Coccosteidae is a

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 ...

arthrodire Arthrodira (Greek for "jointed neck") is an Order (biology), 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 penetratin ...

placoderms from the Early to Late

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 ...

. Fossils appear in various strata in Europe, North America and China.

Phylogeny

Coccosteidae belongs to the larger

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

Coccosteomorphi Coccosteomorphi is an extinct clade of arthrodire placoderms within the Eubrachythoraci (of the suborder Brachythoraci), armored fish most diverse during the Devonian. Most are considered to be pelagic (open ocean) long-distance swimmers, leadin ...

, which together with its

sister clade In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

Pachyosteomorphi Pachyosteomorphi is an extinct clade of arthrodire placoderms within the Eubrachythoraci (of the suborder Brachythoraci), armored fish most diverse during the Devonian. Most are considered to be pelagic (open ocean) long-distance swimmers, leadi ...

forms the group

Eubrachythoraci Eubrachythoraci is an extinct clade of arthrodire placoderms within the suborder Brachythoraci, armored fish most diverse during the Devonian. Most are considered to be pelagic (open ocean) long-distance swimmers, leading to their widespread dis ...

. The

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

of Coccosteidae can be shown in the

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

below:

Genera

'' Belgiosteus''

A genus of very large coccosteids. Species are found in

Middle 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, wher ...

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

and

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

'' Clarkosteus''

''
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 ...
''

The

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal f ...

of the family. Numerous species are found in Middle to Upper Devonian strata throughout Europe and parts of North America.

''
Dickosteus ''Dickosteus'' is an extinct genus of coccosteid arthrodire placoderm from the Late Eifelian to Early Givetian stages of the Middle Devonian period. Fossils are found in the Orkneys and Caithness, Scotland. Phylogeny ''Dickosteus'' is a member o ...
''

''
Jiuchengia ''Jiuchengia longoccipita'' is a coccosteid arthrodire placoderm from the Late Emsian epoch of Wuding, Yunnan Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and ...
''

The earliest known coccosteid from

Late Emsian 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, wher ...

Yunnan province Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the C ...

, China. It is distinguished from other coccosteids by having an elongated

occipital The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cereb ...

'' Livosteus''

A genus of very large coccosteids known from Middle to Late Devonian strata of Eastern Europe.

''
Millerosteus ''Millerosteus'' is an extinct genus of coccosteid arthrodire placoderm from the Early Givetian stage of the Middle Devonian period. Fossils are found in the Orkneys and Caithness, Scotland. Phylogeny ''Millerosteus'' is a member of the family C ...
''

A genus of very small coccosteids known from Middle to Late Devonian strata throughout Europe. Some species are found in the same strata with certain species of ''

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 ...

''.

''
Protitanichthys ''Protitanichthys'' is an extinct genus of comparatively large coccosteid arthrodire placoderms from the Middle Devonian of the eastern United States. Fossils are found primarily in the Eifelian-epoch aged Delaware Limestone of Ohio, and the Lowe ...
''

''
Watsonosteus ''Watsonosteus'' is an extinct genus of coccosteid arthrodire placoderm from the Late Givetian stage of the Middle Devonian period. Fossils are found in the Orkney Islands, Scotland. Phylogeny ''Watsonosteus'' is a member of the family Coccostei ...
''

'' Woodwardosteus''

References

{{Taxonbar, from=Q16980853

Phylogeny

Genera

'' Belgiosteus''

'' Clarkosteus''

''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 ...''

''Dickosteus ''Dickosteus'' is an extinct genus of coccosteid arthrodire placoderm from the Late Eifelian to Early Givetian stages of the Middle Devonian period. Fossils are found in the Orkneys and Caithness, Scotland. Phylogeny ''Dickosteus'' is a member o ...''

''Jiuchengia ''Jiuchengia longoccipita'' is a coccosteid arthrodire placoderm from the Late Emsian epoch of Wuding, Yunnan Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and ...''