A well-preserved ‘placoderm’ (stem-group Gnathostomata) upper jaw from the Early Devonian of Mongolia clarifies jaw evolution
https://commons.wikimedia.org/wiki/File:A_well-preserved_%E2%80%98placoderm%E2%80%99_(stem-group_Gnathostomata)_upper_jaw_from_the_Early_Devonian_of_Mongolia_clarifies_jaw_evolution.pdf
Gnathostomata) upper jaw from the Early Devonian of Mongolia clarifies jaw evolution.pdf English: Brazeau, Martin D.; Yuan, Haobo; Giles, Sam; Jerve, Anna