1) Devonian animal
Found on
https://www.crosswordclues.com/clue/acleistoceras
Acleistoceras is a genus of the oncocerid, nautiloid family Acleistoceratidae that lived in the shallow seas that covered much of North America during the Devonian; living from 409—383.7 mya, existing for approximately {Mya|409-383.7|million years}. ==Taxonomy== Acleistoceras was named by Hyatt (1884) and assigned by Flower (1950) to the newly e...
Found on
http://en.wikipedia.org/wiki/Acleistoceras
No exact match found.
