Meeksiella, a new ptyctodont placoderm from the Devonian of Estonia and Russia

[Halichoeres]

Ptyctodonts (not to be confused with pycnodonts) are a strange group of placoderms with reduced armor and a body plan similar to modern chimaeras, except instead of crushing teeth, they had crushing bony plates at the edges of their jaws. Some specimens from Estonia and Russia had been referred to Chelyophorus, but new specimens show that they represent a new genus, described here as Meeksiella pskovensis.

Here's a reconstruction of the head shield, the only major armor component that most ptyctodonts retained:


Lots more images in the paper, which is open access in Paleontologia Electronica: https://palaeo-electronica.org/content/2019/2490-a-new-baltic-ptyctodont