Wikipedia
Ptycholepis
Ptycholepis is an extinct genus of prehistoric ray-finned fish having the head and opercular bones ornamented with ridges of ganoin, minute teeth, and thick scales (which are much longer than deep and are grooved longitudinally on the outer side).
bollensis.jpg|Ptycholepis bollensis bollensis - Holzmaden.jpg|Ptycholepis bollensis bollensis - Lyme Regis.jpg|Ptycholepis