Cheiruridae

Cheiruridae Temporal range: Furongian–Givetian PreЄ Є O S D C P T J K Pg N
Paraceraurus exsul, Middle Ordovician, St. Petersburg region, Russia
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Trilobita
Order:	Phacopida
Family:	Cheiruridae Hawle & Corda, 1847
subfamilies
Cheirurinae Hawle & Corda, 1847 Acantoparyphinae Wittington & Evitt, 1954 Cyrtometopinae Öpik, 1937 Deiphoniinae Raimond, 1913 Eccoptochilinae Lane, 1971 Heliomerinae Evitt, 1951 Pilekiinae Sdzuy, 1955 Sphaerexochinae Öpik, 1937

Cheiruridae is a family of phacopid trilobites of the suborder Cheirurina. Its members, as with other members of the suborder, had distinctive pygidia modified into finger-like spines. They first appeared near the very beginning of the Ordovician, and persisted until the Givetian (end of the Middle Devonian). Currently about 657 species assigned to 99 genera are included.^[1]

Distribution

The Cheirurinae with 269 species in 38 genera occur from the Floian to the Givetian and are probably monophyletic. The 109 species in 15 genera of the Acanthoparyphinae are also probably monophyletic, and are known from the Floian to the Ludfordian. The Cyrtometopinae were present between the Floian and the Upper Katian, envelloping 22 species in 5 genera, of which the monophyly is unclear. The Deiphoninae are probably monophyletic, occur from the Dapingian to the Gorstian, having 71 species assigned to 6 genera. The possibly paraphyletic Eccoptochilinae with 67 species in 13 genera are known between the Floian and upper Katian. The Heliomerinae are a small monophyletic group with 13 species in 2 genera. The Pilekiinae are the earliest subfamilily and therefore certainly paraphyletic, occurring in the upper Furongian and going extinct in the Darriwilian with 56 known species assigned to 19 genera. The monotypic Sphaerexochinae has about 50 species between the Floian and Přídolí.^[1]

Genera

References

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