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Conodonts
Conodonts, are an extinct group of marine jawless vertebrates belonging to the Class (biology), class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning "cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard, mineralised tooth-like structures called "conodont elements" that in life were present in the oral cavity and used to process food. Rare soft tissue remains suggest that they had elongate eel-like bodies with large eyes. Conodonts were a long-lasting group with over 300 million years of existence from the Cambrian (over 500 million years ago) to the beginning of the Jurassic (around 200 million years ago). Conodont elements are highly distinctive to particular species and are widely used in biostratigraphy as indicative of particular periods of geological time. Discovery and understanding of conodonts The teeth-like fossils of the conodont were first discovered by Heinz Christian Pander and the results published in Sain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proconodontida
Proconodontida is an Order (biology), order of conodonts which originated in the late Cambrian (Furongian) and persisted partly through the Ordovician. The ancestral proconodont, ''Proconodontus'', was one of the earliest euconodonts ("true conodonts") to appear. Proconodonts are often equated with the broader group Cavidonti, which occupies one side of a basal division in the evolution of early euconodonts in the Cambrian. All other euconodonts occupy Conodonti, the other side of the Cambrian split. Proconodontida may be ancestral to another order, Belodellida. Belodellids originate in the Ordovician and survive up to the Devonian or even the Permian (if ''Caenodontus'' qualifies as a member of the order). Description Cavidonts were simple conodonts, tending to maintain smooth and thin-walled elements with a hyaline structure. They were often coniform (horn- or tooth-shaped) with a semi-symmetrical or elliptical cross-section. The basal cavity was deeper than in early members ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belodellida
Proconodontida is an order of conodonts which originated in the late Cambrian ( Furongian) and persisted partly through the Ordovician. The ancestral proconodont, '' Proconodontus'', was one of the earliest euconodonts ("true conodonts") to appear. Proconodonts are often equated with the broader group Cavidonti, which occupies one side of a basal division in the evolution of early euconodonts in the Cambrian. All other euconodonts occupy Conodonti, the other side of the Cambrian split. Proconodontida may be ancestral to another order, Belodellida. Belodellids originate in the Ordovician and survive up to the Devonian or even the Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ... (if '' Caenodontus'' qualifies as a member of the order). Description Cavidonts were s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraconodontida
Paraconodonts (Paraconodontida) are an extinct order of probable chordates, closely related or ancestral to euconodonts (true conodonts Conodonts, are an extinct group of marine jawless vertebrates belonging to the Class (biology), class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning "cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known ...). The order contains the superfamily Furnishinacea'','' itself containing the families Westergaardodinidae and Furnishinidae.'''' Paraconodonts were introduced into the scientific literature by Klaus Müller, who sought out the Cambrian ancestors of conodonts through the 1950s and 1960s and proclaimed success upon the discovery of paraconodont fossils. Like early true conodonts, paraconodont elements were phosphatic fossils which generally had a horn- or tooth-like shape, and some were serrated with multiple cusps. '' Westergaardodina'' acquired an even more unusual W- or horseshoe-shaped for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jawless Vertebrates
Agnatha (; ) or jawless fish is a paraphyletic infraphylum of animals in the subphylum Vertebrata of the phylum Chordata, characterized by the lack of jaws. The group consists of both extant taxon, living (Cyclostomi, cyclostomes such as hagfishes and lampreys) and Extinction, extinct clades (e.g. conodonts and Cephalaspidomorphi, cephalaspidomorphs, among others). They are sister taxon, sister to vertebrates with jaws known as gnathostomes, who evolution, evolved from jawless ancestors during the early Silurian by developing folding joint, articulations in the first pairs of gill arches. Sequencing, Molecular data, both from rRNA and from mtDNA as well as Embryology, embryological data, strongly supports the hypothesis that both groups of living agnathans, hagfishes and lampreys, are more closely related to each other than to Gnathostomata, jawed fish, forming the Class (biology), superclass Cyclostomi. The oldest fossil agnathans appeared in the Cambrian. Living jawless fish c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protopanderodontida
Protopanderodontida is an order of conodonts which lived from the Furongian (Late Cambrian) to the Wenlock (mid-Silurian). They had a relative simple apparatus with several pairs of coniform elements (single-cusped tooth-like structures) in the mouth, lacking the more elaborate arrangements found in "complex conodonts" ( Prioniodontida). Protopanderodontids were a common component of Ordovician conodont faunas, and were probably a grade ancestral to later conodonts in the orders Panderodontida and Prioniodontida. They may have been the earliest conodonts with an odd number of elements in the jaw. A single median symmetrical element (the S0 element) is found at the midline of the apparatus, potentially originating from a fusion of paired coniform elements in an earlier ancestor. The only putative protopanderodontid to preserve an articulated partial apparatus is '' Besselodus arcticus'', from the Late Ordovician of Greenland. Taxonomy Sweet (1988) named both Protopanderodon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prioniodinida
Prioniodinida is an extinct order of conodonts, a jawless vertebrate. Families Families are: * †Bactrognathidae * † Chirognathidae * † Ellisoniidae * † Gondolellidae * † Prioniodinidae References * Sweet, W. C; P. C.J Donoghue (2001). "Conodonts: past, present, future". Journal of Paleontology 75 (6): 1174. External links * Prioniodinida at biolib.cz(retrieved 22 April 2016) Prioniodinidaat fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ....org (retrieved 22 April 2016) † {{Conodont-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinz Christian Pander
Heinz Christian Pander, also Christian Heinrich Pander ( Russian: Христиан Иванович Пандер; – ) was a Russian biologist and embryologist of Baltic German origin. Biography In 1817 he received his doctorate from the University of Würzburg, and spent several years (1827–1842), performing scientific research from his estate in Carnikava () on the banks of the Gauja River near Riga. In 1820 he took part in a scientific expedition to Bokhara as a naturalist. In 1826 he became a member of the Saint Petersburg Academy of Sciences. Research Pander studied the chick embryo and discovered the germ layers (i.e., three distinct regions of the embryo that give rise to the specific organ system). Because of these findings, he is considered by many to be the "founder of embryology". His work in embryology was continued by Karl Ernst von Baer (1792-1876), who expanded Pander's concept of germ layers to include all vertebrates. Pander performed important stud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoconodont
Protoconodonts are an extinct group of Cambrian animals known from fossilized phosphatic tooth-like structures. They were originally described as an informal group of early conodonts, though more recent studies consider them to be more closely related to chaetognaths (arrow worms). Protoconodont elements are slender and pointed, with a hollow interior which opens towards the base of the structure. They develop entirely by the addition of layers to the inner cavity, extending the rim of the base. There is no additional mineralization on the outer surface, in contrast to paraconodonts or euconodonts (true conodonts). Protoconodont elements are frequently found bundled together into a 'superteeth', paired claw-like clusters which may have had a grasping function. These 'superteeth' were previously known by the name ''"Prooneotodus" tenuis'', now classified as a species of '' Phakelodus''.'''' A few protoconodont genera were previously assigned to the class Conodonta and the order P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prioniodontida
Prioniodontida, also known as the "complex conodonts", is a large clade of conodonts that includes two major evolutionary grades; the Prioniodinina and the Ozarkodinina. It includes many of the more famous conodonts, such as the giant ordovician '' Promissum'' (Prioniodinina) from the Soom Shale and the Carboniferous specimens from the Granton Shrimp bed (Ozarkodinina). They are euconodonts, in that their elements are composed of two layers; the crown and the basal body, and are assumed to be a clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t .... Phylogeny This is a recent cladogram of the Prioniodontida, simplified from Donoghue ''et al.'', (2008). Notes References {{Taxonbar, from=Q6581502 Vertebrate unranked clades ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozarkodinida
Ozarkodinida is an extinct conodont order. It is part of the clade Prioniodontida, also known as the "complex conodonts". Name Ozarkodinida is named after the Ozark Mountains of Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ..., United States. Elements The feeding apparatus of ozarkodinids is composed at the front of an axial Sa element, flanked by two groups of four close-set elongate Sb and Sc elements which were inclined obliquely inwards and forwards. Above these elements lay a pair of arched and inward pointing (makellate) M elements. Behind the S-M array lay transversely oriented and bilaterally opposed (pectiniform, i.e. comb-shaped) Pb and Pa elements. References External links * * † {{Conodont-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Cambrian
Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (other) * Middle Brook (other) * Middle Creek (other) * Middle Island (other) * Middle Lake (other) * Middle Mountain, California * Middle Peninsula, Chesapeake Bay, Virginia * Middle Range, a former name of the Xueshan Range on Taiwan Island * Middle River (other) * Middle Rocks, two rocks at the eastern opening of the Straits of Singapore * Middle Sound, a bay in North Carolina * Middle Township (other) * Middle East Music *Middle (song), "Middle" (song), 2015 *The Middle (Jimmy Eat World song), "The Middle" (Jimmy Eat World song), 2001 *The Middle (Zedd, Maren Morris and Grey song), "The Middle" (Zedd, Maren Morris and Grey song), 2018 *"Middle", a song by Rocket from the Crypt from their 1995 album ''Scream, Dracula, Scream!'' *"The Middle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jan Zalasiewicz
Jan Zalasiewicz (born 1954 in Manchester) is a British-Polish geologist and palaeontologist, emeritus professor at the University of Leicester, and Ig Nobel laureate. Life His parents escaped from Siberia with the Anders' Army. He was the head of the Anthropocene Working Group The Anthropocene Working Group (AWG) is an interdisciplinary research group dedicated to the study of the Anthropocene as a geological time unit. It was established in 2009 as part of the Subcommission on Quaternary Stratigraphy (SQS), a constitu ... from 2009 to 2020. Publications * The Earth After Us (2008), . * The Planet in a Pebble: A Journey Into Earth's Deep History (2012) * The Cosmic Oasis: The Remarkable Story of Earth's Biosphere (2022), with Mark Williams References External links Zalasiewicz's page at the University of Leicester. Jan Zalasiewicz on the Age of Man – interview from January 17, 2017 on BBC Radio 4. * Correspondence to „The Palaeontological Association” . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
