''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 a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

which lived during the Upper Cretaceous (M

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...

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. Campanian s ...

). 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, Japan, Spain, the far east of Russia, Alaska, Vancouver Island, U.S. western interior, Germany, and Madagascar. In 2001 it was reported from Alaska's

Matanuska Formation The Matanuska Formation consists of more than of sedimentary strata exposed in the northern Chugach Mountains, Matanuska Valley, and southern Talkeetna Mountains of South-Central Alaska. The Matanuska Formation contains strata from Early Cretaceo ...

as well. ''E. japonicum'' is Turonian, and likely confined to the middle Turonian. Related genera include '' Anaklinoceras'', '' Bostychocdras'', ''

Didymoceras ''Didymoceras'' is an extinct genus of ammonite cephalopod from the Late Cretaceous epoch (approximately 76 Ma). It is one of the most bizarrely shaped genera, with a shell that spirals upwards into a loose, hooked tip. It is thought to have drif ...

'', 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 th ...

References

;Notes ;Bibliography * The upper Cretaceous ammonite ''Eubosrychoceras'' Matsumoto in the western interior of the United States by Willian A Cobban. U.S. Geological Survey bulletin—1690-A, Pub 1987. (Description and illustrations of an unusual ammonite from Wyoming, South Dakota, and New Mexico) * A New Species of the Heteromorph ammonite ''Eubostrychoceras'' from the Upper Cretaceous Frontier Formation, Natrona County, Wyoming

;We Links
Ammonites -Nostroceratidae
in French. Source of description.

External links

Ammonitida genera Nostoceratidae Late Cretaceous ammonites of Europe Late Cretaceous ammonites of North America Ammonites of Asia Ammonites of Antarctica Ammonites of Africa Fossils of Spain {{ammonitida-stub