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). 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. The typical tolypelepid had a carapace formed from dorsal and ventral plates, and a scaly tail.
left|thumb|[[Athenaegis|Athenaegis chattertoni cast, middle Silurian, Road River Formation, Mackenzie Mountains, Northwest Territories (Canada).]]
left|thumb|Athenaegis chattertoni reconstruction. At the [[Museo delle Scienze|Museo delle Scienze (MUSE). ]]