immediate transformation of germ layer mesoderm AAO:0000304 BILA:0000037 BTO:0000839 CALOHA:TS-0623 EFO:0001981 EHDAA2:0001128 EHDAA:124 EHDAA:160 EHDAA:168 EHDAA:183 EMAPA:16083 EV:0100006 FBbt:00000126 FMA:69072 GAID:522 MAT:0000174 MESH:A16.254.425.660 MIAA:0000174 Primary germ layer that is the middle of the embryonic germ layers.[AAO] TAO:0000041 The Bilateria are triploblastic (with true endoderm, mesoderm, and ectoderm) (...).[well established][VHOG] The middle germ layer of the embryo, between the endoderm and ectoderm. UBERON:0000926 UBERON:0003263 UMLS:C0025485 VHOG:0000152 XAO:0000050 ZFA:0000041 embryonic mesoderm entire mesoderm mesodermal mesodermal mantle sponges do not seem to have a mesoderm and accordingly Amphimedon lacks transcription factors involved in mesoderm development (Fkh, Gsc, Twist, Snail)[http://www.nature.com/nature/journal/v466/n7307/full/nature09201.html]. Mesoderm may not be homologous across verteberates uberon presumptive mesoderm