Xenusiid
Xenusiids (class Xenusia) are a group of lobopods resembling Xenusion.[1] They have relatively large, annulated, cylindrical body. Their lobopod legs have tubercles at their bases. Some have large frontal appendages,[1] although these may represent taphonomic artefacts.[2] Their mouth is terminal or subterminal, and they are marine.[3] They probably represent a grade (paraphyletic group) rather than a clade (monophyletic group).
Xenusia includes the following orders and families:[3]
- Archonychophora Hou & Bergstrom, 1995
- 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
References
- ^ a b Jianni Liu Degan Shu, Jian Han, Zhifei Zhang & Xingliang Zhang (2006). "A large xenusiid lobopod with complex appendages from the Lower Cambrian Chengjiang Lagerstätte" (PDF). Acta Palaeontologica Polonica 51 (2): 215–222. http://www.app.pan.pl/archive/published/app51/app51-215.pdf.
- ^ Julián Monge-Nájera & Xianguang Hou (2002). "Experimental taphonomy of velvet worms (Onychophora) and implications for the Cambrian "explosion, disparity and decimation" model" (PDF). Revista de Biología Tropical 50 (3-4): 1133–1138. PMID 12947596. http://www.ots.ac.cr/tropiweb/attachments/volumes/vol50-3-4/26-MONGE.pdf.
- ^ a b George Poinar, Jr. (2000). "Fossil onychophorans from Dominican and Baltic amber: Tertiapatus dominicanus n.g., n.sp. (Tertiapatidae n.fam.) and Succinipatopsis balticus n.g., n.sp. (Succinipatopsidae n.fam.) with a proposed classification of the subphylum Onychophora". Invertebrate Biology 119 (1): 104–109. doi:10.1111/j.1744-7410.2000.tb00178.x. JSTOR 3227105.
- ^ Xian-Guang Gou, Xiao-Ya Ma, Jie Zhao & Jan Bergström (2004). "The lobopodian Paucipodia inermis from the Lower Cambrian Chengjiang fauna, Yunnan, China". Lethaia 37 (3): 235–244. doi:10.1080/00241160410006555.