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Ussuria
''Ussuria'' is a genus of Lower Triassic Ammonoidea, ammonites with a smooth, involute discoidal shell with submonophyllic sutures, belonging to the Ceratitida, ceratitid family Ussuriidae. ''Ussuria'' has been found in Russia in Siberia (original discovery), China, Oman, and Idaho in the United States. Description The shell of ''Ussuria'' is laterally compressed and involute. Whorls are deeply embracing, increasing rapidly in height. Umbilicus is narrow and deep with rounded shoulders. Sides gently convex, converging on a narrow-rounded venter. Sutures are ammonitic, with digitate lobes and submonophyllic saddles. The external, (or ventral), lobe is divided by a broad digitate siphonal saddle with each side of the lobe deeply trifid. The two or three principal lateral lobes on either side that are wide and deeply digitate, followed dorsally by another three or more smaller, also digitate, auxiliary lobes. The first lateral saddle is typically indented only on the ventral (rim) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ussuriidae
Ussuriidae is an extinct Family (biology), family of cephalopods belonging to the Ammonite order (biology), order Ceratitida and superfamily (taxonomy), superfamily Noritoidea. References The Paleobiology Database accessed 9/24/07 Noritoidea Ceratitida families {{Ceratitida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ; sometimes symbolized š) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is the first and shortest period of the Mesozoic Era and the seventh period of the Phanerozoic Eon. 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 PermianāTriassic 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
