初始全颌鱼 / Entelognathus primordialis

Your jaw has a deep backstory: my fossil combines ancient armour with surprisingly familiar face bones!
你的下巴来头不小：我的化石把古老铠甲和有些熟悉的脸部骨头组合在了一起！

Sources
A Silurian placoderm with osteichthyan-like marginal jaw bones
https://www.nature.com/articles/nature12617
A Silurian maxillate placoderm illuminates jaw evolution.
https://www.science.org/doi/10.1126/science.aah3764
Species reference
https://en.wikipedia.org/w/index.php?title=Entelognathus

Research context
Entelognathus combines placoderm-like armor with marginal jaw bones resembling those of bony fishes. It reshaped hypotheses about the ancestral jaw skeleton inherited by later bony vertebrates, including humans.