User:Abyssal/Portal:Silurian/DYK/3
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- ...that ostracoderms are the earliest known vertebrate animals?
- ... that fossils of the extinct bivalve family Praenuculidae have been found on every continent except Antarctica?
- ... that Arthropleuridea is an extinct class of myriapods which includes, at over 2 meters long, the largest terrestrial arthropods that ever lived?