Xenusia
| Xenusiids Temporal range: Early Cambrian to Carboniferous |
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| Hallucigenia sparsa | |
| Scientific classification | |
| Kingdom: | Animalia |
| Superphylum: | Ecdysozoa |
| Phylum: | †"Lobopodia" |
| Class: |
†Xenusia Dzik & Krumbiegel, 1989 |
| Orders | |
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See text. |
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See text.
Class Xenusia, the Xenusiids, represents the subset of lobopodian worms that fall in the stem-lineage of Onychophora. Their type genus is Xenusion. They have relatively large, annulated, cylindrical bodies. Their lobopod legs have tubercles at their bases. Some have large frontal appendages, although these may represent taphonomic artefacts. Their mouth is terminal or subterminal, and they are marine. They probably represent a grade (paraphyletic group) rather than a clade (monophyletic group).
Xenusia includes the following orders and families:
These taxa are only known from the Chengjiang (Cambrian Stage 2 Series 3).
Onychophora are distinguished by their terrestrial habit, their ventral mouth; their antennae, jaws and oral papillae; they seem to be most closely related to the Paronychophora. Their first fossils are Carboniferous (Helenodora), although they may have had a cryptic earlier history.
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