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Living Fossils
A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are of species-poor lineages, but they need not be. While the body plan of a living fossil remains superficially similar, it is never the same species as the remote relatives it resembles, because genetic drift would inevitably change its chromosomal structure. Living fossils exhibit stasis (also called "bradytely") over geologically long time scales. Popular literature may wrongly claim that a "living fossil" has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological changes. Scientific investigations have repeatedly discredited such claims. The minimal superficial changes to living fossils are mistakenly declared as an absence of evolution, but they are examples of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelacanth CAS 1
The coelacanths ( ) are fish belonging to the order Actinistia that includes two extant species in the genus ''Latimeria'': the West Indian Ocean coelacanth (''Latimeria chalumnae''), primarily found near the Comoro Islands off the east coast of Africa, and the Indonesian coelacanth (''Latimeria menadoensis''). The name "coelacanth" originates from the Permian genus ''Coelacanthus'', which was the first scientifically named coelacanth. Coelacanths follow the oldest-known living lineage of Sarcopterygii (lobe-finned fish and tetrapods), which means they are more closely related to lungfish and tetrapods (which includes amphibians, reptiles, birds and mammals) than to ray-finned fish. They are found along the coastline of Indonesia and in the Indian Ocean. The West Indian Ocean coelacanth is a critically endangered species. The oldest known coelacanth fossils are over 410 million years old. Coelacanths were thought to have become extinct in the Late Cretaceous, around 66 milli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latimeria
''Latimeria'' is a rare genus of fish which contains the only living species of coelacanth. It includes two Extant taxon, extant species: the West Indian Ocean coelacanth (''Latimeria chalumnae'') and the Indonesian coelacanth (''Latimeria menadoensis''). They follow the oldest known living Lineage (evolution), lineage of Sarcopterygii (lobe-finned fish and tetrapods), which means they are more closely related to lungfish and Tetrapod, tetrapods (Amphibian, amphibians, reptiles and mammals) than to the common ray-finned fishes and Chondrichthyes, cartilaginous fishes. They are found along the coastlines of the Indian Ocean and Indonesia. Since there are only two species of coelacanth and both are threatened, it is one of the most endangered genera of animals in the world. The West Indian Ocean coelacanth is a critically endangered species. Biological characteristics Based on growth rings in the creatures' ear bones (otoliths), scientists infer that individual coelacanths may l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinocysts
Dinocysts or dinoflagellate cysts are typically 15 to 100 µm in diameter and produced by around 15–20% of living dinoflagellates as a dormant, zygotic stage of their lifecycle, which can accumulate in the sediments as microfossils. Organic-walled dinocysts are often resistant and made out of dinosporin. There are also calcareous dinoflagellate cysts and siliceous dinoflagellate cysts. History The first person to recognize fossil dinoflagellates was Christian Gottfried Ehrenberg, who reported his discovery in a paper presented to the Berlin Academy of Sciences in July 1836. He had observed clearly tabulate dinoflagellates in thin flakes of Cretaceous flint and considered those dinoflagellates to have been silicified. Along with them, and of comparable size, were spheroidal to ovoidal bodies bearing an array of spines or tubes of variable character. Ehrenberg interpreted these as being originally siliceous and thought them to be desmids (freshwater conjugating algae), pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinoflagellates
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are mostly marine plankton, but they also are common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy and myzocytosis). In terms of number of species, dinoflagellates are one of the largest groups of marine eukaryotes, although substantially smaller than diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, ''Oodinium'' and ''Pfiesteria''). Some dinoflagellates prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syntexis Libocedrii
''Syntexis libocedrii'', (also called the cedar wood wasp or incense-cedar wood wasp) is the only living species in the wood wasp family Anaxyelidae, within the Symphyta, though the family has an extensive Mesozoic fossil record. This species is thus a "living fossil". It has the remarkable behavior of ovipositing only in recently burnt incense-cedar (''Calocedrus''), red cedar (''Thuja'') or juniper (''Juniperus''). The wood is often still smoldering while the wasp is laying its eggs, and the larvae develop in the wood. ''S. libocedrii'' occurs from the mountains of central California to southern British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ..., but is very rarely seen, except by firefighters. References Bibliography * Sawflies Insects described in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinothurioida
The Echinothurioida are an order of sea urchins in the class Echinoidea. Echinothurioids are distinguished from other sea urchins by the combination of a flexible test and hollow spines. The membrane around the mouth contains only simple plates, in contrast to the more complex mouth parts of their close relatives, the Diadematoida. They are nearly all deepsea dwellers. Characteristics Echinothurioids have regular tests (shells) with 10 columns of plates. These plates are fused in groups of three with a central primary plate and a half plate on either side. The edge of each group of plates overlaps the next one in the manner of tiles on a roof and this means the test is flexible. These animals usually collapse to a disc shape when brought to the surface. The primary tubercles which articulate with the spines are each perforated by a hole and the spines are hollow. The primary spines are usually long and are used to support the test and in locomotion. In many species, the seconda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurodidae
Jurodidae is a family of beetles that was originally described for the extinct genus '' Jurodes'', known from the Middle-Late Jurassic of Asia. In 1996, a living species, ''Sikhotealinia zhiltzovae'' was discovered in the Sikhote-Alin mountains in Siberia, and assigned to this family. Their placement is uncertain, but are usually considered archostematans. In one study, ''Sikhotealinia'' and ''Jurodes'' were considered a sister group to all other archostematan beetles. However, other authors have considered them to mix characteristics of Archostemata, as well as Polyphaga and Adephaga. Subdivision * '' Jurodes'' Ponomarenko 1985 **''Jurodes ignoramus'' Ponomarenko, 1985 Ichetuy Formation, Russia, Late Jurassic ( Oxfordian) ** ''Jurodes minor'' Ponomarenko, 1990 Glushkovo Formation, Russia, Late Jurassic (Tithonian) ** ''Jurodes daohugouensis'' Dahougou, China, Middle Jurassic (Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eomeropidae
Eomeropidae is a family of aberrant, flattened scorpionflies represented today by only a single living species, ''Notiothauma reedi'', known from the ''Nothofagus'' forests in southern Chile, while all other recognized genera in the family are known only as fossils, with the earliest definitive fossil known from Liassic-aged strata, and the youngest from Paleogene-aged strata.Archibald, S. Bruce, Alexandr P. Rasnitsyn, and Mikhail A. Akhmetiev. "Ecology and distribution of Cenozoic Eomeropidae (Mecoptera), and a new species of ''Eomerope'' Cockerell from the Early Eocene McAbee locality, British Columbia, Canada." Annals of the Entomological Society of America 98.4 (2005): 503-514. Genera There are six extinct genera and one monotypic living genus which have been placed in Eomeropidae. * †'' Eomerope''. Cockerell 1909 This genus is known from Paleogene fossils from Eocene and Oligocene strata of North America, including the Allenby Formation and the Florissant Formation, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mymarommatidae
The Mymarommatidae, sometimes referred to as false fairy wasps. are a very small family of microscopic parasitic wasps. Only about half of the known species are living taxa (the others are fossils), but they are found worldwide.Gibson, G.A.P.; Read, J.; Huber, J.T. (2007Diversity, classification and higher relationships of Mymarommatoidea (Hymenoptera).'Journal of Hymenoptera Research'' 16: 51–146 Little is known about the biology of these insects, but because of their size, and simple ovipositors, entomologists assumed they were idiobiont parasitoids on the eggs of insects, similar to other extremely small parasitic wasps such as fairyflies. Psocoptera, long suspected as their hosts based on circumstantial evidence, was confirmed to be the hosts of at least some mymarommatids in 2022, after specimens of ''Mymaromma menehune'' were observed emerging from the eggs of a member of the pscopteran family Lepidopsocidae.Honsberger DN, Huber JT, Wright MG (2022) A new ''Mymaromma'' sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glypheoidea
The Glypheoidea (containing the glypheoid lobsters), is a group of lobster-like decapod crustaceans which forms an important part of fossil faunas, such as the Solnhofen limestone. These fossils included taxa such as ''Glyphea'' (from which the group takes its name), and ''Mecochirus'', mostly with elongated (often semichelate) chelipeds. This group of decapods is a good example of a living fossil, or a lazarus taxon, since until their discovery in the 1970s, the group was considered to have become extinct in the Eocene. The superfamily Glypheoidea comprises five families. The two extant species, ''Neoglyphea inopinata'' and ''Laurentaeglyphea neocaledonica'', are both in the Glypheidae. Prehistoric abundance The first animals attributable to the Glypheoidea appeared in the Permo-Triassic. They were abundant in the Jurassic, but declined from the Cretaceous to the Eocene. Extant taxa The Glypheoidea was originally considered to be a purely fossil group. That opinion had to be a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dawn Redwood
''Metasequoia glyptostroboides'', the dawn redwood, is a fast-growing, endangered deciduous conifer. It is the sole living species of the genus ''Metasequoia'', one of three genera in the subfamily Sequoioideae of the family Cupressaceae. It now survives only in wet lower slopes and montane river and stream valleys in the border region of Hubei and Hunan provinces and Chongqing municipality in south-central China, notably in Lichuan county in Hubei. Although the shortest of the redwoods, it can grow to in height. In 1941, the genus ''Metasequoia'' was reported by paleobotanist Shigeru Miki as a widely distributed extinct genus based on fossils, before attracting considerable attention a few years later when small populations were found alive in central China. It is a particularly well-known example of a living fossil species. The tree faces considerable risks of extinction in its wild range due to deforestation, however it has been planted extensively in arboreta worldwide, wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelacanth
The coelacanths ( ) are fish belonging to the order Actinistia that includes two extant species in the genus ''Latimeria'': the West Indian Ocean coelacanth (''Latimeria chalumnae''), primarily found near the Comoro Islands off the east coast of Africa, and the Indonesian coelacanth (''Latimeria menadoensis''). The name "coelacanth" originates from the Permian genus ''Coelacanthus'', which was the first scientifically named coelacanth. Coelacanths follow the oldest-known living lineage of Sarcopterygii (lobe-finned fish and tetrapods), which means they are more closely related to lungfish and tetrapods (which includes amphibians, reptiles, birds and mammals) than to ray-finned fish. They are found along the coastline of Indonesia and in the Indian Ocean. The West Indian Ocean coelacanth is a critically endangered species. The oldest known coelacanth fossils are over 410 million years old. Coelacanths were thought to have become extinct in the Late Cretaceous, around 66 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
