Order Summary for Gymnotiformes
Main Ref
:
Order
:
Gymnotiformes knifefishes
Class
:
Teleostei
Sister Order
:
Siluriformes 150 M years
Ref.
:
First Fossil Record
:
late Miocene
Occurs in
:
Marine
Fresh
Brackish
Remark
:
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.
Class etymology
:
Greek aktis = ray, thunderbolt, beam + Greek pterygion, diminutive of pteryx = wing, fin. Ref. 45335.
Order etymology
:
Greek, gymnos = naked + Latin, forma = shape (Ref. 45335); ous or otos refers to opercle.
Families
:


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