Semionotus - A Triassic Semionotid.


Neopterygian node B: Presence of median neural spines, quadratojugal fused with quadrate or lost.


The semionotidae includes 25 genera of small active predatory fish with symmetrical, nearly entirely ray-supported tails and large dorsal and ventral fins. These possessed projecting maxilla and dentary lined with small sharp teeth. Semionotids such as the Semionotus above are especially well represented in the Newark Group Lakes (Late Triassic - Early Cretaceous) of North Eastern America were a probable flocking behaviour (indicated by the large number of individuals preserved in close proximity) appears to have been preserved for these fish.

The semionotids are possible relatives of the dapediids.