''Cyclopyge'' is a genus of small to average size

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 that lived during the

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 of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

. Like all members of the family Cyclopigidae, it has very large convex eyes, that cover most of the free cheeks, and in some species touch each other. The eyes almost touch the large glabella. The occipital ring has merged with the rest of the glabella. The glabella does not extend into a frontal thorn. The cephalon lacks genal spines. The 6 thorax segments have short pleurae. The pygidium is rather large, and often rather effaced. These are features that also occur in other Cyclopygidae, and are indications of a

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

lifestyle.Whittington, H. B. et al. Part O, Treatise on Invertebrate Paleontology. Revised, Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida. 1997

Taxonomy

The genus was first named ''Egle'' by Barrande, but that name was not available, since it was used by Robineau-Desvoidy before for
willow catkin fly
of the

Anthomyiidae The Anthomyiidae are a large and diverse family of Muscoidea flies. Most look rather like small houseflies, but are commonly drab grey. The genus ''Anthomyia'', in contrast, is generally conspicuously patterned in black-and-white or black-and- ...

family.

Species previously assigned to ''Cyclopyge''

* ''C. binodosa'' = '' Pricyclopyge binodosa'' * ''C. genatenta'' = '' Prospectatrix genatenta''

Species that may be confused with ''Cyclopyge''

* The agnostid trilobite '' Pseudagnostus cyclopyge'', or previously known as ''Agnostus cyclopyge''. * The agnostid trilobite '' Rhaptagnostus cyclopygeformis'', or previously known as ''Agnostus cyclopygeformis''. * The butterfly previously known as '' Cyclopyge'' Mielke, 2002. * The millipede '' Rhamphidarpoides cyclopyge'', belonging to the Spirostreptida order.

Distribution

As pelagic creatures, cyclogygids were not bound to shallow waters surrounding continents and islands. At the time they lived, continents weren't blocking the exchange between different parts of the ocean, and this means they probably had large distributions, comprising one or more climate zones worldwide. ''Cyclopyge'' is well known from the Czech Republic, Morocco, England, Sweden, Canada (Newfoundland) and the United States. * ''Cyclopyge recurva'' occurs in the Ordovician of China (Pagoda Formation of southwestern Shaanxi).

References

Cyclopygidae Asaphida genera Ordovician trilobites of Europe Ordovician trilobites of Africa Ordovician trilobites of North America Ordovician trilobites of Asia Paleozoic life of Quebec {{Asaphida-stub