Trilobozoa

Trilobozoa ("three-lobed animals") is a taxon of extinct organisms which displayed tri-radial symmetry. Fossils of trilobozoans are restricted to marine strata of the Late Ediacaran period — prior to the Cambrian explosion of more modern life forms.

Trilobozoa Temporal range: Late Ediacaran, around 565–548 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Subkingdom:	Eumetazoa
Phylum:	†Trilobozoa Fedonkin, 1985 [nom. transl. Runnegar, 1992 ex Class Trilobozoa Fedonkin, 1985]
Families and Genera
See text

The taxonomic affinities of this groups are open to debate. Ivantsov and Fedonkin (2002) place them among the cnidarians. They reasoned that since the conulate Vendoconularia exhibited six-fold symmetry, the conularids — then regarded as a sister group to the scyphozoan cnidarians — must be nested within the trilobozoa, making the trilobozoan group part of the cnidarian phylum.

Most trilobozoans were disk-shaped, typified by Tribrachidium. Through comparisons with the other discoidal trilobozoans, it appears the different "arm" patterns on each genus/species occurred due to growth arresting or progressing at different stages of development.

Classification

• Phylum Trilobozoa †
  • Family Albumaresidae †
    • Genus Albumares †
    • Genus Anafesta †
    • Genus Skinnera †
  • Family Tribrachididae †
    • Genus Tribrachidium †
  • Family Anabaritidae †
    • Genus Aculeochrea †
    • Genus Anabarites †
    • Genus Cambrotubulus †
    • Genus Mariochrea †
    • Genus Selindeochrea †
  • Family incertae saedis
    • Genus Gastreochrea †
    • Genus Hallidaya †
    • Genus Kotuites †
    • Genus Lobiochrea †
    • Genus Longiocrea †
    • Genus Paragloborilus †
    • Genus Rugoconites †
    • Genus Tinsitheca †
    • Genus Triforillonia†

See also

• List of Ediacaran genera

References

• Ivantsov, Andrei Yu.; Fedonkin, Mikhail A. (2002). "Conulariid-like fossil from the Vendian of Russia: A metazoan clade across the Proterozoic/Palaeozoic boundary". Palaeontology. 45 (6): 1219–1229. doi:10.1111/1475-4983.00283.
• Fedonkin, Mikhail A. (2007). The Rise of Animals: Evolution and Diversification of the Kingdom Animalia. JHU Press. ISBN 9780801886799.
• McMenamin, M.A.S (1998). The Garden of Ediacara. New York: Columbia University Press. ISBN 0-231-10559-2.
• Dzik, Jerzy (2003). "Anatomical Information Content in the Ediacaran Fossils and Their Possible Zoological Affinities". Integrative and Comparative Biology. 43 (1): 114–126. doi:10.1093/icb/43.1.114. PMID 21680416.

External links

• Ediacara Assemblage University of Bristol