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 Devonian is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at 419.2 million years ago (Ma), to the beginning of the succeeding Carboniferous period at 358.9 Ma. It is named after Devon, South West England, where rocks from this period were first studied.
The Jurassic is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified.
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 Ma to the start of the Silurian Period 443.8 Ma.
Zooplankton are the animal component of the planktonic community, having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequently, they drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers.
The choreotrichs are a group of small marine ciliates. Their name reflects the impression that they appear to dance. The group includes the tintinnids, which produce species-specific loricae (shells), and are important because these may be preserved as microfossils. The cyst forms have been suggested to be affiliated to Chitinozoans, although other studies suggest Chitinozoans to have affinities to larger marine animals, and not tintinnids. Often they have been included among the oligotrichs. Tintinnids seem to be an excessively specious group as over 400 living species have been described, based on characteristics of the lorica or shell.
In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 149.2 ±0.7 Ma and 145.0 ± 4 Ma. It is preceded by the Kimmeridgian and followed by the Berriasian.
In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma. The Berriasian succeeds the Tithonian and precedes the Valanginian.
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.6 ± 2.0 Ma. The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceous and precedes the Hauterivian Stage of the Lower Cretaceous.
Tintinnids are ciliates of the choreotrich order Tintinnida, distinguished by vase-shaped shells, the name deriving from a Latin source meaning a small tinkling bell, that are called loricae, which are mostly protein but may incorporate minute pieces of minerals.
Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae, that lived during the Late Jurassic and the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea. No Geosaurus eggs or nests have been discovered, so little is known of the reptile's lifecycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to give birth to live young out at sea. Where Geosaurus mated, whether on land or at sea, is currently unknown. The name Geosaurus means "Mother of Giants lizard", and is derived from the Greek Ge- and σαῦρος -sauros ("lizard"). The name Geosaurus was established by the French naturalist Georges Cuvier in 1824.
Caypullisaurus is an extinct genus of platypterygiine ophthalmosaurid ichthyosaur from the Late Jurassic to the Early Cretaceous of Argentina. Its holotype was collected from the Vaca Muerta Formation of Cerro Lotena, Neuquen, dating to the early Tithonian stage of the Late Jurassic, about 150 million years ago. Caypullisaurus was first named by Marta Fernández in 1997 and the type species is Caypullisaurus bonapartei. It was a large ichthyosaur, measuring about 7 m (23 ft) long.
Protozoa are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically, protozoans were regarded as "one-celled animals".
Notoemys is an extinct genus of platychelyid turtle known from the Late Jurassic and Early Cretaceous of the Americas.
Neuquén Basin is a sedimentary basin covering most of Neuquén Province in Argentina. The basin originated in the Jurassic and developed through alternating continental and marine conditions well into the Tertiary. The basin bounds to the west with the Andean Volcanic Belt, to the southeast with the North Patagonian Massif and to the northeast with the San Rafael Block and to the east with the Sierra Pintada System. The basin covers an area of approximately 120,000 square kilometres (46,000 sq mi). One age of the SALMA classification, the Colloncuran, is defined in the basin, based on the Collón Curá Formation, named after the Collón Curá River, a tributary of the Limay River.
The Vaca Muerta Formation, commonly known as Vaca Muerta, is a geologic formation of Late Jurassic to Early Cretaceous age, located in the Neuquén Basin in northern Patagonia, Argentina. It is well known as the host rock for major deposits of shale oil and shale gas.
Wenupteryx is an extinct genus of pterodactyloid pterosaur known from the Late Jurassic Vaca Muerta of Neuquén Province, southern Argentina. It was first named by Laura Codorniú and Zulma Gasparini in 2013 and the type species is Wenupteryx uzi. It is a small-sized pterosaur related to the clade Euctenochasmatia or Archaeopterodactyloidea.
The Guasasa Formation is a geologic formation in Cuba. It is Tithonian to Early Valanginian in age and contains fossils of ammonites.
Platychelyidae is an extinct family of pan-pleurodiran turtles, known from the Late Jurassic and Early Cretaceous of Europe, South America, North America, and the Caribbean. It represents the oldest known clade of stem-pleurodires. All known members have been found in marine or coastal deposits. Despite this, their limb morphology suggests that they were not adapted for open marine conditions, but were likely inhabitants of shallow water environments, including brackish and saline waters, and they likely never inhabited environments more marine than lagoons. Their tolerance for saline environments likely aided their dispersal during the breakup of Pangea. Unlike modern pleurodires, which retract their necks to the sides, Platychelys retracted its neck inwards, similar to modern cryptodire turtles. Platychelys is strongly morphologically similar to mata mata and snapping turtles, suggesting that it had a similar ecology as a ram or suction feeder.
Foraminiferal tests are the tests of Foraminifera.
