Pachyosteus

Pachyosteus
Temporal range: Late Devonian, 382.7–359.3 Ma
Artist's reconstruction
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: †Placodermi
Order: †Arthrodira
Suborder: †Brachythoraci
Family: †Selenosteidae
Genus: †Pachyosteus
Jaekel, 1903
Species
  • Pachyosteus bulla Jaekel, 1903 (type)
Synonyms
Fossil on display at Geological Museum of the State Geological Institute in Warsaw, Poland

Pachyosteus is an extinct monospecific genus of medium-sized selenosteid arthrodire placoderm known from the Upper Frasnian Kellwasserkalk facies of Late Devonian Bad Wildungen, Germany and from the Famennian portions of the Holy Cross Mountains of Poland.[1] The type species Pachyosteus bulla has a broad skull about 7 to 10 centimetres (3 to 4 in) long, a comparatively long median dorsal plate, and a short rostral plate that meets the pineal plate.

Phylogeny

Pachyosteus is a member of the family Selenosteidae of the clade Aspinothoracidi, which belongs to the clade Pachyosteomorphi, one of the two major clades within Eubrachythoraci. The cladogram below shows the phylogeny of Pachyosteus:[2]

Eubrachythoraci 

In his cladogram, Rücklin (2011) regards Pachyosteus bulla as a basal selenosteid, being the sister taxon of the American genera, and the Kellwasserkalk genera of Germany and Morocco.[3]

Aspinothoracidi

References

  1. ^ Denison, Robert (1978). Handbook of Paleoichthyology, Volume 2, Placodermi. New York: Gustav Fischer Verlage. p. 94. ISBN 9780895740274.
  2. ^ Zhu, You-An; Zhu, Min; Wang, Jun-Qing (1 April 2016). "Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci". Zoological Journal of the Linnean Society. 176 (4): 806–834. doi:10.1111/zoj.12356. ISSN 0024-4082.
  3. ^ RÜCKLIN, MARTIN (January 14, 2011). "First selenosteid placoderms from the eastern Anti-Atlas of Morocco; osteology, phylogeny and palaeogeographical implications". Palaeontology. 56 (1): 25–62. doi:10.1111/j.1475-4983.2010.01026.x.


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