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Calpionellites Darderi
''Calpionellites darderi'' is an extinct planktonic eukaryote and an important index fossil for the Lower Cretaceous stratigraphy. The first appearance of ''C. darderi'' marks the beginning of the Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 137.05 ± 0.2 Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretac .... It also defines the base of the "Calpionellid Zone E". The species was first described by Colom in 1934 and is part of the Calpionellites genus. References Index fossils Spirotrichea Ciliate species Fossil taxa described in 1934 {{Paleo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valanginian
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 137.05 ± 0.2 Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceous and precedes the Hauterivian Stage of the Lower Cretaceous. Stratigraphic definitions The Valanginian was first described and named by Édouard Desor in 1853. It is named after Valangin, a small town north of Neuchâtel in the Jura Mountains of Switzerland. The base of the Valanginian is at the first appearance of calpionellid species '' Calpionellites darderi'' in the stratigraphic column. A global reference section (a GSSP) had in 2009 not yet been appointed. The top of the Valanginian (the base of the Hauterivian) is at the first appearance of the ammonite genus '' Acanthodiscus''. Subdivision The Valanginian is often subdivided in Lower and Upper substages. The Upper substage begins at the first appearance of ammonite speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planktonic
Plankton are the diverse collection of organisms that drift in water (or air) but are unable to actively propel themselves against currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales. Marine plankton include bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in lakes and rivers. Mostly, plankton just drift where currents take them, though some, like jellyfish, swim slowly but not fast enough to generally overcome the influence of currents. Although plankton are usually thought of as inhabiting water, there are also airborne versions that live part of their lives drifting in the atmosphere. These '' aeroplankton'' include plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Cretaceous
Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker * Lower (surname) * Lower Township, New Jersey *Lower Receiver (firearms) * Lower Wick Gloucestershire, England See also * Nizhny {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calpionellites
''Calpionellites'' is an extinct genus of single celled eukaryotes.''Calpionellites'' at .org Their fossils are found in rocks dating to the stage of the . Biostratigraphic significance The first occurrence of the species ''Calpionellites darderi'' marks the beginning of the |
Index Fossils
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. "Biostratigraphy." ''Oxford Reference: Dictionary of Biology'', 8th ed., Oxford University Press, 2019. The primary objective of biostratigraphy is ''correlation'', demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to help identify biozones, as they make up the basic biostratigraphy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliate Species
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar Suctoria only have them for part of their life cycle) and are variously used in swimming, crawling, attachment, feeding, and sensation. Ciliates are an important group of protists, common almost anywhere there is water—in lakes, ponds, oceans, rivers, and soils, including anoxic and oxygen-depleted habitats. About 4,500 unique free-living species have been described, and the potential number of extant species is estimated at 27,000–40,000. Included in this number are many ectosymbiotic and endosymbiotic species, as well as some obligate and opportunistic parasites. Ciliate species range in size from as little as 10 μm in some colpodeans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
