''Dicksonosteus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of basal arthrodire, placoderm fish, which lived during the Early Devonian period of

Spitsbergen Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norw ...

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

. ''Dicksonosteus'' was once considered an actinolepid, but is now grouped within the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Phlyctaeniidae Phlyctaeniidae is an extinct family of placoderm fishes that lived during the Devonian period, mainly in Norway and North America. Phylogeny ORDER ARTHRODIRA * Infraorder Actinolepina ** Family Actinolepidae * Suborder Phlyctaenioidei ** Famil ...

.Goujet, D. (1975). Dicksonosteus, un nouvel arthrodire du Dévonien du Spitsberg—Remarques sur le squelette viscéral des Dolichothoraci. ''Colloques internationaux du Centre National de la Recherche Scientifique'', 218, 81-99.

Description

''Dicksonosteus'' is considered basal to the

arthrodires Arthrodira (Greek for "jointed neck") is an order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ec ...

, the most successful and widespread group of placoderms during the

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

period notable for the movable joint between the armour sections surrounding their heads and bodies. Its body is wide and flat, and unlike the more robust-jawed arthrodires that would come after it, such as '' Dunkleosteus'' and ''

Coccosteus ''Coccosteus'' (from el, κόκκος , 'berry' and el, ὀστέον 'bone') is an extinct genus of arthrodire placoderm from the Devonian period. Its fossils have been found throughout Europe and North America. The majority of these have b ...

'', its jaws were relatively feeble, suggesting the lifestyle of a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

fish that subsisted primarily on smaller, softer-bodied animals. Exceptionally preserved

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

specimens of ''Dicksonosteus'' from

display details of its braincase and internal anatomy, the details of which have been described.^How?

References

Placoderms of Europe Phlyctaeniidae Fossils of Norway {{Placoderm-stub