MOESM1 of Developing an ancient epithelial appendage: FGF signalling regulates early tail denticle formation in sharks CooperRory MartinKyle RaschLiam FraserGareth 2017 Additional file 1. Caudal denticle abortion from preliminary SU5402 treatment trial. A preliminary drug trial involved treating S. canicula embryos with a single injection resulting in a 50 ¾M concentration of SU5402 in the egg case, which then remained sealed for 30 days. The egg case then opened, and the embryo was allowed an additional 30-day recovery period before fixation. The sample was then stained with alcian blue and alizarin red. There is a clear vestige (B, black arrowhead), indicating a single denticle from the sequence was aborted, as a result of this SU5402 treatment.