Lepidaspis

Lepidaspis serrata ("serrated scaly shield") is an extinct heterostracan jawless fish from Early Devonian Canada. Its scientific name refers to the fact that the armor is composed of hundreds of tiny scales with serrated edges.

Lepidaspis Temporal range:
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Infraphylum:	Agnatha
Class:	†Pteraspidomorphi
Subclass:	†Heterostraci
Order:	†Lepidaspidiformes
Family:	†Lepidaspididae
Genus:	†Lepidaspis Dineley & Loeffler 1976
Species
L. serrata Dineley & Loeffler 1976

Lepidaspis serrata cast. Mackenzie Mountains, Northwest Territories (Canada). At the Royal Tyrrell Museum of Palaeontology.

Although it is regarded as a heterostracan, its exact placement within Heterostraci is regarded as incertae sedis, as the fact that it is currently impossible to discern where its dorsal and ventral plates (which are made up of a mosaic of the aforementioned tiny scales) end or begin. Some experts regard it as being descended from the basal heterostracans of the Silurian.