Xenusiids are a group of lobopods resembling Xenusion

Xenusion

Xenusion is a possible very primitive arthropod/onychophore known from two specimens found in glacial debris in Germany. They probably originated in the Kalmarsund Sandstone of Southern Sweden and are probably late Neoproterozoic. The specimens are not especially well preserved...

. They have relatively large, annulated, cylindrical body. 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

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 and families

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

:

• Archonychophora Hou & Bergstrom, 1995
  • Luolishaniidae Hou & Bergstrom, 1995
  • Paucipodiidae Hou et al., 2004
• Protonychophora Hutchinson, 1930
  • Aysheaiidae Walcott, 1911
  • Xenusiidae Dzik & Krumbiegel, 1989
• Scleronychophora Hou & Bergstrom, 1995
  • Eoconchariidae Hou & Shu, 1987
  • Hallucigeniidae Conway Morris, 1977
  • Cardiodictyidae Hou & Bergstrom, 1995
• Paronychophora Hou & Bergstrom, 1995
  • Onychodictyidae Hou & Bergstrom, 1995