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Thulaspis Diagram
''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] |
Artiopoda
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 The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ... 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 elong ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidneyia Inexpectans
''Sidneyia'' is an extinct marine arthropod known from fossils found from the Early to the Mid Cambrian of China and the Mid Cambrian Burgess Shale of British Columbia, Canada. Description Sidneyia size comparison.svg, Size comparison of ''Sidneyia'' species Rsos211134f08 d.jpg, Biramous limb of ''Sidneyia inexpectans'' ''Sidneyia inexpectans'' reached lengths of at least . The largest known specimen of ''S. minor'' is around long and wide, while the largest specimen of ''S. malongensis'' is long and wide. The head shield is short, with notches present on the sides to accommodate stalked eyes, with the underside having a hypostome. The head has a pair of segmented antennae, as well as three pairs of post-antenal appendages. This was followed by a thorax, which had eight to ten segments/ tergites, each associated with a pair of biramous (two branched) appendages, this was followed with one to three abdomen segments/tergites, with the body terminating with a telson, which c ... [...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] |
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] |
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] |
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] |
20240212 Aglaspis Spinifer
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is a square number, the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures. Evolution of the Hindu-Arabic digit Brahmic numerals represented 1, 2, and 3 with as many lines. 4 was simplified by joining its four lines into a cross that looks like the modern plus sign. The Shunga would add a horizontal line on top of the digit, and the Kshatrapa and Pallava evolved the digit to a point where the speed of writing was a secondary concern. The Arabs' 4 still had the early concept of the cross, but for the sake of efficiency, was made in one stroke by connecting the "western" end to the "northern" end; the "eastern" end was finished off with a curve. The Europeans dropped the finishing curve and gradually made the digit less cursive, ending up with a digit very close to the original Brahmin cross. While the shape of the character for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aglaspidida
Aglaspidida is an extinct order of marine arthropods known from fossils spanning the Middle Cambrian to the Upper Ordovician. Initially considered chelicerates, modern anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within this group, and that they lie instead within the Artiopoda, thus placing them closer to the trilobites, being placed in the artiopod subgroup Vicissicaudata. With 38 known valid species as of 2017, they represent one of the most diverse groups of early Paleozoic arthropods, after trilobites.Lerosey-Aubril, R., Ortega-Hernández, J., Van Roy, P., Zhu, X., (2017)The Aglaspidida: a poorly-known, yet important order of early Palaeozoic arthropods ''International Workshop on Evolution of Cambrian Arthropods - Taxonomy, Ontogeny and Phylogeny''. 1-6 Sep. 2017, Xian, China. Aglaspidid fossils are found in North America (United States and Canada), Europe, Australia, and China. Description The exoskeletons of aglaspidids have frequently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eozetetes
''Eozetetes'' is a genus of vicissicaudatan artiopod from the Emu Bay Shale of Australia. It contains one species, ''Eozetetes gemmelli''. Description ''Eozetetes'' is roughly 3 cm long, with the tail spine making up half of this. The cephalic shield is semicircular with no genal spines and a relatively wide doublure. The hypostome is attached to the doublure, with a vaguely nose-like shape preserved extending most of the cephalic shield's length. Only one antenna is preserved, with it being long and flagelliform (whip-like) with only slight tapering. Several joints are preserved, with each segment roughly the same size. The trunk has 18 tergites (segments) with the second being widest. These tergites are distinctly three-lobed, with the axis being set apart by a break in the slope. The tergopleurae (part of the tergite which is not the axis) are broad with gently curved anterolateral margins and acute tips, which markedly narrow from the tenth tergite onwards alongside ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kodymirus Vagans
''Kodymirus'' is a genus of Early Cambrian arthropod, known from the Czech Republic. Although it possessed great appendage-like raptorial arms, it was not homologous with those of megacheirans. ''Kodymirus'' is currently considered a member of Vicissicaudata, closely related to aglaspidids, and more distantly to trilobites. It is part of a small and low-diversity Paseky Shale fauna group, which dwelt in brackish waters. Description ''Kodymirus'' was a small predator at long. Its distinctive feature is pair of large, serrated raptorial appendages. These appendages appear convergent to those of megacheirans and radiodonts, but are not homologous as they postantennular, suggesting raptorial arms evolved multiple times in Cambrian arthropods. Paleoecology ''Kodymirus'' inhabited the Paseky Shale, within the modern day Czech Republic, which may be a shallow marine environment or brackish estuary. Trace fossils from the Shale have been interpreted as ''Kodymirus'' raking ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kodymirus
''Kodymirus'' is a genus of Early Cambrian arthropod, known from the Czech Republic. Although it possessed great appendage-like raptorial arms, it was not homologous with those of megacheirans. ''Kodymirus'' is currently considered a member of Vicissicaudata, closely related to aglaspidids, and more distantly to trilobites. It is part of a small and low-diversity Paseky Shale fauna group, which dwelt in brackish waters. Description ''Kodymirus'' was a small predator at long. Its distinctive feature is pair of large, serrated raptorial appendages. These appendages appear convergent to those of megacheirans and radiodonts, but are not homologous as they postantennular, suggesting raptorial arms evolved multiple times in Cambrian arthropods. Paleoecology ''Kodymirus'' inhabited the Paseky Shale, within the modern day Czech Republic, which may be a shallow marine environment or brackish estuary. Trace fossils from the Shale have been interpreted as ''Kodymirus'' raking i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emeraldella Brutoni Reconstruction
''Emeraldella'' is a genus of arthropod known from the Middle Cambrian of North America. The type species ''E. brocki'' was described in 1912 from the Burgess Shale. 21 specimens of ''Emeraldella'' are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community. A re-study on the species was done in 2012. A second species ''E. brutoni'' is known from the Wheeler Shale, which was described in 2011. An additional specimen of ''E. brutoni'' was described in 2019, which revealed more of the anatomy. It has been placed as a basal member of the clade Vicissicaudata within Artiopoda, a group of arthropods containing trilobites and their relatives. Description [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
