Vertebrata (spinal cord, backbone, gill slits, postanal tail)

Petromyzontida
Lamprey

Conodonta
Conodont

Anaspida
Jamoytius kerwoodi

Pteraspidomorphi


Thelodonti


Galeaspida
Polybranchiaspis liaojaoensis

Pituriaspida
Pituriaspis

Osteostraci
Ostracodermii