Ordre Résumé for Gymnotiformes

  Réf. Princ.
:
  Ordre
:
Gymnotiformes knifefishes
  Classe
:
Actinopterygii
  Ordre frère
:
Siluriformes 150 M years
  Réf..
:
  Premier signalement fossile
:
late Miocene
  Présent dans
:
Marin
Eau douce
Saumâtre
  Remarque
:
Body eel-like (compressed or rounded); pelvic girdle and fins absent; dorsal fin absent; anal fin extremely long (more than 140 rays and extending from near pectoral fin origin to near tip of body) and employed in forward and backward movements; caudal fin absent or greatly reduced; restricted gill openings; anal opening under head or pectorals; basal pterygiophores to anal fin with only one section (radial) and a hemispherical cartilaginous head that articulates the fin rays (allowing them to move in a circular motion); electric organs present; suboperculum absent; palatine not ossified; maxilla rudimentary.
  ClasseÉtymologie
:
Greek aktis = ray, thunderbolt, beam + Greek pterygion, diminutive of pteryx = wing, fin. Ref. 45335.
  OrdreÉtymologie
:
Greek, gymnos = naked + Latin, forma = shape (Ref. 45335); ous or otos refers to opercle.
  Familles
:

Ref.
[ e.g. 9948]                       
Glossary
                    [ e.g. cephalopods]

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