This article about a prehistoric jawless fish is a stub.
You can help Wikipedia by expanding it.
The osteostracans reconstructed here belong to the major clade
Cornuata
, whose generalised morphology is exemplified by the
zenaspidid
Zenaspis
(bottom left). Some highly derived head-shield morphologies are exemplified by the
benneviaspidids
Hoelaspis
(top right) and
Tauraspis
(top left), or the
thyestiid
Tremataspis
(bottom right). The latter, of the family
Tremataspididae
, has lost the paired fins, possibly as a consequence of an adaptation to burrowing habits.
[
4
]