''Illaenus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 At ...

s from

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

and

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

, from the middle

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...

. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profile and recurved genal spines. Eyes are distant from the axis of the head, situated nearer to the edge. Fossil Museum
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Selected species

This genus includes about 50 species: *''

Illaenus alveatus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Raymond 1925 *''

Illaenus auriculatus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Ross, Jr. & Barnes 1967 *''

Illaenus bayfieldi ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Billings 1859 *''

Illaenus bucculentus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Whittington 1963 *'' Illaenus consimilis'' Billings 1865 *'' Illaenus consobrinus'' Billings 1865 *'' Illaenus crassicauda'' Wahlenberg 1826 *'' Illaenus fraternus'' Billings 1865 *''

Illaenus gelasinus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end ...

'' Whittington 1965 *''

Illaenus lacertus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Whittington 1954 *'' Illaenus marginalis'' Raymond 1925 *''

Illaenus oscitatus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Fortey 1980 *''

Illaenus slancyensis ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Krylov 2016 *''

Illaenus spiculatus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Whittington 1963 *''

Illaenus tauricornis ''Illaenus tauricornis'' is a species of trilobites from Russia and Morocco, from the middle Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million year ...

'' Kutorga 1848 *''

Illaenus tumidifrons ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Billings 1865 *''

Illaenus utahensis ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Hintze 1952 *''

Illaenus welchi ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' Loch & Ethington 2017

References

*Yvonne Howells, "Ordovician Trilobites of St. Petersburg Region"

External links

Russian TrilobitesSaint Petesburg Paleontological Laboratory
Corynexochida genera Illaenina Ordovician trilobites Fossils of Morocco Fossils of Russia Bromide Formation Paleozoic life of Ontario Paleozoic life of Newfoundland and Labrador Paleozoic life of the Northwest Territories Paleozoic life of Nunavut Paleozoic life of Quebec Paleozoic life of Yukon {{Corynexochida-stub

Selected species

See also

References

External links