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Anomalocaridid
Radiodonta is an extinct 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 canadensis'', '' Hurdia victoria'', ''Peytoia nathorsti'', '' Titanokorys gainesi, Cambroraster falcatus'' and '' 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 arrangement of tooth plates (oral cone) surrounding the mouth, although this feature i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomalocaris
''Anomalocaris'' (from Ancient Greek , meaning "unlike", and , meaning "shrimp", with the intended meaning "unlike other shrimp") is an extinct genus of radiodont, an order of early-diverging stem-group marine arthropods. It is best known from the type species ''A. canadensis,'' found in the Stephen Formation (particularly the Burgess Shale) of British Columbia, Canada. The other named species ''A. daleyae'' is known from the somewhat older Emu Bay Shale of Australia. Other unnamed ''Anomalocaris'' species are known from China and the United States. Like other radiodonts, ''Anomalocaris'' had swimming flaps running along its body, large compound eyes, and a single pair of segmented, frontal appendages, which in ''Anomalocaris'' were used to grasp prey. Estimated to reach long excluding the frontal appendages and tail fan, ''Anomalocaris'' is one of the largest animals of the Cambrian, and thought to be one of the earliest examples of an apex predator, though others have ... [...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] |
Arthropods
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metamerism (biology), metameric) Segmentation (biology), segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior Organ (anatomy), organs. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. They have ladder-like nervous systems, with paired Anatomical terms of location#Dorsal and ventral, ventral Ventral nerve cord, nerve cord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peytoia Nathorsti
''Peytoia'' is a genus of hurdiid radiodont, an early diverging order of stem-group arthropods, that lived in the Cambrian period, containing two species, ''Peytoia nathorsti'' from the Miaolingian of Canada and '' Peytoia infercambriensis'' from Poland, dating to Cambrian Stage 3. Its two frontal appendages had long bristle-like spines, it had no fan tail, and its short stalked eyes were behind its large head. 108 specimens of ''Peytoia'' are known from the Greater Phyllopod bed, where they comprise 0.21% of the community. ''Peytoia nathorsti'' and its junior synonym ''Laggania cambria'' played a major role in the discovery of the radiodont body plan. Initially interpreted as a jellyfish and a sea cucumber respectively, they were eventually shown to be the mouthparts and body of a single animal, which bore ''Anomalocaris''-like appendages. ''Peytoia infercambriensis'' is the geologically oldest known radiodont species. Classification ''Peytoia'' belongs to the clade Hurd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shucaris
''Shucaris'' ( ; meaning "Shu's shrimp") is a genus of radiodont of uncertain taxonomic placement from the Lower Cambrian Maotianshan Shales in Yunnan, South China. The type and only species is ''S. ankylosskelos'', known from multiple specimens comprising frontal appendages, multiple endites, gnathobase‐like structures, a nearly complete body, a head carapace complex, and one body flap associated with setal blades. Description ''Shucaris'' is known from multiple specimens which were all referred to ''S''. ''ankylosskelos'' by Wu ''et al.'' (2024). The holotype, JS-0972B, consists of an isolated frontal appendage. The paratypes, JS-1950 and JS-0658, comprise a nearly complete body specimen, and one partial disarticulated assemblage of a frontal appendage, gnathobase-like structures, an oral cone, portions of the head sclerites, and a flap associated with setal blades, respectively. Appendage morphology File:20240904_Radiodonta_frontal_appendage_Shucaris_ankylosskelos.png ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hurdia
''Hurdia'' is an extinct genus of Hurdiidae, hurdiid radiodont that lived 505 million years ago during the Cambrian Period. Fossils have been found in North America, China, and the Czech Republic. Taxonomic history ''Hurdia'' was named in 1912 by Charles Doolittle Walcott, Charles Walcott, with two species, the type species ''H. victoria'' and a referred species, ''H. triangulata''. The genus name refers to Mount Hurd. It is possible that Walcott had described a specimen the year prior as ''Amiella'', but the specimen is too fragmentary to identify with certainty, so ''Amiella'' is a ''nomen dubium''. Walcott's original specimens consisted only of H-elements of the frontal carapace, which he interpreted as being the carapace of an unidentified type of crustacean. P-elements of the carapace were described as a separate genus, ''Proboscicaris'', in 1962. In 1996, then-curator of the Royal Ontario Museum Desmond H. Collins erected the taxon Radiodonta to encompass ''Anomalocaris'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aegirocassisinae
Aegirocassisinae is a subfamily of radiodonts (marine stem-arthropods) from the lower Paleozoic era. It belongs to the larger hurdiidae (peytoiid) family, which were the most diverse and long lasting radiodonts. The members of this subfamily are restricted to the Lower Ordovician-aged Fezouata Formation of Morocco. Currently only two genera are included: ''Aegirocassis'' and '' Pseudoangustidontus''. These two genera possess large Baleen-like auxiliary spines on their frontal appendages, which suggests a suspension feeding lifestyle for the group. These radiodonts are some of the few known from sediments beyond the Cambrian period. This subfamily shows that following the Great Ordovician Biodiversification Event, which saw a rise in the plankton population in the worlds oceans, suspension feeding became more common in radiodonts then other feeding styles. It also seems that due to the evolution of new predators, like large nautiloid cephalopods, and other arthropod groups like the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomalocarididae
Anomalocarididae (occasionally mis-spelt Anomalocaridae) is an extinct family of Cambrian radiodonts, a group of stem-group arthropods. Around 1990s and early 2010s, Anomalocarididae included all radiodont species, hence the previous equivalent of the common name "anomalocaridid" to the whole Radiodonta. This is no longer the case after the revision done by Vinther et al. 2014, as Anomalocarididae restricted to only ''Anomalocaris ''Anomalocaris'' (from Ancient Greek , meaning "unlike", and , meaning "shrimp", with the intended meaning "unlike other shrimp") is an extinct genus of radiodont, an order of early-diverging stem-group marine arthropods. It is best known fro ...'' and, if any, a few of closely related genera since then. Wu et al. 2021 accepted only ''Anomalocaris'' (excluding '' "A." saron'', '' "A." kunmingensis'' and '' "A." briggsi'') and '' Lenisicaris'' as the member of Anomalocarididae, while '' Paranomalocaris'' is questionably included by some studies a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caryosyntrips
''Caryosyntrips'' (" nutcracker") is an extinct genus of stem-arthropod which known from Canada, United States and Spain during the middle Cambrian. It was first named by Allison C. Daley and Graham E. Budd in 2010, being the type species ''Caryosyntrips serratus''. Etymology The scientific name ''Caryosyntrips'' comes from Greek karyon, "nut"; and syntrips, "the smasher", a spirit from Greek mythology. Occurrence Multiple species had been recovered from the Burgess Shale Formation, Canada, Wheeler Shale and Marjum Formation, United States, and Valdemiedes Formation, Spain. The latter contain a large specimen, which was initially misidentified as a body remain of lobopodian ("''Mureropodia apae''"). While the assignment of “Mureropodia” as a misidentified appendage was controversial, the previous lobopodian affinity was less tenable than the fossil being a ''Caryosyntrips'' appendage. Description File:Pates & Daley 2017 f03.png, Fossil frontal appendages of ''C. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucumericrus
''Cucumericrus'' ("cucumber-leg") is an extinct genus of stem-arthropod. The type and only species is ''Cucumericrus decoratus'', with fossils discovered from the Maotianshan Shales of Yunnan, China. Description ''Cucumericrus'' known from a few poorly preserved specimens. Only fragments of trunk cuticle and corresponded appendages had been revealed, while important taxonomic features such as head structures are unknown. The trunk cuticle possess irregular wrinkles and may had been soft in life. Each of the trunk appendage compose of a dorsal flap-like element and a ventral stubby leg with unknown distal region, structurally comparable to the trunk appendages of gill lobopodians (dorsal flaps and ventral lobopods) and euarthropod biramous appendages (flap-like exopod and limb-like endopod). Anterior margin of the flap lined with ray-like structures, similar to the body flaps of some radiodonts. The legs have been interpreted as somewhere between annulated lobopod legs and segme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplectobelua
''Amplectobelua'' (meaning "embracing beast") is an extinct genus of late Early Cambrian amplectobeluid radiodont, a group of stem arthropods that mostly lived as free-swimming predators during the first half of the Paleozoic Era. Anatomy ''Amplectobelua'' was a giant radiodont, with the largest specimen of ''A. symbrachiata'' reaching up to in body length excluding the frontal appendages and tail. ''A. stephenensis'' is much smaller, estimated up to long. The body structures other than frontal appendages are only known from the type species ''Amplectobelua symbrachiata''. Like other radiodonts, ''Amplectobelua'' had a pair of jointed frontal appendages, a head covered by dorsal and lateral sclerites (the latter had been misinterpreted as huge eyes), a limbless body with dorsal gills (setal blades), and a series of flaps on both sides that extended along the length of its body. ''Amplectobelua'' had a specialized frontal appendage, in which it has a distinct 3-segmented s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tamisiocarididae
Tamisiocarididae is a family of Radiodonta, radiodonts, extinct marine animals related to arthropods, that bore finely-spined appendages that were presumably used in filter-feeding. When first discovered, the clade was named Cetiocaridae after a speculative evolution artwork, ''Bearded Ceticaris'' by John Meszaros, that depicted a hypothetical filter-feeding radiodont at a time before any were known to exist. However, the family name was not valid according to the International Code of Zoological Nomenclature, as no real genus named "Cetiocaris" exists, and in 2019 it was formally replaced by the name Tamisiocarididae, after the only valid genus of the clade at the time. The family is only known from Cambrian Series 2, Series 2 of the Cambrian, unlike other radiodont families, which persisted longer into the Cambrian. All known species would have lived in tropical or subtropical waters, suggesting a preference for warmer waters. Description Like most radiodonts, cetiocarids have s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
