''Calycoceras'' is an extinct genus of

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

s belonging to the subclass

Ammonoidea 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 ...

and

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Acanthoceratidae Acanthoceratidae is an extinct Family (biology), family of Acanthoceratoidea, acanthoceratoid cephalopods in the order Ammonitida, known from the Upper Cretaceous. The type genus is ''Acanthoceras (ammonite), Acanthoceras''. Diagnosis Acanthocer ...

that lived during the

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

stage of the Late

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 ...

, 100-94 Mya. Their shells had ornate ribs.

Species

*''C. algeriense'' Kennedy & Gale, 2017 *''C. annulatum'' Collignon, 1964 *''C. asiaticum'' (Jimbo, 1894)William James Kennedy, Herbert Christian Klinger (2010
Cretaceous faunas from Zululand and Natal, South Africa. The ammonite subfamily Acanthoceratinae de Grossouvre, 1894
/ref> **''C. a. asiaticum'' (Jimbo, 1894) **''C. a. spinosum'' (Kossmat, 1897) *''C. besairieri'' Collignon, 1937 *''C. boreale'' Kennedy, Cobban & Landman, 1996 *''C. dromense'' (Thomel, 1972) *''C. cenomanense'' (d’Archiac, 1846) *''C. navicularis'' (Mantell, 1822) *''C. orientale'' Matsumoto, Saito & Fukada *''C. paucinodatum'' (Crick) *''C. tarrantense''The Paleobiology Database
/ref>

Distribution

''Calycoceras'' species may be found in the Cretaceous of Angola, Antarctica, Canada (British Columbia), France, Germany, Japan, Nigeria, Oman, Russia, the United Kingdom, United States (Alaska, Arizona, Kansas, New Mexico, South Dakota, Utah) ''C. asiaticum'' may be found in the

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, Southern

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

, northern and southern

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

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 ...

Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...

Bulgaria Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...

Tunisia Tunisia, officially the Republic of Tunisia, is a country in the Maghreb region of North Africa. It is bordered by Algeria to the west and southwest, Libya to the southeast, and the Mediterranean Sea to the north and east. Tunisia also shares m ...

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 ...

, south

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

and

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 ...

.Paleobiology Database
/ref> ''C. cenomanense'' may be found in the Cenomanian of United Kingdom, France and Madagascar. Calycoceras orientale

Description

Shells of ''Calycoceras asiaticum'' may reach a diameter of about . The larger

phragmocone The phragmocone is the chambered portion of the shell of a cephalopod. It is divided by septa into camerae. In most nautiloids and ammonoids, the phragmocone is a long, straight, curved, or coiled structure, in which the camerae are linked by ...

s may reach in diameter. Coiling is moderately involute. All ribs show strong subspinose tubercles. ''C. asiaticum asiaticum'' and ''C. asiaticum spinosum'' are very similar, the latter has much more robust tuberculation.Ammonites
/ref>

References

{{Taxonbar, from=Q5024617 Acanthoceratidae Ammonitida genera Cretaceous ammonites Late Cretaceous ammonites of North America Late Cretaceous cephalopods of North America Late Cretaceous animals of Africa Cenomanian life