Isomer (Proarticulata)

Yorgia waggoneri demonstrate obvious asymmetry of left and right parts of the body
The Dickinsonia costata is subradial divided by isomers entirely, the anterior part (head) of the body on the right-bottom

Isomer (Greek isos = "equal", méros = "part") is an element of transverse body articulation of the bilateral fossil animals of the Phylum Proarticulata from the Ediacaran (Vendian) period. This term has been proposed by Andrey Yu. Ivantsov, a Russian paleontologist from the Laboratory of the Precambrian organisms, Paleontological Institute, Russian Academy of Sciences.[1]

  1. ^ Ivantsov, A.Y. (2001). "Vendia and Other Precambrian "Arthropods"". Paleontological Journal. 35 (4): 335–343.