Tolypelepidida

Tolypelepidida is an extinct order of heterostracan vertebrates. These armored jawless fish superficially resemble their relatives, the cyathaspids, though, researchers place the tolypelepids as a sister group to the cyathaspids and the pteraspidids (and both groups' daughter taxa).^[1] A recent study by Lundgren and Blom in 2013 implies that the order is paraphyletic, with the type genus, Tolypelepis, being the sister taxon of Cyathaspidiformes.^[2] The typical tolypelepid had a carapace formed from dorsal and ventral plates, and a scaly tail.

Athenaegis chattertoni cast, middle Silurian, Road River Formation, Mackenzie Mountains, Northwest Territories (Canada).

Athenaegis chattertoni reconstruction. At the Museo delle Scienze (MUSE).

Tolypelepidida Temporal range: Silurian - Early Devonian
The type species, Tolypelepis undulata
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Infraphylum:	Agnatha
Class:	†Pteraspidomorpha
Subclass:	†Heterostraci
Order:	†Tolypelepidida Denison 1964
Family:	†Tolypelepididae Kiær 1932
Genera
Asketaspis Athenaegis Tolypelepis
Synonyms
Tolypelepidiformes