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Eophyllites
''Eophyllites'' is a genus of ammonoid cephalopods from the Lower Triassic and a predecessor of genera like ''Monophyllites'' and ''Ussurites''. The shell of ''Eophyllites'' is evolute, discoidal; whorls compressed, deeply embracing; flanks gently convex, converging on a narrowly rounded venter. Sutures basically ceratitic; ventral lobe wide, divided by a high siphonal saddle; Lobesjagged, 1st lateral larger than the second; saddles monophyllic, smooth and rounded. Related ''Palaeophyllites ''Palaeophyllites'' is a genus of ammonoids from the Lower Triassic and a contemporary of the related ussuritid '' Eophyllites''. The shell of ''Palaeophyllites'' is evolute, inner whorls generally smooth, outer whorl with irregular ribs. Sutur ...'' from the same age is ribbed on the outer flanks and lobes in the suture are more terminally digitate. References * W.J. Arkell, et al., 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L. Geological Society of Ameri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeophyllites
''Palaeophyllites'' is a genus of ammonoids from the Lower Triassic and a contemporary of the related ussuritid '' Eophyllites''. The shell of ''Palaeophyllites'' is evolute, inner whorls generally smooth, outer whorl with irregular ribs. Sutures are basically ceratitic with digitate lobes and simple rounded monophyllic saddles. ''Paleophyllites'' differs from contemporary Eophyllites in having ribs on the outer part of the terminal whorl and lobes that are more quadrate in outline. Like ''Eophyllites'', ''Palaeophyllites'' is ancestral to genera like ''Ussurites'' and ''Monophyllites ''Monophyllites'' is an extinct cephalopod genus belonging to the family Ussuritidae that lived during the Triassic period, from Anisian to Ladinian age. Description "Form evolute laterally compressed. Whorl low and increasing slowly in height, ...''. References * W.J. Arkell ''et al.'', 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L. Geological Society of America ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of archo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonoidea
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 nea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyllites
''Monophyllites'' is an extinct cephalopod genus belonging to the family Ussuritidae that lived during the Triassic period, from Anisian to Ladinian age. Description "Form evolute laterally compressed. Whorl low and increasing slowly in height, little embracing and not deeply indented by the inner volution. Sides somewhat flattened, venter rounded with indistinct abdominal shoulders. Umbilicus wide and shallow exposing the greater part of the inner volutions. Umbilical shoulders abruptly rounded. The height of the whorl is more than one third of the total diameter of the shell and the breadth is about three fourths of the height of the whorl The width of the umbilicus is about one third of the total diameter of the shell. The surface is nearly smooth being ornamented only with the fiexuous striae of growth. The septa are monophyllic, the saddles rounded entire, contracted at the base and the lobes are digitate. The external lobe is divided by a narrow siphonal saddle into two bifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ussurites
''Ussurites'' is an extinct ammonoid cephalopod genus belonging to the suborder Phylloceratina and is included in the family Ussuritidae. Its range is restricted to the early Middle Triassic, (Anisian) As with the family, the shell of ''Ussurites'' is discoidal, evolute, and generally smooth. The suture is phylletic with divided lobes and simple, rounded, elongate saddles. The ventral lobe is bifurcated, the two branches sharply serrated. The two lateral lobes are asymmetrically trifurcated, sections sharply pointed. The first lateral saddle (closest to the venter) is fairly evenly rounded, the second and third are narrower and asymmetric, leaning away from the venter and toward the umbilicus. ''Monophyllites'', which extends through the Middle Triassic into the Carnian The Carnian (less commonly, Karnian) is the lowermost stage of the Upper Triassic Series (or earliest age of the Late Triassic Epoch). It lasted from 237 to 227 million years ago (Ma). The Carnian is precede ... [...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] |
Triassic Ammonites
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of archosaurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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