In Src42A^F80 mutant embryos the dorsal trunk is 34% shorter and the transverse connectives are 54% shorter than in wild type. Overall embryo length is unchanged. Dorsal trunk luminal diameter is 15% larger than in controls. The unicellular dorsal and ganglionic branches are normal in length.

The apical surfaces of Src42A^F80 mutant dorsal trunk cells are on average 22% smaller than in controls. Furthermore, the shapes and orientations of cell surfaces are strikingly altered, with cell surfaces elongated circumferentially. Time lapse imaging shows that the apical surfaces of Src42A^F80 mutant dorsal trunk cells only expand circumferentially, rather than both axially and circumferentially as is seen in wild type. In wild type apical junctions remain straight, but in Src42A^F80 mutants the axially oriented junctions become increasingly corrugated. The sporadic conversions of circumferential junctions into apical junctions seen in wild type embryos is not observed in Src42A^F80. The regular circumferential arrangement of taenidial rings is not affected in Src42A^F80 mutants.

Src42A^F80 mutants show abnormal epithelial organisation. From stage 14, the cells on the dorsal side of the posterior dorsal trunk metameres are elongated perpendicular to the tube axis. The nuclei appear to stack on one another, resembling a pseudo stratified epithelium. However most of the cells reach both the luminal and basal surfaces, indicating that the epithelium is not multilayered. The longest axis of dorsal trunk cells is on average 23% longer in Src42A^F80 mutants compared to controls.