''Acastocephala'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...

s from the middle

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 ...

, known from the United Kingdom.

Etymology

The name is derived from the genus ''Acaste'' and the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

κεφαλή (kephalē) "head", indicating the headshield is similar to ''Acaste''.

Taxonomy

''Acastocephala'' may contain the ancestor of '' Acastava''.

Distribution

* ''Acastocephala macrops'' occurs in the Middle Silurian of the United Kingdom (

Wenlock Shale The Buildwas Formation (''Bw'', ''BUI''), formerly called Wenlock Shale and Buildwas Beds, is a geologic formation in Shropshire, England. It preserves fossils dating back to the Silurian period. The formation is the defining formation of the Sh ...

Malvern, Worcestershire Malvern (, locally also: ) is a spa town and Civil parishes in England, civil parish in Worcestershire, England. It lies at the foot of the Malvern Hills, a designated Area of Outstanding Natural Beauty. The centre of Malvern, Great Malvern, is ...

; Wenlock Limestone, Pen-y-Lan, Cardiff, and

Dudley Dudley ( , ) is a market town in the West Midlands, England, southeast of Wolverhampton and northwest of Birmingham. Historically part of Worcestershire, the town is the administrative centre of the Metropolitan Borough of Dudley. In the ...

and Ludlow,

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 ...

, Hereford). * ''Acastocephala dudleyensis'' has been found in the Middle Silurian of the United Kingdom (Wenlock Limestone,

Wren's Nest The Wren's Nest is a geological Site of Special Scientific Interest in the Dudley Metropolitan Borough, north west of the town centre of Dudley, in the West Midlands of England. It is one of the most important geological locations in Britain. ...

, Dudley, Worcestershire).

References

External links

Wenlock Trilobite ''Acastocephala'' - Fossilmuseum.net
Acastidae Silurian trilobites of Europe Fossils of Great Britain Fossils of England Fossils of Wales Phacopida genera {{phacopida-stub