Conversation so far:
What do art historians mean by animal style art?
Animal style art is an approach to decoration found from China to Northern Europe in the early Iron Age, and the barbarian art of the Migration Period
What did this mean to the people making the animal style art?
After Christianization, Migration Period art developed into various schools of Early Medieval art
What was the styles called after Migration Period art developed into various schools of art?
They're normally classified by region, such as Anglo-Saxon art and Carolingian art, before the continent-wide styles of Romanesque art and finally Gothic art developed.

Question: What are the origins of these
Self-contained rewrite: What are the origins of the two animal styles in Migration PEriod art?