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Proarticulata

Proarticulata is a phylum of extinct, near-bilaterally symmetrical animals known from fossils found mainly in the Ediacaran (Vendian) marine deposits, with some few possible related specimen found through Cambrian until late Devonian, and dates to approximately 567 to 550 million years ago. The name comes from the Greek προ = "before" and Articulata, i.e. prior to animals with true segmentation such as annelids and arthropods. This phylum was established by Mikhail A. Fedonkin in 1985 for such animals as Dickinsonia, Vendia, Cephalonega, Praecambridium and currently many other Proarticulata are described.

Morphology
Vendiamorpha The body is completely segmented, with all isomers curved towards the posterior, and the first isomer is normally much larger than the rest. The first two isomers at the anterior dorsal end are partly fused. (e.g., Vendia, Paravendia and Karakhtia). Cephalozoa These proarticulatans are incompletely segmented, as the anterior zone is free of isomers, often making a "hairband" like appearance (example cephalozoans include Yorgia, Praecambridium, Andiva, Archaeaspinus, Ivovicia, Podolimirus, Tamga, Spriggina, Marywadea and Cyanorus). Some cephalozoans from the family Yorgiidae demonstrate pronounced asymmetry of the left and right parts of the body. For instance, Yorgia initial right isomer is the only one which spreads far towards the left side of the body. Archaeaspinus has an unpaired anterior lobe confined by the furrow to the left side only. '' feeding on surface algae. In Cephalonega stepanovi and Tamga hamulifera the zone containing the isomers is encircled by a peripheral, undivided zone. == List of proarticulates ==
List of proarticulates
Body fossils Armillifera Fedonkin, 1980 :A. parva Fedonkin, 1980 • Andiva Fedonkin, 2002 :A. ivantsovi Fedonkin, 2002 • Archaeaspinus Ivantsov, 2007 :C. stepanovi (Fedonkin, 1976)) :D. tenuis Glaessner & Wade, 1966 • Ivovicia Ivantsov, 2007 • Yorgia Ivantsov, 1999 :E. axiferus Ivantsov, 2002. :E. waggoneris Ivantsov, 2011. This is a trace of Yorgia waggoneri :E. costatus Ivantsov, 2011. This is a trace of Dickinsonia costataPhyllozoon Jenkins & Gehling, 1978 :P. hanseni Jenkins & Gehling, 1978 == See also ==
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