Order Summary for Pleuronectiformes
Main Ref
:
Order
:
Pleuronectiformes flatfishes
Class
:
Teleostei
Sister Order
:
Tetraodontiformes 15 M years
Ref.
:
First Fossil Record
:
late Tertiary
Occurs in
:
Marine
Fresh
Brackish
Remark
:
Adults not bilaterally symmetrical, with one eye migrating to the other side of the cranium; dorsal and anal fins with long bases, dorsal fin base overlapping at least the neurocranium except in Psettodes; body highly compressed, somewhat rounded on eyed side and flat on blind side; eyes can protrude above body surface allowing fish to see when buried in the substrate; usually six or seven branchiostegal rays, rarely eight; body cavity small; adults almost always without swim bladder; scales cycloid, ctenoid, or tuberculate. About four species probably occur in freshwater, while another 20 species that are normally marine occasionally enter freshwater.
Class etymology
:
Greek aktis = ray, thunderbolt, beam + Greek pterygion, diminutive of pteryx = wing, fin. Ref. 45335.
Order etymology
:
Greek, pleura = similar, ribe, side + Greek, nektos = to swim + Latin, forma = shape. 1849 (Ref. 45335).
Families
:


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