The very first gnathostome -LRB- jawed fish -RRB- appeared in the Late Ordovician epoch .
The very first Gnathostomata -LRB- jawed fish -RRB- -RRB- appeared in the Upper Ordovician .
The very first Gnathostomata -LRB- jawed fish -RRB- -RRB- appeared in the Upper Ordovician .
단순화를 위해 이 문장을 다시 작성하십시오: The very first gnathostome -LRB- jawed fish -RRB- appeared in the Late Ordovician epoch . 산출: