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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 ''Yezoceras'', ''Ainoceras'', ''Anaklinoceras'', and some species of ''Bostrychoceras'' and ''Eubostrychoceras'', display, as young shells at least, a helical coiling very similar to the shells of the related family, Turrilitidae. As adults, though, the coils then curve away from the axis of coiling, either as an oxbow-like curve around the juvenile coils as in ''Ainoceras'' and ''Anaklinoceras'', or in a simple curved loop beneath the juvenile coils, as in ''Yezoceras''. Other genera form loose coils, sometimes in a spiral, such as those of ''Madagascarites'', ''Muramotoceras'', ''Hyphantoceras'', and the infamously convolute ''Nipponites''. The ecology of nostoceratids is the subject of continued speculation, as the bizarrely coiled shells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 type genus for the ammonite family Nostoceratidae which is included in the Turrilitoidea. The Turrilitoidea, with ''Nostoceras'' and the Nostoceratidae, are commonly included in the suborder Ancyloceratina but may instead belong in the Turrilitina, a proposed order of heteromorphs thought to have a separate derivation, though this separation does not have wide support. Fossil record Fossils of ''Nostoceras'' are found in marine strata from the Campanian stage of the Upper Cretaceous, in the USA, England, central Europe, west Africa, Australia and Madagascar (Angola, Australia, Austria, Belgium, Denmark, England, France, Germany, Iraq, Italy, Madagascar, the Netherlands, Nigeria, Oman, Spain, United States). Description Nostoceras is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ''Yezoceras'', ''Ainoceras'', ''Anaklinoceras'', and some species of ''Bostrychoceras'' and ''Eubostrychoceras'', display, as young shells at least, a helical coiling very similar to the shells of the related family, Turrilitidae. As adults, though, the coils then curve away from the axis of coiling, either as an oxbow-like curve around the juvenile coils as in ''Ainoceras'' and ''Anaklinoceras'', or in a simple curved loop beneath the juvenile coils, as in ''Yezoceras''. Other genera form loose coils, sometimes in a spiral, such as those of ''Madagascarites'', ''Muramotoceras'', ''Hyphantoceras'', and the infamously convolute ''Nipponites''. The ecology of nostoceratids is the subject of continued speculation, as the bizarrely coiled shells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muramotoceras
''Muramotoceras'' was an unusual genus of heteromorphic ammonite. It was known only from Japan until researchers reported in 2001 that the genus was present in Alaska's Matanuska Formation as well. Its remains likely date to the middle Turonian (from 89.8 to 93.9 million years ago) in both areas. Subsequently it was also described from the Santonian Gosau Group (Austria). See also * List of ammonites This list of ammonites is a comprehensive listing of Genus, genera that are included in the subclass †Ammonoidea, excluding purely vernacular terms. The list includes genera that are commonly accepted as valid, as well those that may be invalid ... Footnotes References * External links Paleotheque Ammonitida genera Nostoceratidae Late Cretaceous ammonites of North America Ammonites of Asia {{ammonitida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eubostrychoceras
''Eubostrychoceras'' is a genus of helically wound, corkscrew form, heteromorph ammonite which lived during the Upper Cretaceous (M Turonian - Campanian). The genus is included in the ancycleratid family Nostoceratidae. 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 as well. ''E. japonicum'' is Turonian, and likely confined to the middle Turon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exiteloceras
''Exiteloceras'' is an ammonite genus from the Late Cretaceous. ''Exiteloceras'' was proposed by Alpheus Hyatt in 1894 for heteromorph ammonites with shells that are loosely coiled in a plane, early whorls varying from straight limbs connected by semicircular elbows to elliptical or nearly circular loops, later whorls being elliptical to circular. The whorl section is ovate with the dorsum on the inside curve broader than the venter on the outside. The ribs may be straight or flexuous {{Short pages monitor [Baidu] |
Axonoceras
''Axonoceras'' is a genus in the ammonitid family Nostoceratidae proposed by Stephenson in 1941, for "slender shells coiled in a plane with numerous closely spaced ribs and two rows of ventral nodes'...The shells may be closely coiled, though not involute, but most... are more or less loosely and irregularly coiled". Shells may be coplanar or coiled in a low flat spiral with the early whorls in contact, later whorls free. ''Axonoceras'' comes from the Campanian of Texas and New Jersey in the United States and Angola , national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordina ... in west Aftrica. The type species is ''Axonoceras compressum'' Stephenson 1941. ''Axonoceras'' and '' Exiteloceras'' are similar with ''Axonoceras'' sometimes considered a subjective synonym of ''Exiteloceras''. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bostrychoceras
''Bostrychoceras'' is a genus of heteromorph ammonite from the family Nostoceratidae. Fossils have been found in Late Cretaceous sediments in Europe and North America. The shell of ''Bostrychoceras'' begins as a tightly wound helical spire, like that of ''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 ...'', from which hangs a U or J shaped body chamber, at least in the adult. The shell is covered with dense, strong, but un-flaired, ribs that are commonly sinuous and oblique. May nor may not have strong constrictions. Distribution Cretaceous of Nigeria, Peru, South Africa, Spain and the United States References ;Notes ;Bibliography * * ''Ammonoid Paleobiology'' (Topics in Geobiology) by Neil H. Landman, Kazushige Tanabe, and Richard Arnold Davis Ammonitida gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 drifted in the water vertically, moving up and down. The generic name is Greek for "paired horns". Its taxonomic place is often in flux, being placed in either Turrilitidae, 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 ..., or its own family, Didymoceratidae. Species included in the genus are the following: *''Didymoceras angulatum'' (Meek and Hayden, 1860) *''Didymoceras binodosum'' Kennedy and Cobban, 1993 *''Didymoceras californicum'' Anderson, 1958 *''Didymoceras cheyenense'' (Meek and Hayden, 1856) *''Didymoceras chey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nipponites
''Nipponites'' is an extinct genus of heteromorph ammonites. The shells of ''Nipponites'' (primarily ''N. mirabilis'') form "ox-bow" bends, resulting in some of the most bizarre shapes seen among ammonites. The ecology of ''Nipponites'', as with many other nostoceratids, is subject to much speculation. Distribution Fossils of most species are found primarily in Upper Cretaceous strata of Japan. ''N. mirabilis'' is found in Coniacian-aged strata of Japan and possibly Turonian-aged strata in Madagascar. ''N. bacchus'' is found in Upper Cretaceous Hokkaido. Two species are found exclusively outside Japan, ''N. sachalinensis'', which is found in Upper Cretaceous strata of Sakhalin island, and Kamchatka peninsula,Shigeta, Yasunari, and Haruyoshi Maeda. "Yezo Group research in Sakhalin—a historical review." National Science Museum Monographs 31 (2005): 1-24. and ''N. occidentalis'', which is known from two shells found in the Turonian The Turonian is, in the ICS' geologic tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turrilitoidea
Turrilitoidea is a diverse superfamily of Cretaceous ammonites generally considered as heteromorphic and commonly included in the suborder Ancyloceratina. Shells of this diverse group do not coil planospirally, as typical for most ammonitida, ammonites, but rather take on a variety of unique forms. Separation of Turrilitoidea along with Ptychoceratoidea and Scaphatoidea into a different suborder, Turrilitina, was proposed by Beznosov and Mikhailova in 1983 however this view is not accepted by most authors. Some, such as the eponymous ''Turrilites'', coiled helically, like an auger shell, while others, such as ''Hamites (genus), Hamites'', had shells with long straight sections, while the one-of-a-kind ''Nipponites'' coiled in a way so as to appear as a ball of knots. As with other ammonites, the last of the Turrilitoidea had perished by the end of the Cretaceous during the Cretaceous–Paleogene extinction event. References * Arkell ''et al.'', 1957. Mesozoic Ammonoidea,' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 became one of the most distinctive components of Cretaceous marine faunas. They have been recorded from every continent and many are used as zonal or index fossils. The most distinctive feature of the majority of the Ancyloceratina is the tendency for most of them to have shells that are not regular spirals like most other ammonites. These irregularly-coiled ammonites are called heteromorph ammonites, in contrast to regularly coiled ammonites, which are called homomorph ammonites. Biology The biology of the heteromorph ammonites is not clear, but one certainty is that their uncoiled shells would have made these forms very poor swimmers. Open shells, particularly ones with spines and ribs, create a lot of drag; but more importantly, the orien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ainoceras
''Ainoceras'' ("Ainu's Horn") is a genus of extinct, aberrantly coiled ammonite cephalopod that live in the Pacific Ocean during the Campanian division of the Cretaceous, where Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ... is today. Their shells were coiled very similarly to the related '' Anaklinoceras'', in that, when young, the shell coiled helically, and then upon reaching adulthood, the shell then bent over the older coils. However, ''Ainoceras'' differed in this respect in that, whereas in ''Anaklinoceras'', the youngest coil wrapped very closely around the older coils, while in ''Ainoceras'', the youngest coil bent over the older coils in a wide loop or oxbow. References Ammonitida genera Nostoceratidae Ammonites of Asia Late Cretaceous ammonites L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
