''Eubostrychoceras'' is a genus of helically wound, corkscrew form,

heteromorph The Ancyloceratina were a diverse suborder of ammonite most closely related to the ammonites of order Lytoceratina. They evolved during the Late Jurassic but were not very common until the Cretaceous period, when they rapidly diversified and bec ...

ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

which lived during the Upper

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

). The genus is included in the ancycleratid family

Nostoceratidae Nostoceratidae is a diverse Family (biology), family of heteromorph ammonites found throughout the oceans of the world during the Late Cretaceous. The nostoceratids are famous for the bizarre coiling of their shells. Many genera, such as ''Yezo ...

. The shell of ''Eubostrychoceras'' is a loosely to tightly wound spiral forming a corkscrew with an open, empty umbilicus in the middle. Coiling is commonly dextral (right hand). Coils are covered by moderately strong, straight transverse ribs. The aperture, or apertural end, reverses general direction and points upwards or back towards to apex. Sutures are moderately complex. The siphuncle is located mid flank. ''Eubostrychoceras'' has a widespread distribution in the Upper Createous and has been found in

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

, the far east of

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...

U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, and

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. In 2001 it was reported from Alaska's Matanuska Formation as well. ''E. japonicum'' is Turonian, and likely confined to the middle Turonian. Based on the similarity of textures and the curl of the shell as well as the stratigraphic relationships, ''E. valdelaxum'' from Japan is likely evolved from ''E. japonicum''. Related genera include '' Anaklinoceras'', '' Bostrychoceras'', '' Didymoceras'', and ''

Nostoceras ''Nostoceras'' is an extinct genus of ammonites. The etymology of the name ''Nostoceras'' comes from "nostos" meaning return and "ceros" meaning horn, named as such by Alpheus Hyatt because it bends back on itself. Taxonomy ''Nostoceras'' is the ...

''.

References

External links

* Ammonitida genera Fossil taxa described in 1967 Nostoceratidae Late Cretaceous ammonites of Europe Late Cretaceous ammonites of North America Ammonites of Asia Ammonites of Antarctica Fossils of Spain Fossils of the United States Fossils of Japan Fossils of France Fossils of Canada Fossils of Russia Fossils of Germany Fossils of Antarctica Fossils of Madagascar {{ammonitida-stub

References

Further reading

External links