The genes investigated exhibit spatially collinear expression within the trunk (Fig. 6 and Table 2) and their global expression patterns are comparable to snakes; The expression of HoxC13 also corresponds to the transition into the caudal region and the expression domains of HoxC5, HoxA6, HoxC6, HoxB8, HoxC8 and HoxC10 are not directly linked to morphology in the axial skeleton in the dorsal region.
The expression of HoxC10 is observed within the 60 posterior most ribbearing somites and thus, as in snakes, conflicts with its known role as a rib suppressor gene.
In contrast to snakes however, no gradual anterior limits of expression are observed for any of the genes examined and none of the genes' expression domains seems to correspond directly to the transition from rib-less to rib-bearing somites.