Acastina Acaste is a genus of extinct trilobite of the order Phacopida which lived throughout the Silurian period (Wenlock Group).

[1] Though many species had been included, it now has only one species, Acaste downingiae.

[2] It is characterized by a convex dorsal surface, an absence of spines, a shortening of the head-shield and a general rounding off of all angles.

[3] Some species originally designated to Acaste have now been reassigned to other genera.

This Phacopida-related article is a stub.