| Taraises Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Formation |
| Underlies | Cupido Formation |
| Overlies | La Caja Formation, La Casita Formation |
| Lithology | |
| Primary | Marl |
| Other | Limestone |
| Location | |
| Country | Mexico |
The Taraises Formation is a geologic formation in northern Mexico. It preserves fossils dating back to the Early Cretaceous, including ammonites. [1]
Baculites is an extinct genus of cephalopods with a nearly straight shell, included in the heteromorph ammonites. The genus, which lived worldwide throughout most of the Late Cretaceous, and which briefly survived the K-Pg mass extinction event, was named by Lamarck in 1799.
Berriasella is a discoidal evolute perisphinctacean ammonite, and type genus for the neocomitid subfamily Berriasellinae. Its ribbing is distinct, consisting of both simple and bifurcated ribs that extend from the umbilical seam across the venter; its whorl section generally compressed, the venter more or less narrowly rounded. The species Berriasella jacobi traditionally has been regarded an index fossil defining the base of the Cretaceous, however since 2016 this had been replaced by the first occurrence of Calpionella alpina. Some authors regard B. jacobi as instead belonging to the genus Strambergella.
Exiteloceras is an ammonite genus from the Late Cretaceous.
Douvilleiceras is a genus of ammonites from the Middle to Late Cretaceous. Its fossils have been found worldwide, in Africa, Asia, Europe, and North and South America.
Discoscaphites is an extinct genus of ammonite. This genus may have been one of the few to have briefly survived the K-Pg mass extinction.
Wrightoceras is an extinct genus of cephalopod, belonging to the Ammonite subclass, that lived during the Turonian epoch of the Late Cretaceous.
Sphenodiscus is an extinct genus of acanthoceratacean ammonite. The genus has been found from many continents and is thought to have had a large global distribution during the Maastrichtian stage of the Late Cretaceous. It was one of the last ammonoids to have evolved before the entire subclass became extinct at the end of the period during the Cretaceous–Paleogene extinction event.
Neoptychites is an extinct ammonoid cephalopod genus from the Turonian stage of the Upper Cretaceous, with a worldwide distribution.
Coilopoceras is a compressed, involute, lenticular ammonitid from the Cretaceous, with a narrow venter and raggedy ammonitic suture; type of the Coilopoceratidae, a family in the Acanthoceratoidea of the suborder Ammonitina.
Eubostrychoceras is a genus of helically wound, corkscrew form, heteromorph ammonite which lived during the Upper Cretaceous. The genus is included in the ancycleratid family Nostoceratidae.
Hoplitoides is an ammonite from the Upper Cretaceous, Turonian belonging to the Coilopoceratidae, a family in the Acanthoceratoidea. Hoplitoides have early whorls which are grooved, then flat, and finally narrowly rounded venters; early stages with umbilical tubercles and space ribs, later stages becoming smooth. The suture is similar to that of Coilopoceras but less extreme. Hoplitoides has an established distribution which is widespread, from western North America, northwestern Africa and northern South America.
Macroscaphites is an extinct cephalopod genus included in the Ammonoidea that lived during the Barremian and Aptian stages of the Early Cretaceous. Its fossils have been found throughout most of Europe and North Africa.
Calycoceras is an extinct genus of cephalopods belonging to the subclass Ammonoidea and family Acanthoceratidae that lived during the Cenomanian stage of the Late Cretaceous, 100-94 Mya. Their shells had ornate ribs.
The Tinton Formation is a geologic formation in New Jersey. It preserves fossils dating back to the Cretaceous-Paleocene periods, such as ammonites.
The Saratoga Chalk is a geologic formation in Arkansas. It preserves fossils dating back to the Cretaceous period, specifically ammonites.
The La Caja Formation is a geologic formation in Mexico. It preserves fossils datiting from the Kimmeridgian to the lower Berriasian. La Caja Formation is widespread in northeastern and central Mexico and known for their abundant and diverse well-preserved ammonites. It was deposited in hemipelagic conditions, and predominantly consists of siliclastic sediments, including marl, with limestone. It is laterally equivalent to the La Casita Formation, which represent more proximal facies. The ichthyosaurs Ophthalmosaurus icenicus and Parrassaurus yacahuitztli, metriorhynchid Cricosaurus saltillensis and the giant pliosaur "Monster of Aramberri" are known from the formation.
The Carbonera Formation is a geologic formation in Mexico. It preserves fossils dating back to the Berriasian to Hauterivian stages of the Early Cretaceous period.
Quitmaniceras is a genus of small, compressed, fairly evolute ammonites from the lower Turonian of Grant County, New Mexico and Trans-Pecos Texas, included in the subfamily Acanthoceratinae. The shell has a carinate venter in juveniles and one that is arched in adults, usually with a raised siphonal line,(siphonal referring to the marginal siphuncle). Ribs are very weak to moderately strong, flexious, typically sloping forward toward the rim, bending further forward at the outer shoulder.
This list, 2017 in paleomalacology, is a list of new taxa of ammonites and other fossil cephalopods, as well as fossil gastropods, bivalves and other molluscs that are scheduled to be described during the year 2017, as well as other significant discoveries and events related to molluscan paleontology that are scheduled to occur in the year 2017.
Macroscaphitidae is an extinct family of ptychoceratoid cephalopods from the subclass Ammonoidea that lived from the Lower Barremian to the Lower Cenomanian stages of the Cretaceous. Fossils of Macroscaphitidae were found all around the world although the abundance of found fossils is rather limited. Known fossils from collections were found largely in Europe, South America and Africa. It is known for some species of which complete specimens were found that these animals developed a hetermorphic shell, i.e. the coiling of the shell was not regular, such that the first whirls formed a planispirally coiled evolute section as seen in homomorphic ammonites, but had an additional straight middle part and a presumably upwards facing aperture. Due to their odd morphology the taxonomic classification of Macroscaphitidae changed often over time since their discovery and may not be finally settled even now.
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