part_of part of part of develops_from develops from develops from has potential to develop into has potential to develop into immediate transformation of somite presomitic mesoderm EMAPA:16189 AAO:0011086 TAO:0000279 unsegmented mesenchyme Unsegmented field of paraxial mesoderm present posterior to the most recently formed somite pair, from which somites will form. Kimmel et al, 1995.[TAO] segmental plate UBERON:0003059 uberon presumptive somite mesoderm Unsegmented field of paraxial mesoderm present posterior to the most recently formed somite pair, from which somites will form. It is reasonable to assume that the proximate invertebrate ancestor of the vertebrates had an amphioxus-like tail bud in its larval stage. This archetypal tail bud would have (...) (3) lacked any component of mesenchyme cells, (4) budded off new mesodermal segments directly, without any intervening zone of presomitic mesoderm (...). Then, early in vertebrate evolution, epithelium-to-mesenchyme interconversions (and the gene networks for effecting them) became prominent features of development. (...) In any case, conspicuous mesenchymal components tended to be added to the vertebrate tail bud itself. In addition, a mesenchymatous presomitic mesoderm (not a part of the tail bud proper) came to intervene between the tail bud and the forming somites.[well established][VHOG] EFO:0001982 XAO:0000057 EMAPA:16752 unsegmented paraxial mesoderm VHOG:0000559 PSM ZFA:0000279 somitomeric mesoderm somitogenic mesoderm paraxial mesoderm developing anatomical structure presumptive structure presumptive segmental plate