fishlike vertebrate with bony plates on head and upper body; dominant in seas and rivers during the Devonian; considered the earliest vertebrate with jaws.

• 头部和身体上方有骨片的似鱼的脊椎动物；泥盆纪时期海中和河中的优势物种；曾被认为是最早的有颚脊椎动物。