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Emeraldella
''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] |
Vicissicaudata
Vicissicaudata is an unranked group of artiopodan arthropods, containing Cheloniellida, Aglaspidida and several other genera outside these groups like ''Sidneyia'' and ''Emeraldella.'' Description Vicissicaudatans are similar to most other artiopods in shape, with rounded bodies consisting of many wide tergites, sometimes with a distinguishable axis along the midline. This clade is defined by a differentiated posterior region, often ending in a telson and caudal appendages. The morphology of this posterior region varies between clades. Aglaspidids, alongside '' Eozetetes'' and '' Carimersa'', have long styliform telsons and relatively small, flap-like caudal appendages while cheloniellids and '' Tardisia'' have much longer caudal appendages similar to the caudal furcae of various taxa, alongside much smaller telsons more resembling the postabdominal segments. The paraphyletic "xenopods" are more similar to those of aglaspidids, also with long telsons and flap-like caudal app ... [...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] |
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] |
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] |
Carimersa Neptuni
''Carimersa'' is an extinct genus of artiopodan arthropod known from the Silurian Coalbrookdale Formation of Herefordshire, England. Description The body is flattened, and divided into the head with five pairs of paired appendages, the trunk with 10 appendage-bearing segments, a limbless abdomen with 4 segments, with the body terminating with tailspine. The total length of the body excluding the tailspine is around , with a max width of about . The first antennae-like head appendage bears three flagellae-like structures. The second and third head appendages are uniramous and have basipods (basal segments) modified into spined gnathobases (used to process food). The last two head appendages and the trunk limbs are biramous, and have robust endopods that bear spines, with the exopods being flap-like and reinforced by a rod-like structure. Ecology ''Carimersa'' was likely an actively swimming organism that probably swam close to the sediment surface. The presence of associat ... [...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] |
