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Trilobitomorpha
Artiopoda is a clade of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997 to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilobitomorpha. Trilobites, in part due to abundance of findings owing to their mineralized exoskeletons, are by far the best recorded, diverse, and long lived members of the clade. Other members, which lack mineralised exoskeletons, are known mostly from Cambrian deposits. Description According to Stein and Selden (2012) artiopods are recognised by the possession of filiform antennulae, limbs with bilobate exopods (upper branches), with the proximal (closest to base of the limb) lobe being elongate and bearing a lamella, while the distal (further from the limb base) lobe is paddle-shaped and setiforous (bearing hair-or bristle like structures). The limb endopod (inner, leg-like branch) has seven podomeres/segments, with first four podomeres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pygmaclypeatus
''Pygmaclypeatus'' is a genus of trilobite-like arthropod from the Cambrian aged Chengjiang biota of southern China. The carapace is flat and broad, and slightly shorter than it is wide, reaching a maximum width of and length of . The headshield makes up about 25% of the total length, and has attached a pair of antennae, as well as a pair of unstalked eyes on the top of the headshield and pair of stalked eyes attached to the underside. The headshield also has four pairs of biramous (two branched) limbs. The trunk has 6 tergites (segments), each associated with a pair of biramous limbs along with a terminal pygidium associated with four pairs of biramous appendages and a segmented short tailspine. The well developed paddle-like exopodites (upper branch) on the trunk and pygidium limbs along with its small size suggests that it was an effective swimmer with a strong power stroke, and that it probably had a nektobenthic mode of life, swimming close to the ocean floor. Given its d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bailongia
''Bailongia'' is an extinct genus of arthropod known from a single species ''Bailongia longicaudata'' (''longicaudata'' from Latin: "long-tailed") found in the Cambrian Stage 4 aged Maotianshan Shales, Guanshan Biota of Yunnan, China. It was around 5mm long and had a large head shield, nine overlapping tapering tergites and a relatively elongate tailspine. It has been recovered in a relatively Basal (phylogenetics), basal position within Artiopoda, more derived than ''Squamacula'' or Protosutura, but outside Trilobitomorpha or Vicissicaudata. Phylogeny After Jiao et al. 2021. References Artiopoda Cambrian arthropods of Asia Cambrian China Paleontology in Yunnan Fossil taxa described in 2021 Cambrian genus extinctions {{Paleo-arthropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retifacies
''Retifacies abnormalis'' is an extinct arthropod that lived in the lower Cambrian (about 518 million years ago). Its fossil remains have been found in the Maotianshan Shales of Yunnan, China. It is a member of the Artiopoda, and closely related to ''Pygmaclypeatus''. Description ''Retifacies'' was relatively large sized, reaching a carapace length of , and a total length of , including the extended Antenna (zoology), antennae and tailspine. The head shield was broad and short, and appears to have lacked eyes. The antennae had 17 segments, which telescoped into each other, with spines present on the underside of the antennae at the boundary between the segments. Also present on the head were four closely spaced pairs of appendages, the first three of which were uniramous (single branched), while the last was biramous (two branched). The three uniramous appendages had six segments (podomeres), each ending with a terminal claw, with the endopod (lower leg-like branch) of the fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xandarellida
Xandarellida is an extinct order of artiopod arthropods known exclusively from the Middle Cambrian of China and Siberia. Morphology In terms of anatomy, xandarellids share numerous characteristics such as a natant hypostome, alongside a unique feature known as “segment decoupling” where the amount of limbs exceeds the amount of tergites. They also share a posteriorly extended semicircular head shield and ventral stalked eyes. The genus '' Cindarella'' in particular has complex eyes, with over 2000 ommatidia in each. ''Cindarella'' also has a large anterior spine on the fifteenth tergite. '' Xandarella'' has an unusual tripartite head shield, with ventral eye slits likely retained from the ancestral stalked eyes, alongside possibly lacking the anterior spine. '' Phytophilaspis'' has an especially intricate head shield, sharing its tripartite nature with ''Xandarella'' alongside bearing several sutures all over its body and seemingly having almost completely fused tergites. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conciliterga
Conciliterga is an extinct order of artiopod arthropods, exclusively known from the Middle Cambrian. They are placed within the clade Trilobitomorpha, which contains the trilobites and their closest relatives. Conciliterga is united by their partially or wholly fused tergites, which gives rise to their name (Conciliterga is composed of the Latin words ''concilio'' ("to unite") and ''tergum'' ("back")). Most members of this clade are elliptical in body shape, with 6-9 thoracic tergites, a head shield and a large tail shield in the members with incomplete tergite fusion. These members, which formerly comprised the order Helmetiida (which currently only contains ''Helmetia'', '' Rhombicalvaria'' and '' Kuamaia''), also have various other characteristics like a lack of axial region, rostral and pararostral plates on the head, and compound eyes near the rostral plate. In addition, they have essentially uniform biramous limbs running down the body with coarse endopods, alongside a pair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nektaspid
Nektaspida (also called Naraoiida, Nektaspia and Nectaspida) is an extinct order of non- mineralised artiopodan arthropods. They are known from the lower-Cambrian to the upper Silurian. Originally classified as trilobites, which they superficially resemble, they are now placed as close relatives as members of the Trilobitomorpha within Artiopoda. The order is divided into three major families; Emucarididae, Liwiidae, and Naraoiidae. Naming history and taxonomic placement The order was originally proposed by Raymond in 1920 as Nektaspia. Størmer corrected it to Nectaspida for the 1959 ''Treatise on Invertebrate Paleontology'' to conform with the names of the other trilobite orders. Whittington described it in 1985 with the spelling Nektaspida; the revised 1997 Treatise by Raymond and Fortey uses this spelling, as do other modern works. Whittington (1985) placed the order in the Trilobita. Cotton & Braddy (2000) place it in a new "Trilobite clade" containing the Trilobita, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kwanyinaspis
''Kwanyinaspis'' is a genus of arthropod from the Cambrian aged Chengjiang biota of Yunnan, China. It was described in 2005 based on a single specimen, ELI-2004001. Around 6 cm long, It has twelve trunk tergites with well developed posterior facing pleural spines, along with a tail spine and ventral eyes. In the original description, it was tenatively considered a member of Aglaspidida. However, later studies have considered it a trilobitomorph, and possibly the closest known relative of trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...s. References {{Taxonbar, from1=Q113427154 Artiopoda Prehistoric arthropod genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthroaspis
''Arthroaspis'' is an extinct genus of arthropod known from the Cambrian aged Sirius Passet Lagerstatte in Greenland. It is relatively large in size for Cambrian arthropods, attaining a length of up to 215 mm. It is a common component of the Passet fauna, being located at multiple localities within the formation. It possessed 14 tergites. In the describing paper, it was recovered as a member of a non-monophyletic Artiopoda. It has subsequently been considered a potential close relative of nektaspids. Another paper from 2025 which re-analyzed the Burgess Shale artiopod '' Helmetia expansa'', found ''Arthroaspis'' to be a basal member of the Conciliterga, within the Trilobitomorpha Artiopoda is a clade of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997 to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilobitomor .... References {{Taxonbar, from=Q96372401 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zhiwenia
''Zhiwenia'' is a genus of artiopods that existed during Stage 3 of the Cambrian period and was uncovered in the Xiaoshiba Lagerstätte in China. Only one species is known, ''Zhiwenia coronata''. It is the sister taxon of '' Australimicola'' in the newly defined clade Protosutura, which is itself the sister group of Trilobitomorpha Artiopoda is a clade of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997 to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilobitomor .... References Cambrian arthropods of Asia Artiopoda {{Paleo-arthropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobita
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nektaspida
Nektaspida (also called Naraoiida, Nektaspia and Nectaspida) is an extinct order of non- mineralised artiopodan arthropods. They are known from the lower-Cambrian to the upper Silurian. Originally classified as trilobites, which they superficially resemble, they are now placed as close relatives as members of the Trilobitomorpha within Artiopoda. The order is divided into three major families; Emucarididae, Liwiidae, and Naraoiidae. Naming history and taxonomic placement The order was originally proposed by Raymond in 1920 as Nektaspia. Størmer corrected it to Nectaspida for the 1959 ''Treatise on Invertebrate Paleontology'' to conform with the names of the other trilobite orders. Whittington described it in 1985 with the spelling Nektaspida; the revised 1997 Treatise by Raymond and Fortey uses this spelling, as do other modern works. Whittington (1985) placed the order in the Trilobita. Cotton & Braddy (2000) place it in a new "Trilobite clade" containing the Trilobita, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thulaspis
''Thulaspis'' is an extinct genus of artiopodan arthropod from the Cambrian Stage 3 aged Sirius Passet site in Greenland. It is thought to be a close relative of '' Squamacula'', and is possibly one of the most basal members of Artiopoda. Description ''Thulaspsis'' was relatively large-sized. The largest specimen is about wide and long. The carapace is overall oval-shaped was convex and likely stiff in life, with a raised central axis. The head is broad and bears a pair of antennae, which have at least 20 rectangular segments, and likely two pairs of biramous (two branched) limbs.The body has 15 thoracic segments, which curve forwards in the first few segments, before becoming straight in the fourth and fifth segments, then increasingly posteriorly curved in subsequent segments. At least the first 11 thoracic segments are associated with pairs of biramous limbs. The biramous limbs have robust endopods (lower, leg-like branches), and flap-shaped exopods (upper branches). The b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
