part of develops into late extended germ band embryo copper cell primordium midgut interstitial cell primordium embryonic/larval midgut primordium posterior fused midgut primordium embryonic primordium of adult posterior midgut posterior endoderm derivative posterior midgut primordium P1 antEndoP posterior midgut proper primordium postMGP2 fly_anatomy.ontology The primordium that will develop into the posterior midgut of both larva and adult. This forms from the endodermal component of the amnioproctodeal invagination when it undergoes an epithelial-to-mesenchymal transition during stage 10 and so becomes distinct from the hindgut primordium with which it was previously contiguous. This primordium forms two lobes that extend laterally on either side of the yolk. During early stage 11, the interstitial cell precursors delaminate from the tip of the primordium. During stage 11/12 the precursors of the adult posterior midgut become distinct and the remaining primordium undergoes a mesenchymal to epithelial transition after which (during stage 12) fusion of anterior and posterior midgut primordia begins, forming the fused midgut primordium. midgut posterior body posterior midgut inclusive primordium FBbt:00005251 FBbt:10005329 This primordium may be temporally subdivided into the inclusive posterior midgut primordium, including adult midgut progenitors and the posterior midgut primordium proper, that contains only progenitors of the embryonic/larval midgut. However, the proper primordium exists only briefly during stage 12 and so we have chosen not to represent it in this ontology. Please use 'posterior midgut primordium' for both cases. FBbt:00000448