Buchanosteidae

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Buchanosteidae is a family of arthrodire placoderms that lived from the Early to Middle Devonian.[1] Fossils appear in various strata in Russia, Central Asia, Australia, and China.

Buchanosteidae
Temporal range: Lochkovian–Emsian
Buchanosteus confertituberculatus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Placodermi
Order: Arthrodira
Suborder: Brachythoraci
Family: Buchanosteidae
White, 1952
Type species
Phlyctaenaspis australis var. confertituberculata
Chapman, 1916
Genera
Synonyms
  • Goodradigbeeonidae
  • Taemasosteidae

All buchanosteids tend to have flattened (of varying degrees depending on the genus) heads, with most genera also having large orbits.[2]

Genera

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Arenipiscis

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From the Emsian of New South Wales, it is known from several scrappy remains. It had a narrow skull, and the dermal surfaces of the bony armor were covered in a pattern of fine, granular tubercles.

Buchanosteus

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The type genus, species are found in Emsian-aged strata in Australia, China, and Kazakhstan.

Burrinjucosteus

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A large buchanosteid from the Taemas-Weejasper Reef of Emsian-aged New South Wales, its skull roof suggests the living animal was fairly broad and flat.

Errolosteus

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One of several Taemas-Weejasper buchanosteid genera, Errolosteus had a comparatively broad, short skull.

Exutaspis

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A "giant" buchanosteid from Emsian-aged strata in China. The holotype, an endocranium, was originally described as that of a phlyctaeniid. The endocranium is several times larger than that of its sympatric relative, B. guangxiensis.

Goodradigbeeon

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A flattened buchanosteid from the Emsian Taemas-Weejasper Reef, it shares anatomical similarities with homostiids. Unlike the other Taemas-Weejasper buchanosteids, Goodradigbeeon is known from at least one mostly articulated specimen.

Narrominaspis

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A small, large-eyed stem buchanosteid, it is known from Late Lochkovian-aged strata of the Connemarra Formation in Central New South Wales.

Parabuchanosteus

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Another one of the Taemas-Weejasper Reef buchanosteids, Parabuchanosteus was originally described as a species of Buchanosteus, but was then promoted to its own genus due to differences in anatomy. The main difference between the two genera is that Parabuchanosteus has a somewhat shorter thoracic armor.

Taemasosteus

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An "advanced" New South Wales buchanosteid, it has various anatomical features found in other arthrodire groups, such as coccosteids and homostiids, but not with other buchanosteids.

Toombstosteus

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This genus is known from scrappy remains found in the Taemas-Weejasper Reef of Emsian New South Wales.

Uralosteus

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This genus is found in two Emsian-aged deposits in the Ural Mountains in the Autonomous Republic of Bashkortostan, Russia. The anatomy is similar, but distinct from other buchanosteids. The dermal surface of the armor has a unique pattern of crowded ridging.

References

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  1. ^ White, E. I. (1952). Australian arthrodires. Bulletin of the British Museum (Natural History) (Geology) 1: 249–304.
  2. '^ Denison, Robert (1978). Placodermi Volume 2 of Handbook of Paleoichthyology. Stuttgart New York: Gustav Fischer Verlag. p. 69. ISBN 978-0-89574-027-4.