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December 13th, 2011
| December 13th, 2011 | |
|---|---|
| 07:42 pm [industrialterro] [Link] |
Arcestes Arcestes is an extinct ammonite cephalopod genus belonging to the Ceratitida. Their shells were broad and rounded, giving them an almost spherical appearance. Unlike many other ammonites, the shells of Arcestes lack keels that would otherwise stabilize them while swimming. Because of this, some paleontologists have suggested that they were bottom-dwelling crawlers. The shell of Arcestes is globular or subglobular with periodic narrow transverse constrictions in internal molds due to periodic internal transverse ridges (variaces) in the shell. The suture is ammonitic with complexly subdivided elements. The ventral lobe is subdivided by a low median saddle. Lateral lobes and saddles have generally triangular outlines but are deeply embayed by strong projections forming tree-like patterns. They form a series diminishing in size and complexity in a rather straight line going from the venter to the umbilicus in the middle of the shell. Fossils of Arcestes are found in Mid to Upper Triassic marine strata throughout the world, including California (A. pacificus), Nevada (A (Anisarcestes) mrazici) and Austria (A. intuslabiatus and A. binacostomus).
Tags: Аммониты, Вымершие беспозвоночные, Триас |
| Time | Event |
| 07:55 pm [industrialterro] [Link] |
Balatonites Balatonites is an extinct cephalopod genus belonging to the ceratitid family Balatonitidae. There are at least four known species: B. balatonicus, B. oyama, B. shoshonensis, and B. zitteli. The shell of Balatonites is essentially evolute, coiled with earlier whorls showing, and is laterally compressed with flattish sides and a roof-like venter. The sides are covered with radial ribs that have tubercles generally arranged in umbilical, median and ventral rows. Balatonites has been found in the Alps, Balkans, Germany, Japan, and Nevada.
Tags: Аммониты, Вымершие беспозвоночные, Триас |
| Time | Event |
| 07:59 pm [industrialterro] [Link] |
Ceratites Ceratites ("Horn Stone") is an extinct genus of ammonite cephalopod that lived in marine habitats in what is now Europe, Asia, and North America during the Triassic. It has a ceratitic suture pattern on its shell.
Tags: Аммониты, Вымершие беспозвоночные, Триас |
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