''Auchenaspis salteri'' is an extinct species of armored jawless fish of the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Thyestiida Thyestiida is an order of bony-armored jawless fish in the extinct vertebrate class Osteostraci The class Osteostraci (meaning "bony shells") is an extinct taxon of bony-armored jawless fish, termed " ostracoderms", that lived in what is now ...

from the Late

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. In England, ''A. salteri'''s fossils are found in extreme abundance in the Lower Old Red Sandstone strata in

Ledbury Ledbury is a market town and civil parish in the county of Herefordshire, England, lying east of Hereford, and west of the Malvern Hills. It has a significant number of Tudor style timber-framed structures, in particular along Church Lane a ...

Herefordshire Herefordshire ( ) is a Ceremonial counties of England, ceremonial county in the West Midlands (region), West Midlands of England, bordered by Shropshire to the north, Worcestershire to the east, Gloucestershire to the south-east, and the Welsh ...

. ''A. salteri'' strongly resembles the thyestiids '' Procephalaspis'' and ''

Thyestes In Greek mythology, Thyestes (pronounced , , ) was a king of Olympia. Thyestes and his brother, Atreus, were exiled by their father for having murdered their half-brother, Chrysippus, in their desire for the throne of Olympia. They took refuge ...

'', and within Thyestiida, it represents a transitional form between the primitive, superficially ''

Cephalaspis ''Cephalaspis'' (from , 'head' and , 'shield') is a possibly monotypic genus of extinct osteostracan agnathan vertebrate. It was a trout-sized detritivorous fish that lived in the early Devonian. Description Like its relatives, ''Cephalaspi ...

''-like forms, such as ''Thyestes'', and the more specialized tremataspid thyestiids, like ''

Tremataspis ''Tremataspis'' is a genus of an extinct osteostracan agnathan from the Silurian period of what is now Estonia. ''Tremataspis'' was about in length, and had an armored shield covering its head. Compared with its relatives, the shield was unus ...

'', '' Dartmuthia'', or '' Dobraspis'', whose headshields tend to resemble hot buns or horseshoe crabs.

References

Osteostraci genera Silurian fish of Europe Fossils of Great Britain {{Paleo-jawless-fish-stub