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Temporal range: Late Frasnian to Famennian[1]
Pachyosteus bulla.jpg
Fossil on display
Pachyosteus bulla reconstruction.jpg
Artist's reconstruction
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Placodermi
Order: Arthrodira
Suborder: Brachythoraci
Infraorder: Coccosteina
Superfamily: Dinichthyloidea
Family: Selenosteidae
Genus: Pachyosteus
Species: P. bulla
Binomial name
Pachyosteus bulla
Jaekel 1903

Pachyosteus bulla is a 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. P. 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. In his cladogram, Rücklin (2011) regards P. bulla as a basal selenosteid, being the sister taxon of the American genera, and the Kellwasserkalk genera of Germany and Morocco.[2]


  1. ^ Denison, Robert (1978). Handbook of Paleoichthyology, Volume 2, Placodermi. New York: Gustav Fischer Verlage. p. 94. ISBN 9780895740274. 
  2. ^ 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.