Sloppy paired 1 and Sloppy paired 2 appear to combine the functions of gap, pair rule and segment polarity classes of segmentation proteins.
Crocodile has a dual role in Drosophila morphogenesis.
An early role is in establishing the domains of expression for wingless and engrailed in the clypeolabrum , the anterior most segment of the fly's head. The role of croc early expression can be observed by examining internal clypeolabral structures. Two dorsal rows of muscle attachment sites, known as apodemes, are present in croc mutant embryos, while the single ventral row of apodemes is missing. In addition, the palisade-like structure of the dorsopharyngeal muscles never forms. Subsequent to its early role in determining muscle attachment sites, crocodile plays a role in the structuring of the intercalary segment.