''Eldredgeia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...

s in the order

Phacopida Phacopida ("lens-face") is an order of trilobites that lived from the Late Cambrian to the Late Devonian. It is made up of a morphologically diverse assemblage of taxa in three related suborders. Characteristics Phacopida had 8 to 19 thorac ...

, suborder

Phacopina The Phacopina comprise a suborder of the trilobite order Phacopida. Species belonging to the Phacopina lived from the Lower Ordovician (Tremadocian) through the end of the Upper Devonian (Famennian).Moore, R.C. (ed.). Treatise on Invertebrate Pale ...

, family

Calmoniidae Calmoniidae is a family of trilobites from the order Phacopida, suborder Phacopina, superfamily Acastoidea. It contains the following genera: *''Anchiopella'' *''Andinacaste'' *''Australocaste'' *''Australops'' *''Awaria'' *''Bainella'' *''Belen ...

. This genus comes from the

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

and

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

, usually found in nodules. The trilobite ''Eldredgeia venusta'', from

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

, is the most common South American trilobite on today's fossil market, and even then it is not all that common. This genus has a spiny

pygidium The pygidium (plural pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is com ...

and usually the eye facets are well preserved.

Species

*''Eldredgeia venustus'' from the Sicasica Formation, La Paz Department, Bolivia (holotype). Also known from the Upper Member of the Belén Formation, La Paz Department,Gloria Pirés de Carvalho, M. da, G.D. Edgecombe, and L. Smith. New Calmoniid Trilobites (Phacopina: Acastoidea) from the Devonian of Bolivia. ''American Museum Novitates'', nr. 3407. 200

/ref> and the Pimenteira Formation

Givetian The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian Stage. It is named after the town of Givet in ...

*''Eldredgeia cf. E. venustus'' from South Africa.

Eifelian The Eifelian is the first of two faunal stages in the Middle Devonian Epoch. It lasted from 393.3 ± 1.2 million years ago to 387.7 ± 0.8 million years ago. It was preceded by the Emsian Stage and followed by the Givetian Stage. North American ...

. *''Eldredgeia paituna'' (Hartt and Rathbun 1875) from the Erere Sandstone, Para, Brazil. Eifelian. *''Eldredgeia eocryphaeus'', from the Lower Member of the Belén Formation, Scaphiocoelia Assemblage Zone, Tikani, Estacion de Bombeo, Sicasica, La Paz Department (holotype). Also collected from the Gamoneda Formation, Cerro Picacho, 17 km S of Tarija, Tarija Department. Late

Lochkovian The Lochkovian is one of three faunal stages in the Early Devonian Epoch. It lasted from 419.2 ± 3.2 million years ago to 410.8 ± 2.8 million years ago. It marked the beginning of the Devonian Period, and was followed by the Pragian Stage. It ...

to early

Pragian The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 410.8 ± 2.8 million years ago to 407.6 ± 2.8 million years ago. It was preceded by the Lochkovian Stage and followed by the Emsian Stage. The most important ...

. File:Eldredgeia venusta thorax.jpg, ''Eldredgeia venustus'' File:Eldredgeia venusta cephalon.jpg, ''Eldredgeia venustus'', dorsal view of the head File:Eldredgeia eocryphaea obliquefrontal 2.jpg, ''Eldredgeia eocryphaea'' File:Eldredgeia eocryphaea negative.jpg, ''Eldredgeia eocryphaea'', negative imprint

References

Calmoniidae Phacopida genera Devonian trilobites of South America {{phacopida-stub