Buchanosteidae

Buchanosteidae Temporal range: Lochkovian–Emsian PreꞒ Ꞓ O S D C P T J K Pg N
Buchanosteus confertituberculatus
Scientific 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
Arenipiscis Buchanosteus Burrinjucosteus Errolosteus Exutaspis Goodradigbeeon Narrominaspis Parabuchanosteus Taemasosteus Toombsosteus Uralosteus
Synonyms
Goodradigbeeonidae Taemasosteidae

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.

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

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 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 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

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.