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Neocardioceras
''Neocardioceras'' is a genus of evolute acanthoceratid ammonites from the uppermost Cenomanian, Upper Cretaceous, of Europe, western U.S. and Brazil. As described in Cobban, Hook & Kenneday, 1989, ''Neocardioceras'' is a fairly small, moderately evolute, generally compressed ammonite that has prominent and very numerous rectoradiate to prorsiradate ribs and umbilical, inner and outer, and siphonal (mid ventral) tubercles. Primary ribs begin in the umbilicus or rise from umbilical tubercles and secondary ribs arise further out on the flank. The ribs bend forward at the position of the inner ventrolateral tubercles and cross the venter as chevrons, where they support the outer ventrolateral and siphonal tubercles. ''Neocardioceras'' was proposed by Spath, 1926, for ammonites "resembling '' Prionocyclus'' Meek, except for the ''Quenstedtoceras ''Quenstedtoceras'' is a genus of ammonoid cephalopods that lived during the latter part of the Jurassic period in what is now France, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenomanian
The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding age. Both age and stage bear the same name. As a unit of geologic time measure, the Cenomanian Age spans the time between 100.5 and 93.9 million years ago (Mya). In the geologic timescale, it is preceded by the Albian and is followed by the Turonian. The Upper Cenomanian starts around at 95 Mya. The Cenomanian is coeval with the Woodbinian of the regional timescale of the Gulf of Mexico and the early part of the Eaglefordian of the regional timescale of the East Coast of the United States. At the end of the Cenomanian, an anoxic event took place, called the Cenomanian-Turonian boundary event or the "Bonarelli event", that is associated with a minor extinction event for marine spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthoceratidae
Acanthoceratidae is an extinct family of acanthoceratoid cephalopods in the order Ammonitida, known from the Upper Cretaceous. The type genus is '' Acanthoceras''. Diagnosis Acanthoceratidae species are strongly tuberculate with at least umbilical and ventrolateral tubercles in most genera included. Ribs are dominant in some, in others weak or absent on the outer whorls. Most are evolute, compressed to very depressed in section. Sutures are ammonitic with little variation, but showing a tendency for simplication in later genera. Taxonomy Acanthoceratidae de Grossouvre, 1894 includes the following subfamilies. *Acanthoceratinae de Groussouvre, 1894 * Euomphaloceratinae Cooper, 1978 *Mammitinae Mammitinae comprises a subfamily within the Acanthoceratidae (Ammonoidea) characterized by moderately to very evolute shells with rectangular to squarish whorl sections along with blunt umbilical and prominent inner and outer ventrolateral tuberc ... (Hyatt, 1900) (= Fallotitinae Wie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quenstedtoceras
''Quenstedtoceras'' is a genus of ammonoid cephalopods that lived during the latter part of the Jurassic period in what is now France, Poland, Germany, and the United Kingdom. Morphologic description The shell of ''Quenstedtoceras'' is typically evolute and strongly ribbed, with all whorls visible. Widths vary according to the species from rather narrow to somewhat broad, as does ribbing. Ribs commonly start at the umbilical shoulder and extend laterally to about mid flank where they divide and curve forward toward the outer rim, or venter, and meet at a keel. Shells are of moderate size, commonly reaching diameters of about 6 cm (2.4 in). Taxonomy and phylogeny ''Quenstedtoceras'', included in the superfamily Stephanocerataceae, now revised to Stephanoceratoidea, is first of the subfamily Cardioceratinae, derived from '' Cadoceras'' or related genus is the mid or late Callovian and gave rise at the end of its range in the early Oxfordian to ''Cardioceras ''Cardio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonitida Genera
Ammonitida is an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures. Ammonitida is divided into four suborders, the Phylloceratina, Lytoceratina, Ancyloceratina, and Ammonitina. The Phylloceratina is the ancestral stock, derived from the Ceratitida near the end of the Triassic. The Phylloceratina gave rise to the Lytoceratina near the beginning of the Jurassic which in turn gave rise to the highly specialized Ancyloceratina near the end of the Jurassic. Both the Phylloceratina and Lytoceratina gave rise to various stocks combined in the Ammonitina. These four suborders are further divided into different stocks, comprising various families combined into superfamilies. Some like the Hildoceratoidea and Stephanoceratoidea are restricted to the Jurassic. Others like the Hoplitoidea and Acanthoceratoidea are known only from the Cretaceous. Still others like the Perisphinctoidea are found in both. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous Ammonites
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonites Of North America
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) than they are to shelled nautiloids such as the living ''Nautilus'' species. The earliest ammonites appeared during the Devonian, with the last species vanishing during the Cretaceous–Paleogene extinction event. Ammonites are excellent index fossils, and linking the rock layer in which a particular species or genus is found to specific geologic time periods is often possible. Their fossil shells usually take the form of planispirals, although some helically spiraled and nonspiraled forms (known as heteromorphs) have been found. The name "ammonite", from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams' horns. Pliny the Elder ( 79 AD near Pompe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
