Artiopoda
Artiopoda Temporal range:
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nektaspid
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cheloniellid
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
(unranked): | †Artiopoda Hou and Bergstrom, 1997 |
Subgroupings | |
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The Artiopoda is a grouping of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997[2] to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilobitomorpha. Trilobites, in part due to their mineralising exoskeletons, are by far the most diverse and long lived members of the clade, with most records of other members, which lack mineralised exoskeletons, being from Cambrian deposits.[3]
Description
According to Stein and Selden (2012) artiopods are recognised by the possession of
Taxonomy
Internal taxonomy
The Artiopoda have been considered by many studies to consist of two major clades; one reusing Trilobitomorpha to encompass trilobites, nektaspids, concilitergans and xandarellids, and the other called Vicissicaudata encompassing aglaspidids, xenopods and cheloniellids.[6] There are some taxa, such as Squamacula and the members of "Protosutura", which often are placed near the base of Artiopoda, outside the Vicissicaudata+Trilobitomorpha clade. These relationships are not always recovered.[7]
Relationships with other arthropods
The relationship of Artiopoda with the two major clades of modern arthropods, the Chelicerata and the Mandibulata, are unresolved, with some phylogenies recovering Artiopoda as more closely to chelicerates, forming the clade Arachnomorpha, while others recover Artiopoda as more closely related to mandibulates, forming the clade Antennulata.[8] Some studies place them as stem-group euarthropods, with mandibulates and chelicerates more closely related to each other than either is to Artiopoda.[7] Some studies have recovered a close relationship with Marrellomorpha, with the proposed clade including Artiopoda and Marrellomorpha dubbed Lamellipedia, though this relationship is not found in other analyses.[9][10] The enigmatic artiopodan-like arthropod Kiisortoqia, which bears large "frontal appendages" has been suggested to be closely related to Artiopoda in some analyses.[7]
Gallery
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Restoration of the trilobiteTriarthrus eatoni
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Fossils of Naraoia compacta (Nektaspida)
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Life restoration ofVicissicaudata)
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Diagram of Sinoburius (Xandarellida)
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Life restoration ofTrilobita)
Phylogeny
After Jiao et al. 2021.[11]
Artiopoda |
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References
- ^ .
- ^ Hou, X. & Bergström, J. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata, No. 45. Scandinavian University Press, Oslo, 22 Dec 1997: 116 pp.[1]
- . Retrieved 2022-07-29.
- S2CID 55018927.
- PMID 34330912.
- S2CID 85744103.
- ^ .
- S2CID 243269510.
- ISSN 0022-3360.
- .
- ISSN 0016-7568.