Order Summary for Cyprinodontiformes

  Main Ref
:
  Order
:
Cyprinodontiformes rivulines, killifishes and live bearers
  Class
:
Actinopterygii
  Sister Order
:
Beloniformes 45 M years
  Ref..
:
  First Fossil Record
:
early Tertiary
  Occurs in
:
Marine
Fresh
Brackish
  Remark
:
Monophyly of this order is recognized on the basis of several derived characters: e.g., caudal fin symmetrical, supported internally by one epural; first pleural rib on second vertebrae rather than third; primitively, low-set pectoral girdle with a scalelike postcleithrum; an alveolar arm of the premaxillae; extended developmental period. In addition, they possess the following characters: lateral line canal and pores chiefly on head, lateral line represented on body only by pitted scales; narial opening paired; branchiostegal rays 3-7; pelvic fins and girdle present or absent; upper jaw bordered by premaxilla only, protrusible; vomer usually present and supracleithrum always present; metapterygoid usually absent and ectopterygoid always absent; parietals present or absent; vertebrae 24-54. Marked sexual dimorphism with the males often brightly colored.
  Classetymology
:
Greek aktis = ray, thunderbolt, beam + Greek pterygion, diminutive of pteryx = wing, fin. Ref. 45335.
  Orderetymology
:
Greek, kyprinos = goldfish + Greek, odous = tooth, teeth + Latin, forma = shape (Ref. 45335).
  Families
: