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37-504: Depending on the author, various definitions and names for the members of the Khuff Formation have been proposed, which may lead to confusion. Vaslet et. al. (2005) defines the members as such (from oldest to youngest): The Al Siqqah Member is the oldest of the members, tentatively dated to the middle Permian ( Capitanian ). It is 35 meters thick at the type section, becoming thinner to the southeast. It has previously been referred to as

74-627: A "grasping and crushing array". Wear on some conodont elements suggests that they functioned like teeth, with both wear marks likely created by food as well as by occlusion with other elements. Studies have concluded that conodonts taxa occupied both pelagic (open ocean) and nektobenthic (swimming above the sediment surface) niches. The preserved musculature suggests that some conodonts ( Promissum at least) were efficient cruisers, but incapable of bursts of speed. Based on isotopic evidence, some Devonian conodonts have been proposed to have been low-level consumers that fed on zooplankton . A study on

111-723: A century. It has been hypothesized that the first mechanism of chordate tissue mineralization began either in the oral skeleton of conodonts or the dermal skeleton of early agnathans . The element array constituted a feeding apparatus that is radically different from the jaws of modern animals. They are now termed "conodont elements" to avoid confusion. The three forms of teeth, i.e., coniform cones, ramiform bars, and pectiniform platforms, probably performed different functions. For many years, conodonts were known only from enigmatic tooth-like microfossils (200 micrometers to 5 millimeters in length ), which occur commonly, but not always, in isolation and were not associated with any other fossil. Until

148-509: 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. Although conodont elements are abundant in the fossil record, fossils preserving soft tissues of conodont animals are known from only a few deposits in the world. One of the first possible body fossils of a conodont were those of Typhloesus , an enigmatic animal known from

185-637: A phylum with an ever-increasing number of subgroups. With increasingly strong evidence that conodonts lie within the phylum Chordata, more recent studies generally refer to "true conodonts" as the class Conodonta, containing multiple smaller orders. Paraconodonts are typically excluded from the group, though still regarded as close relatives. In practice, Conodonta, Conodontophorida, and Euconodonta are equivalent terms and are used interchangeably. Conodont elements consist of mineralised teeth-like structures of varying morphology and complexity. The evolution of mineralized tissues has been puzzling for more than

222-516: A proxy for thermal alteration in the host rock, because under higher temperatures, the phosphate undergoes predictable and permanent color changes, measured with the conodont alteration index . This has made them useful for petroleum exploration where they are known, in rocks dating from the Cambrian to the Late Triassic . The conodont apparatus may comprise a number of discrete elements, including

259-463: Is a simplified cladogram based on Sweet and Donoghue (2001), which summarized previous work by Sweet (1988) and Donoghue et al. (2000): Paraconodontida Cavidonti / Proconodontida Protopanderodontida Panderontida Paracordylodus Balognathidae Prioniodinida Ozarkodinida Only a few studies approach the question of conodont ingroup relationships from a cladistic perspective, as informed by phylogenetic analyses . One of

296-563: Is also the uppermost or latest of three subdivisions of the Guadalupian Epoch or Series . The Capitanian lasted between 264.28 and 259.51 million years ago. It was preceded by the Wordian and followed by the Wuchiapingian . A significant mass extinction event occurred at the end of this stage, which was associated with anoxia and acidification in the oceans and possibly caused by

333-650: Is located at Nipple Hill in the southern Guadalupe Mountains of Texas. The top of the Capitanian (the base of the Wuchiapingian and Lopingian series) is defined as the place in the stratigraphic record where the conodont species Clarkina postbitteri postbitteri first appears. The Capitanian Stage was part of the time in which the Zechstein was deposited in Europe. It is coeval with the old European regional Saxonian Stage. In

370-575: The Bear Gulch limestone in Montana . This possible identification was based on the presence of conodont elements with the fossils of Typhloesus . This claim was disproved, however, as the conodont elements were actually in the creature's digestive area. That animal is now regarded as a possible mollusk related to gastropods . As of 2023, there are only three described species of conodonts that have preserved trunk fossils: Clydagnathus windsorensis from

407-1073: The Carboniferous aged Granton Shrimp Bed in Scotland , Promissum pulchrum from the Ordovician aged Soom Shale in South Africa , and Panderodus unicostatus from the Silurian aged Waukesha Biota in Wisconsin . There are other examples of conodont animals that only preserve the head region, including eyes, of the animals known from the Silurian aged Eramosa site in Ontario and Triassic aged Akkamori section in Japan . According to these fossils, conodonts had large eyes, fins with fin rays, chevron-shaped muscles and axial line, which were interpreted as notochord or

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444-665: The Changhsingian and is about 60 meters thick in the Ad Dawadimi quadrangle. The Khartam Member (formerly the Khartam Limestone ) is the youngest member, with the lower part dating to the latest Permian and the upper part to the early Triassic . The Khuff Formation was deposited on the outer shelf of the Arabian Platform and represents a shallow carbonate platform , with a coastline oriented northeast-southwest and facing

481-467: The Unayzah Formation or Unayzah Member . The Huqayl Member has been dated to the late Permian (? Wuchiapingian ) based on foraminifer assemblage. It ranges from 30 to 40 meters in thickness. The Duhaysan Member is 13.4 meters thick at Jabal Duhaysan, and is believed to be late Permian ( Wuchiapingian - Changhsingian ) in age. The Midhnab Member (or Midhnab Shale ) is believed to date to

518-416: The class Conodonta . 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

555-428: The dorsal nerve cord . While Clydagnathus and Panderodus had lengths only reaching 4–5 cm (1.6–2.0 in), Promissum is estimated to reach 40 cm (16 in) in length, if it had the same proportions as Clydagnathus . The "teeth" of some conodonts have been interpreted as filter-feeding apparatuses, filtering plankton from the water and passing it down the throat. Others have been interpreted as

592-640: The Capitanian age show an increase in δ C values. The change in carbon isotopes in the sea water reflects cooling of global climates . This climatic cooling may have caused the end-Capitanian extinction event among species that lived in warm water, like larger fusulinids (Verbeekninidae), large bivalves ( Alatoconchidae ) and rugose corals, and Waagenophyllidae. 31°54′33″N 104°47′21″W  /  31.9091°N 104.7892°W  / 31.9091; -104.7892 Conodont Conodonts ( Greek kōnos , " cone ", + odont , " tooth ") are an extinct group of jawless vertebrates , classified in

629-844: The P-T extinction during the Early Triassic. Diversity continued to decline during the Middle and Late Triassic, culminating in their extinction soon after the Triassic-Jurassic boundary. Much of their diversity during the Paleozoic was likely controlled by sea levels and temperature, with the major declines during the Late Ordovician and Late Carboniferous due to cooler temperatures, especially glacial events and associated marine regressions which reduced continental shelf area. However, their final demise

666-839: The animals responsible for conodont fossils: Conodontophorida ("conodont bearers"). A few other scientific names were rarely and inconsistently applied to conodonts and their proposed close relatives during 20th century, such as Conodontophoridia, Conodontophora, Conodontochordata, Conodontiformes, and Conodontomorpha. Conodonta and Conodontophorida are by far the most common scientific names used to refer to conodonts, though inconsistencies regarding their taxonomic rank still persist. Bengtson (1976)'s research on conodont evolution identified three morphological tiers of early conodont-like fossils: protoconodonts , paraconodonts , and "true conodonts" (euconodonts). Further investigations revealed that protoconodonts were probably more closely related to chaetognaths (arrow worms) rather than true conodonts. On

703-508: The area was open to outside influence, and the conodont fauna confirms a shallow marine habitat. A large number of chondrichthyan dermal denticles are known from the formation. This article about the geography of Oman is a stub . You can help Misplaced Pages by expanding it . Capitanian In the geologic timescale , the Capitanian is an age or stage of the Permian . It

740-527: 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. The teeth-like fossils of the conodont were first discovered by Heinz Christian Pander and the results published in Saint Petersburg, Russia , in 1856. It was only in the early 1980s that

777-459: The broadest studies of this nature was the analysis of Donoghue et al. (2008), which focused on "complex" conodonts (Prioniodontida and other descendant groups): The earliest fossils of conodonts are known from the Cambrian period. Conodonts extensively diversified during the early Ordovician, reaching their apex of diversity during the middle part of the period, and experienced a sharp decline during

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814-409: The earliest conodont-like fossils, the protoconodonts , appear to form a distinct clade from the later paraconodonts and euconodonts . Protoconodonts are probably not relatives of true conodonts, but likely represent a stem group to Chaetognatha , an unrelated phylum that includes arrow worms. Moreover, some analyses do not regard conodonts as either vertebrates or craniates , because they lack

851-419: The early Guadalupian ( Roadian , Wordian ), led to an extended period of low diversity when worldwide two-thirds of terrestrial vertebrate life was lost. Global diversity rose dramatically in the Capitanian, probably the result of disaster taxa filling empty guilds, only to fall again when the end-Guadalupian event caused a diversity drop in the Wuchiapingian . Carbon isotopes in marine limestone from

888-526: The early 1980s, conodont teeth had not been found in association with fossils of the host organism, in a konservat lagerstätte . This is because the conodont animal was soft-bodied, thus everything but the teeth was unsuited for preservation under normal circumstances. These microfossils are made of hydroxylapatite (a phosphatic mineral). The conodont elements can be extracted from rock using adequate solvents. They are widely used in biostratigraphy . Conodont elements are also used as paleothermometers ,

925-524: The eastern Tethys domain , the Capitanian overlaps the regional Murgabian Stage, the Midian Stage and the lower part of the Laibinian Stage. In Russia the Capitanian equals the lower part of the regional Severodvinian Stage. The Capitanian contains one ammonite biozone ( Timorites ) and three conodont biozones: Larger fusulinid species permit a division in two biozones: Olson’s Extinction , in

962-469: The first fossil evidence of the rest of the animal was found (see below). In the 1990s exquisite fossils were found in South Africa in which the soft tissue had been converted to clay, preserving even muscle fibres. The presence of muscles for rotating the eyes showed definitively that the animals were primitive vertebrates. Through their history of study, "conodont" is a term which has been applied to both

999-506: The genus Panderodus have been speculated to be venomous, based on grooves found on some elements. As of 2012 , scientists classify the conodonts in the phylum Chordata on the basis of their fins with fin rays, chevron -shaped muscles and notochord . Milsom and Rigby envision them as vertebrates similar in appearance to modern hagfish and lampreys, and phylogenetic analysis suggests they are more derived than either of these groups. However, this analysis comes with one caveat:

1036-503: The individual fossils and to the animals to which they belonged. The original German term used by Pander was "conodonten", which was subsequently anglicized as "conodonts", though no formal latinized name was provided for several decades. MacFarlane (1923) described them as an order , Conodontes (a Greek translation), which Huddle (1934) altered to the Latin spelling Conodonta. A few years earlier, Eichenberg (1930) established another name for

1073-517: The late Ordovician and Silurian, before reaching another peak of diversity during the mid-late Devonian. Conodont diversity declined during the Carboniferous , with an extinction event at the end of the middle Tournaisian and a prolonged period of significant loss of diversity during the Pennsylvanian . Only a handful of conodont genera were present during the Permian, though diversity increased after

1110-474: The main characteristics of these groups. More recently it has been proposed that conodonts may be stem- cyclostomes , more closely related to hagfish and lampreys than to jawed vertebrates . Individual conodont elements are difficult to classify in a consistent manner, but an increasing number of conodont species are now known from multi-element assemblages, which offer more data to infer how different conodont lineages are related to each other. The following

1147-413: The other hand, paraconodonts are still considered a likely ancestral stock or sister group to euconodonts. The 1981 Treatise on Invertebrate Paleontology volume on the conodonts (Part W revised, supplement 2) lists Conodonta as the name of both a phylum and a class , with Conodontophorida as a subordinate order for "true conodonts". All three ranks were attributed to Eichenberg, and Paraconodontida

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1184-407: The population dynamics of Alternognathus has been published. Among other things, it demonstrates that at least this taxon had short lifespans lasting around a month. A study Sr / Ca and Ba /Ca ratios of a population of conodonts from a carbonate platform from the Silurian of Sweden found that the different conodont species and genera likely occupied different trophic niches . Some species of

1221-450: The spathognathiform, ozarkodiniform, trichonodelliform, neoprioniodiform, and other forms. In the 1930s, the concept of conodont assemblages was described by Hermann Schmidt and by Harold W. Scott in 1934. The feeding apparatus of ozarkodinids is composed of an axial Sa element at the front, flanked by two groups of four close-set elongate Sb and Sc elements which were inclined obliquely inwards and forwards. Above these elements lay

1258-461: The spreading Neotethys Ocean . The various units have been interpreted as lagoonal tidal sand flats or barrier beaches , outer-shelf conditions below storm wave base and deposition around storm wave base. The known fossil content supports the interpretation of the Khuff Formation as a marine environment . The presence of Tethyan brachiopods suggest a subtropical and warm climate, while cosmopolitan, endemic and Gondwanan brachiopod taxa indicate

1295-577: The volcanic eruptions that produced the Emeishan Traps . This extinction event may be related to the much larger Permian–Triassic extinction event that followed about 10 million years later. The Capitanian Stage was introduced into scientific literature by George Burr Richardson in 1904. The name comes from the Capitan Reef in the Guadalupe Mountains ( Texas , United States). The Capitanian

1332-481: Was also included as an order under Conodonta. This approach was criticized by Fåhraeus (1983), who argued that it overlooked Pander's historical relevance as a founder and primary figure in conodontology. Fåhraeus proposed to retain Conodonta as a phylum (attributed to Pander), with the single class Conodontata (Pander) and the single order Conodontophorida (Eichenberg). Subsequent authors continued to regard Conodonta as

1369-558: Was first used as a stratigraphic subdivision of the Guadalupian in 1961, when both names were still only used regionally in the southern US. The stage was added to the internationally used ICS timescale in 2001. The base of the Capitanian Stage is defined as the place in the stratigraphic record where fossils of conodont species Jinogondolella postserrata first appear. The global reference profile for this stratigraphic boundary

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