Belemnacanthus

Belemnacanthus Temporal range: Givetian
B. giganteus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Placodermi
Order:	Arthrodira
Family:	Holonematidae
Genus:	Belemnacanthus
Species:	B. giganteus
Binomial name
Belemnacanthus giganteus Eastman, 1898

Belemnacanthus giganteus ("Gigantic arrow-spine") is a large, extinct, barrel-shaped holonematid arthrodire placoderm from Givetian-aged strata of Middle Devonian Eifel, Germany. B. giganteus is known only from the holotype, a 37 centimetres (15 in) portion of a median dorsal plate with a long, somewhat high, arching crest running down the median line of the exterior/dorsal side of the plate. The plate has an ornamentation of ridges that originate from a point posterior to the preserved portion of the median dorsal plate. Before the plate was identified as that of a holonematid, the plate of B. giganteus had been successively described as a tremendous spine of an elasmobranch, an agnathan, and lastly, the plate of an antiarch.[1]

References

1. Denison, Robert (1978). Placodermi Volume 2 of Handbook of Paleoichthyology. Stuttgart New York: Gustav Fischer Verlag. p. 60. ISBN 978-0-89574-027-4.