''Balizoma'' is a genus of

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 family

Encrinuridae Encrinuridae is a family of trilobite within the order Phacopida that lived in what would be Africa, Asia, Australia, Europe, North America, and South America from the middle Ordovician to the early Devonian from , existing for approximately 66.7 ...

established by David J. Holloway in 1980. It has only been found in rocks of

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 ...

age. Its

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, ''B. variolaris'' (Brongniart, 1822), is currently the only named species of the genus, and is found in

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 ...

. The neotype of ''B. variolaris'' was collected from the

Much Wenlock Limestone Formation The Much Wenlock Limestone Formation is a series of Silurian limestone beds that date back to the Homerian age, the later part of the Wenlock epoch.{{cite web , url=http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=WEL , title=Much Wenlock Limeston ...

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 ...

, West Midlands. That specimen was first illustrated in Sir

Roderick Impey Murchison Sir Roderick Impey Murchison, 1st Baronet (19 February 1792 – 22 October 1871) was a Scottish geologist who served as director-general of the British Geological Survey from 1855 until his death in 1871. He is noted for investigating and desc ...

's classic book, '' The Silurian System''. ''B. variolaris'' was the original "strawberry-headed" trilobite of Dudley, so-named because of its nodular glabellar tubercles, and well known to early trilobite collectors. Additional species were originally assigned to ''Balizoma'', but were subsequently placed in other encrinurine genera.

References

External links

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''Balizoma'' in the

Paleobiology Database The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ...

*

Listing of ''Balizoma variolaris'' neotype in Online Collections at University of Birmingham registry. *

Listing in Official Lists and Indexes of Names and Works in Zoology, 1987 (page 307)] *

Listing in Official Lists and Indexes of Names and Works in Zoology, Supplement 1986-2000 (page 131) Encrinuridae Silurian trilobites of Europe Silurian animals of Europe Paleozoic life of the Northwest Territories Paleozoic life of Yukon Phacopida genera {{Phacopida-stub