasmobranch-like features. In any case it is probable that the elasmobranchs and ratfishes arose independently of each other sometime during the Silurian or Early Devonian. See Acanthodii, Placodermi

The most distinctive feature shared by the elasmobranchs and ratfishes is the absence of true bone. In both groups the endoskeleton is cartilaginous; in some cases it may be extensively calcified. Because even calcified cartilage is rarely preserved, the fossil record of the Chondrichthyes is represented mainly by teeth and spines, with only occasional associated skeletons.

Other characteristics of the Chondrichthyes include placoid scales, clasper organs on the pelvic fins of males for internal fertilization, a urea-retention mechanism, and the absence of an air (swim) bladder. Both groups have primarily always been marine predators, although they have repeatedly invaded fresh water throughout their long history. The elasmobranchs have probably always fed as they do today, on other fishes as well as on soft and hard-bodied invertebrates. The ratfishes have most likely concentrated on invertebrates, although modern forms occasionally also feed on smaller fishes. See Ray, Swim bladder

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a class of fishes that includes two subclasses: Elasmobranchii and Holocephali. The fish have a cartilaginous skeleton fortified by calcification. The scales are placoid. There is a spiral valve in the intestine and an arterial cone in the heart. Many Chondrichthyes have a cloaca. In Elasmobranchii the skull is hyostylic (with a single articulation of the jaw with the skull) or amphistylic (with two such articulations). In Holocephali the skull is autostylic (with the jaw concresced with the skull). In almost all Chondrichthyes insemination is apparently internal. Males have a special copulatory organ, the pterygopodium, which is formed from rays of the ventral fins.

The Chondrichthyes are viviparous or oviparous. The majority are predators. They are predominantly marine fish; only a few Elasmobranchii have adapted to freshwater life. Fossil Chondrichthyes are known from the Devonian.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


(vertebrate zoology)
A class of vertebrates comprising the cartilaginous, jawed fishes characterized by the absence of true bone.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
(Chondrichthyes) from the Burtnieki Regional Stage, Middle Devonian of Estonia.
Parametros hematolOgicos, aspectos citoquimicos e ultraestruturais das celulas sanguineas de tres especies de arraias de Agua doce (Chondrichthyes: Potamotrygonidae) do Arquipelago deMariuA, Amazonas.
Although some of these paralogs tandemly duplicated within the teleost lineage, others including aqp3, -3L, -8aa, -8ab, -10, and -10L duplicated earlier in Chondrichthyes or prior to the separation of Holostei from Teleostei (Finn et al., 2014).
?Es Posible Criar Tiburones?: El Caso de la Pintarroja Comun, Schroederichthys chilensis (Chondrichthyes, Scyliorhinidae).
The exceptions are Rhodophyta, Dinoflagellata, Chondrichthyes, Oomycota, Rhizaria, and Annelida.
A checklist of Neoselachii (Pisces, Chondrichthyes) from the Palaeogene of the Paris Basin, France.
Summers, "Feeding mechanism and functional morphology of the jaws of the lemon shark Negaprion brevirostris (Chondrichthyes, Carcharhinidae)," Journal of Experimental Biology, vol.