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Austrolimulidae
Austrolimulidae is an extinct family of Xiphosura, horseshoe crabs belonging to the infraorder Limulina. Members of the family are known from the Permian to the beginning of the Jurassic, though one species has been reported from the end of the Cretaceous. Austrolimulids are known for amongst the most extreme morphologies among Xiphosurids, including large elongated genal spines. Unlike living Limulids, Austrolimulids were likely adapted for freshwater and brackish environments. They are considered to be the sister group to Limulidae, the group that contains all modern horseshoe crabs. Genera * †''Austrolimulus'' Riek, 1955 Triassic, Beacon Hill Shale, NSW, Australia * †''Attenborolimulus'' Bicknell, 2021 Triassic (Olenekian), Petropavlovka Formation, Cis-Urals, Russia * †''Batracholimulus'' Wilde, 1987 Triassic (Rhaetian), Exter Formation, Germany * †''Boeotiaspis'' Lamsdell, 2020 Carboniferous, United States (Jr. synonym) * †''Casterolimulus'' Holland, Erickson & O' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphosura
Xiphosura () is an order of arthropods related to arachnids. They are more commonly known as horseshoe crabs (a name applied more specifically to the only extant family, Horseshoe crab, Limulidae). They first appeared in the Hirnantian (Late Ordovician). Currently, there are only four living species. Xiphosura contains one suborder, Xiphosurida, and several stem-genera. The group has hardly changed in appearance in hundreds of millions of years; the modern horseshoe crabs look almost identical to prehistoric genera and are considered to be living fossils. The most notable difference between ancient and modern forms is that the abdominal segments in present species are fused into a single unit in adults. Xiphosura were historically placed in the class Merostomata, although this term was intended to encompass also the Eurypterida, eurypterids, whence it denoted what is now known to be an unnatural (paraphyletic) group (although this is a grouping recovered in some recent cladistic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Austrolimulus
''Austrolimulus fletcheri'' is an extinct xiphosuran, related to the modern horseshoe crab. The holotype and only known specimen is from Middle Triassic-aged strata of Brookvale, New South Wales of Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ....Riek, E. F. "A NEW XIPHOSURAN FROM THE TRIASSIC SEDIMENTS AT BROOKVALE, NEW SOUTH WALES." Records of the Australian Museum 23 (1955): 281-282/ref> References *''Evolution: What the Fossils Say and Why It Matters'' by Donald R. Prothero and Carl Buell External linksXiphosuraat Palaeos.com Xiphosura Middle Triassic arthropods {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lueders Formation
The Lueders Formation is a geologic formation in Texas. It is the top formation of the Albany Group and preserves fossils dating back to the Permian period. Description Paleogeography At the time of deposition, a broad sea connected to the Panthalassic Ocean covered much of the central United States, including Texas. The Lueders Formation would have been located in the northern tropics or subtropics. Climatically, after the retreat of an early Artinskian glacial maximum, the deserts of the North American craton experienced fluctuation and growth during this time period, and the associated aridity decrease impacted seabed deposition in localities across the basin. Depositional environment The Lueders Formation represents a deltaic environment, with terrestrial sediments being deposited onto the muddy bottom of a shallow estuary by shifting freshwater streams. In the Maybelle Member, the dolomite likely represents marine deposits, preserving marine sharks and fish, whereas dar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kungurian
In the geologic timescale, the Kungurian is an age or stage of the Permian. It is the latest or upper of four subdivisions of the Cisuralian Epoch or Series. The Kungurian lasted between and million years ago (Ma). It was preceded by the Artinskian and followed by the Roadian. It corresponds roughly to the Leonardian Stage, covering the span from 280 to 270.6 ± 0.7 Ma in the North American system. Stratigraphy The Kungurian is named after the Russian city of Kungur in Perm Krai. The stage was introduced into scientific literature by Russian geologist Alexandr Antonovich Stukenberg (Alexander Stuckenberg) in 1890.; 2002: ''Progress report on the base of the Artinskian and base of the Kungurian by the Cisuralian Working Group'', Permophiles 41: pp 13–16. The base of the Kungurian Stage is defined as the place in the stratigraphic record where fossils of conodont species ''Neostreptognathodus pnevi'' and ''Neostreptognathodus exculptus'' first appear. As of 2009, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limulitella
This list of xiphosurans is a comprehensive listing of all genera that have ever been included in the order Xiphosura, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (''nomen dubium''), or were not formally published (''nomen nudum''), as well as junior synonyms of more established names, genera that are no longer considered xiphosurans and misspellings. The list currently includes 54 names out of which 31 are considered valid xiphosuran genera. As of 2019, there were around 80 extinct species of xiphosurans and 4 extant species of xiphosurans recognized as valid. Naming conventions and terminology There is no "official" or "canonical" list of xiphosuran genera. The closest thing is found contained in the regularly updated ''Summary list of fossil spiders and their relatives'' in the World Spider Catalog, which include just the extinct species. The vast majority or all of the content of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hettangian
The Hettangian is the earliest age and lowest stage of the Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ... Geological time scale, Period of the geologic timescale. It spans the time between 201.3 ± 0.2 annum, Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triassic Period) and is followed by the Sinemurian. In European stratigraphy the Hettangian is a part of the time span in which the Lias Group, Lias was deposited. An example is the British Blue Lias, which has an upper Rhaetian to Sinemurian age. Another example is the lower Lias from the Northern Limestone Alps where well-preserved but very rare ammonites, including Alsatites, have been found. Stratigraphic definitions The Hettangian was introduced in the literature by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Napperby Formation , a pastoral lease in Northern Territory, Australia
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Napperby may refer to: *The Napperby Block, a parcel of land forming part of the Wapma Thura–Southern Flinders Ranges National Park since late 2021 * Napperby, South Australia, a locality in South Australia *Napperby Station Napperby Station, also known as Napperby, is a pastoral lease used as a cattle station in the Northern Territory of Australia. History The station was established on Anmatyerre tribal land. The Chisholm family have owned Napperby Station "on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Epoch) and precedes the Ladinian Age. Stratigraphic definitions The stage and its name were established by Austrian geologists Wilhelm Heinrich Waagen and Carl Diener in 1895. The name comes from ''Anisus'', the Latin name of the river Enns. The original type locality is at Großreifling in the Austrian state of Styria. The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of conodont species '' Chiosella timorensis'' in the stratigraphic record. Other stratigraphers prefer to use the base of magnetic chronozone MT1n. There is no accepted global reference profile for the base, but one ( GSSP or golden spike) was proposed at a flank of the mountain Deşli Caira in the Roman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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