Homozygous embryos show a normal anterior cellularisation domain of larger yolk stalk diameters, but there is little difference in the yolk stalk diameters between the pre-cephalic furrow domain and the posterior domain during cellularisation (in contrast to wild type). The cephalic furrow does not form at the onset of gastrulation in mutant embryos and the initiator cells do not undergo their characteristic shape change. However, by mid-germband extension the embryos have formed a regular, cephalic furrow-like invagination.

The denticle bands of segments T1, T3, A2, A4 and A6, and the naked cuticle of segments T2, A1, A3, A5 and A7 are deleted in prd^unspecified mutant embryos. No head fold is visible during gastrulation.