Muscles 5 and 8 are not identifiable in hemizygous embryos. Instead, small syncytia with variable shapes are located near the normal ventral attachment sites of these two muscles. Fibres resembling muscle 25 are present in the embryos, but they are highly variable in shape and often connect to incorrect attachment sites. The alary muscles are completely missing.
The number of lateral adult muscle precursor cells (lAMPs) is strongly reduced in mutant embryos: no lAMPs are detectable in approximately 50% of hemisegments, while in the remaining hemisegments, only one instead of two lAMP cells are seen.