Anaspida

Anaspida; Temporal range: early Silurian - Late Devonian
	Cowielepis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Superclass:	†Anaspidomorphi
Class:	†Anaspida; Traquair, 1899
Type species
	†Birkenia elegans; Traquair 1898
Orders
	Endeiolepidiformes; Birkeniiformes;
Synonyms
	Anaspidi; Birkeniae;

Anaspids are characterized by a large, tri-radiate spine (red) posteriorly to the series of branchial openings. It is assumed that the most primitive anaspids, such as *Pharyngolepis* (top), possessed a long, ribbon-shaped, ventrolateral fin-fold (green). More advanced forms, such as *Rhyncholepis* (bottom), possessed a shorter paired fin-fold (green) and enlarged, spine-shaped, median dorsal scutes. – Philippe Janvier^[1]

Anaspida ("shieldless ones") is an extinct group of jawless fish that existed from the early Silurian period to the late Devonian period.^[2] They were classically regarded as the ancestors of lampreys,^[3] but it is denied in recent phylogenetic analysis,^[4] although some analysis show these group would be at least related.^[5] Anaspids were small marine fish that lacked a heavy bony shield and paired fins, but were distinctively hypocercal.

^ Janvier, Philippe (1997) Anaspida The Tree of Life Web Project.
^ Ahlberg, Per Erik (2001). Major events in early vertebrate evolution: palaeontology, phylogeny, genetics, and development. Washington, DC: Taylor & Francis. p. 188. ISBN 0-415-23370-4.
^ Patterson, Colin (1987). Molecules and morphology in evolution: conflict or compromise?. Cambridge, UK: Cambridge University Press. p. 142. ISBN 0-521-32271-5.
^ Keating, Joseph N.; Donoghue, Philip C. J. (2016-03-16). "Histology and affinity of anaspids, and the early evolution of the vertebrate dermal skeleton". Proceedings of the Royal Society B: Biological Sciences. 283 (1826): 20152917. doi:10.1098/rspb.2015.2917. ISSN 0962-8452. PMC 4810860.
^ Cite error: The named reference :0 was invoked but never defined (see the help page).

[Janvier1997-1] Janvier, Philippe (1997) Anaspida The Tree of Life Web Project.

[isbn0-415-23370-4-2] Ahlberg, Per Erik (2001). Major events in early vertebrate evolution: palaeontology, phylogeny, genetics, and development. Washington, DC: Taylor & Francis. p. 188. ISBN 0-415-23370-4.

[isbn0-521-32271-5-3] Patterson, Colin (1987). Molecules and morphology in evolution: conflict or compromise?. Cambridge, UK: Cambridge University Press. p. 142. ISBN 0-521-32271-5.

[4] Keating, Joseph N.; Donoghue, Philip C. J. (2016-03-16). "Histology and affinity of anaspids, and the early evolution of the vertebrate dermal skeleton". Proceedings of the Royal Society B: Biological Sciences. 283 (1826): 20152917. doi:10.1098/rspb.2015.2917. ISSN 0962-8452. PMC 4810860.

[:0-5] Cite error: The named reference :0 was invoked but never defined (see the help page).

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Anaspida Temporal range: early Silurian - Late Devonian

Cowielepis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Superclass:	†Anaspidomorphi
Class:	†Anaspida Traquair, 1899
Type species
†Birkenia elegans Traquair 1898
Orders
Endeiolepidiformes Birkeniiformes
Synonyms
Anaspidi Birkeniae