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Pahvantia
''Pahvantia'' is an extinct genus of Hurdiidae, hurdiid Radiodonta, radiodont from the Cambrian period. It is known by a single species, ''Pahvantia hastata'', described from Wheeler Shale and Marjum Formation in Utah. Although it was once considered as a filter feeder based on the large number of putative setae on the frontal appendage, these structures were later interpreted as fossil material of the Trunk (anatomy), "trunk" section. Description File:20210516 Radiodonta head sclerites Pahvantia hastata.png, Head sclerites File:20210909 Radiodonta frontal appendage Pahvantia hastata.png, Frontal appendage (Radiodonta), Frontal appendage File:20210218 Pahvantia size.png, Size estimation ''Pahvantia'' is named after the Pahvant people of western Utah. It was originally described as a possible arthropod of unknown affinity (evolutionary relatives). One specimen was described as a specimen of ''Proboscicaris agnosta'', which was originally interpreted as a bivalved arthropod, but i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frontal Appendage (Radiodonta)
Radiodonta is an extinct Order (biology), order of stem-group arthropods that was successful worldwide during the Cambrian period. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and were used for a variety of functions. Radiodonts were among the earliest large predators, but they also included sediment sifters and filter feeders. Some of the most famous species of radiodonts are the Cambrian taxa ''Anomalocaris, Anomalocaris canadensis'', ''Hurdia, Hurdia victoria'', ''Peytoia nathorsti'', ''Titanokorys gainesii, Titanokorys gainesi, Cambroraster, Cambroraster falcatus'' and ''Amplectobelua, Amplectobelua symbrachiata''. The later surviving members include the subfamily Aegirocassisinae from the Early Ordovician of Morocco and the Early Devonian member ''Schinderhannes bartelsi'' from Germany. Etymology The name Radiodonta (Latin for ''radius'' "spoke of a wheel" and Greek for ''odoús'' "tooth") refers to the radial arrang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hurdiidae
Hurdiidae (synonymous with the previously named Peytoiidae) is an extinct cosmopolitan distribution, cosmopolitan Family (biology), family of radiodonts, a group of Crown group#Stem groups, stem-group marine arthropods, which lived during the Paleozoic Era. It is the most long-lived radiodont clade, lasting from the Cambrian period to the Devonian period. Description File:20191213 Radiodonta frontal appendage Hurdiidae.png, Anatomy of the frontal appendage of a hurdiid File:20191229 Radiodonta frontal appendage Hurdiidae.png, Frontal appendages of various species of hurdiid File:20200803 Radiodonta Hurdiidae H-element.png, Dorsal carapaces of various species of hurdiid Hurdiidae is characterized by Radiodonta#Frontal appendage, frontal appendages with distal region composed of 5 subequal blade-like endites, alongside the enlarged head carapaces and tetraradial mouthpart (Radiodonta#Oral cone, oral cone). The Radiodonta#Frontal appendage, frontal appendages of hurdiids have a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanokorys
''Titanokorys'' is a genus of extinct hurdiid (peytoiid) radiodont (a grouping of primitive stem arthropods which lived during the early Paleozoic) that lived during the Miaolingian epoch of the middle Cambrian. It is the largest member of its family from the Cambrian, with an estimated body length of around long, making it one of the largest animals of the time. It bears a resemblance to the related, and contemporary, genus ''Cambroraster''. Fossils of ''T. gainesi'' were first found within the Marble Canyon locality of the Burgess Shale in 2018, however the fossils were not named until 2021 because they were assumed to be giant specimens of ''Cambroraster''. The taxon is one of several genera of radiodonts known from the Burgess Shale, with some of the others being ''Cambroraster'', ''Anomalocaris'', ''Peytoia'', and ''Hurdia''. ''Titanokorys'' is distinguished from other Burgess Shale radiodonts because of its large anterior sclerite (head covering carapace, or H-element) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marjum Formation
The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah. It is named after its type locality, Marjum Pass, and was defined in 1908. The formation is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale, falling in the ''Ptychagnostus praecurrens'' trilobite zone. Fossil content Ambulacrarians Arthropods Chancelloriids Chordates Cnidarians Moon, Caron & Moysiuk (2023) considered these fossils would be ctenophores instead. Ctenophores Lophotrochozoans Scalidophorans Sponges See also * List of fossiliferous stratigraphic units in Utah * Paleontology in Utah References {{reflist Cambrian geology of Utah Cambrian southern paleotropical deposits Limestone formations of the United States Shale formations of the United States ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheeler Shale
The Wheeler Shale (named by Charles Walcott) is a Cambrian ( 507 Ma) fossil locality world-famous for prolific agnostid and ''Elrathia kingii'' trilobite remains (even though many areas are barren of fossils) and represents a Konzentrat-Lagerstätte. Varied soft bodied organisms are locally preserved, a fauna (including ''Naraoia'', ''Wiwaxia'' and ''Hallucigenia'') and preservation style ( carbonaceous film) normally associated with the more famous Burgess Shale. As such, the Wheeler Shale also represents a Konservat-Lagerstätten. Together with the Marjum Formation and lower Weeks Formation, the Wheeler Shale forms of limestone and shale exposed in one of the thickest, most fossiliferous and best exposed sequences of Middle Cambrian rocks in North America. At the type locality of Wheeler Amphitheater, House Range, Millard County, western Utah, the Wheeler Shale consists of a heterogeneous succession of highly calcareous shale, shaley limestone, mudstone and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drumian
The Drumian is a stage of the Miaolingian Series of the Cambrian. It succeeds the Wuliuan and precedes the Guzhangian. The base is defined as the first appearance of the trilobite '' Ptychagnostus atavus'' around million years ago. The top is defined as the first appearance of another trilobite '' Lejopyge laevigata'' around million years ago. GSSP The GSSP is defined in the ''Drumian section'' () in the Drum Mountains, Millard County, Utah, United States. The stage was also named after the Drum Mountains. The section is an outcrop of the Wheeler Formation, a succession of calcareous shales. The precise base of the Drumian is a laminated limestone above the base of the Wheeler Formation. Major events The Cambrian Drumian carbon isotope excursion (DICE) event is associated with the beginning of this age. The cause of this event was the shallowing of anoxic deep waters simultaneously with their transgression. DICE hampered the recovery of reef ecosystems already affected by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Feeder
Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a specialized filtering organ that sieves out and/or traps solids. Filter feeders can play an important role in condensing biomass and removing excess nutrients (such as nitrogen and phosphate) from the local waterbody, and are therefore considered water-cleaning ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms. Filter feeders can be sessile, planktonic, nektonic or even neustonic (in the case of the buoy barnacle) depending on the species and the niches they have evolved to occupy. Extant species that rely on such method of feeding encompass numerous phyla, including poriferans ( sponges), cnidarians (jellyfish, sea pens and corals), arthropods ( krill, mysids and barna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aegirocassis
''Aegirocassis'' is an extinct genus of giant radiodont arthropod belonging to the family Hurdiidae that lived 480 million years ago during the early Ordovician in the Fezouata Formation of Morocco. It is known by a single species, ''Aegirocassis benmoulai''. Van Roy initiated scientific study of the fossil, the earliest known of a "giant" filter-feeder discovered to date. ''Aegirocassis'' is considered to have evolved from early predatory radiodonts. This animal is characterized by its long, forward facing head sclerite, and the endites on its frontal appendages that bore copious amounts of baleen-like auxiliary spines. This animal evolving filter-feeding traits was most likely a result of the Great Ordovician Biodiversification Event, when environmental changes caused a diversification of plankton, which in turn allowed for the evolution of new suspension feeding lifeforms. Alongside the closely related '' Pseudoangustidontus'', an unnamed hurdiid from Wales, the middle Ordovi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nekton
Nekton or necton (from the ) is any aquatic organism that can actively and persistently propel itself through a water column (i.e. swimming) without touching the bottom. Nektons generally have powerful tails and appendages (e.g. fins, pleopods, flippers or jet propulsion) that make them strong enough swimmers to counter ocean currents, and have mechanisms for sufficient lift and/or buoyancy to prevent sinking. Examples of extant nektons include most fish (especially pelagic fish like tuna and sharks), marine mammals (cetaceans, sirenias and pinnipeds) and reptiles (specifically sea turtles), penguins, coleoid cephalopods (squids and cuttlefish) and several species of decapod crustaceans (specifically prawns, shrimps and krills). The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the planktons that were passively carried along by the current. As a guideline, nektonic organisms have a high Reynolds numbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tamisiocaris
''Tamisiocaris'' (from Latin ''tamisium'', sieve, and Greek ''karis'', crab, shrimp) is a radiodont genus from the Cambrian period. The taxon was initially described in 2010 based on frontal appendages discovered from the Sirius Passet lagerstatte in northern Greenland. A subsequent study by Vinther and colleagues in 2014 revealed that the frontal appendages were segmented and bore densely packed auxiliary spines, which were adapted to suspension feeding in a manner analogous to modern baleen whales. It is assigned to the family Tamisiocarididae, and is measured about long. Phylogeny ''Tamisiocaris'' in cladogram after Vinther ''et al''., 2014. References {{Taxonbar, from=Q2391651 Radiodonta Prehistoric arthropod genera Cambrian arthropods Cambrian Greenland Fossils of Greenland Sirius Passet fossils Buen Formation Fossil taxa described in 2010 Cambrian genus extinctions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
