''Rafinesquina'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 ...

of large

brachiopod Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, w ...

that existed from the

Darriwilian The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species '' ...

to the

Ludlow epoch In the geological timescale, the Ludlow Epoch (from 427.4 ± 0.5 million years ago to 423.0 ± 2.3 million years ago) occurred during the Silurian Period, after the end of the Homerian Age. It is named for the town of Ludlow in Shropshire, England ...

. The genus was named in honor of

polymath A polymath ( el, πολυμαθής, , "having learned much"; la, homo universalis, "universal human") is an individual whose knowledge spans a substantial number of subjects, known to draw on complex bodies of knowledge to solve specific pro ...

Constantine Samuel Rafinesque Constantine Samuel Rafinesque-Schmaltz (; October 22, 1783September 18, 1840) was a French 19th-century polymath born near Constantinople in the Ottoman Empire and self-educated in France. He traveled as a young man in the United States, ultimat ...

Description

''Rafinesquina's'' members were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders. ''Rafinesquina'' normally have a concavo-convex profile, with radiating striae of alternating size which are crossed with finer concentric striae. Their width is usually greater than their length, like most Strophomenids. Members of this genus had shells that grew in increments, with each increment forming a layer of the shell (much like

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s do with their

rings Ring may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell :(hence) to initiate a telephone connection Arts, entertainment and media Film and ...

). In 1982, Gary D. Rosenberg analyzed specimens of '' Rafinesquina alternata'' previously inferred to have lived in a shallow

subtidal The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated ...

environment and proposed it could be possible to estimate the total number of days in a

lunar month In lunar calendars, a lunar month is the time between two successive syzygies of the same type: new moons or full moons. The precise definition varies, especially for the beginning of the month. Variations In Shona, Middle Eastern, and Europ ...

(the period between

full moon The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (when the ecliptic coordinate system, ecliptic longitudes of the Sun and Moon opp ...

s) during the

Late 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. The ...

using layer counting.

Distribution

''Rafinesquina'' specimens had a cosmopolitan distribution, and their fossils can be found in

the Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North America, North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

, and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

.Fossilworks
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Species

Species in the genus ''Rafinesquina'' include:Catalog of Life
/ref> *'' R. alternata'' (Conrad, 1838) *'' R. declivis'' (James, 1874) *'' R. delicata'' Williams, 1974 *'' R. deltoidea'' (Conrad, 1838) *'' R. insidiosa'' Williams, 1962 *'' R. jeffersonensis'' Bradley, 1930 *'' R. latisculptilus'' (Savage, 1913) *'' R. lignani'' Vilas, 1985 *'' R. mesicosta'' Shumard, 1860 *'' R. mucronata'' Foerste, 1914 *'' R. nasuta'' (Emmons, 1842) *'' R. oanduensis'' Oraspold, 1956 *'' R. orvikui'' Oraspold, 1956 *'' R. percensis'' Cooper and Kindle, 1936 *'' R. planulata'' Cooper, 1956 *'' R. ponderosa'' Hayes and Ulrich, 1903 *'' R. pseudoloricata'' (Barrande, 1848) *'' R. relicula'' Benedetto, 1995 *'' R. stropheodontoides'' (Savage, 1913) *'' R. trentonensis'' (Hall, 1847) *'' R. ultrix'' Marek and Havlíček, 1967 *'' R. urbicola'' Marek and Havlíček, 1967

References

Prehistoric brachiopod genera Ordovician brachiopods Silurian brachiopods Paleozoic animals of Asia Paleozoic animals of Europe Paleozoic animals of North America Paleozoic animals of South America Paleozoic brachiopods of Asia Paleozoic brachiopods of Europe Paleozoic brachiopods of North America Paleozoic brachiopods of South America Fossils of Argentina Fossils of Belarus Fossils of Bolivia Fossils of Canada Paleozoic life of British Columbia Paleozoic life of Manitoba Paleozoic life of Newfoundland and Labrador Paleozoic life of the Northwest Territories Paleozoic life of Nunavut Paleozoic life of Ontario Verulam Formation Paleozoic life of Quebec Fossils of China Fossils of the Czech Republic Letná Formation Fossils of Estonia Fossils of France Fossils of Latvia Fossils of Lithuania Fossils of North Korea Fossils of Norway Fossils of Portugal Fossils of Russia Fossils of South Korea Fossils of Spain Fossils of Great Britain Fossils of the United States Fossils of Georgia (U.S. state) Fossils of Venezuela Fossil taxa described in 1892 {{brachiopod-stub