Boreaspis

Boreaspis (meaning "Boreas' Shield") is an extinct genus of osteostracan agnathan vertebrate that lived in the Devonian period.

Boreaspis
Temporal range: Pragian–Emsian
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: †Osteostraci
Order: †Benneviaspidida
Family: †Boreaspididae
Genus: †Boreaspis
Stensio, 1927
Species
  • B. rostrata Stensio, 1927 (type)
  • B. batoides Wangsjo, 1952
  • B. macrorhynchus Wangsjo, 1952
  • B. puella Wangsjo, 1952
  • B. spinicornis Wangsjo, 1952
  • B. triangularis Wangsjo, 1952
  • "B." ceratops Wangsjo, 1952
  • "B." intermedia Wangsjo, 1952

Fourteen different species of Boreaspis have been found in sandstone of the lagoons and estuaries of Devonian Spitsbergen; however, some of these likely do not belong to the genus.[1] The species B. robusta and B. costata have been reassigned to Spatulaspis; and B. circinus, B. curtirostris, and B. gracilis now belong to Dicranaspis.[2]

Species of Boreaspis were very small, with head shields about 2 centimetres (0.79 in) long.[3] All species possessed a long spathe-like rostrum derived from the anterior-most end of the head shield, which would have enhanced the fish's hydrodynamics and was probably also used to root out food buried beneath the substrate.[4]

References
  1. Sansom, R.S. (2009). "Phylogeny, classification and character polarity of the Osteostraci (Vertebrata)". Journal of Systematic Palaeontology. 7 (1): 95–115. doi:10.1017/S1477201908002551.
  2. Groh, S. "Appendix". Patterns of diversification in osteostracan evolution (PDF) (M.S.). Uppsala University.
  3. Frickhinger, Karl Albert (1995). Fossil Atlas: Fishes. Trans. Dr. R.P.S. Jefferies. Blacksburg, Virginia: Tetra Press.
  4. Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 25. ISBN 978-1-84028-152-1.
  • Long, John A. (1996). The Rise of Fishes: 500 Million Years of Evolution. Baltimore: The Johns Hopkins University Press. ISBN 978-0-8018-5438-5.


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