Buchanosteidae is a family of

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 ...

placoderm Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos'''Plate (animal anatomy), plate' and δέρμα 'derma'''skin') are vertebrate animals of the class (biology), class Placodermi, an extinct group of prehistoric fish known from Pal ...

s that lived from the Early to Middle

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

.White, E. I. (1952). Australian arthrodires. ''Bulletin of the British Museum (Natural History) (Geology)'' 1: 249–304. Fossils appear in various strata in Russia, Central Asia, Australia, and China. All buchanosteids tend to have flattened (of varying degrees depending on the genus) heads, with most genera also having large orbits.

Genera

''Arenipiscis''

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''

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

''Burrinjucosteus''

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''

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

''Exutaspis''

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 In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

relative, ''B. guangxiensis''.

''Goodradigbeeon''

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''

A small, large-eyed

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

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

''Parabuchanosteus''

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''

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''

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

''Uralosteus''

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

Placoderm families {{placoderm-stub