Dermal modifications of the red lionfish, Pterois volitans.

Vertebrates have evolved flexible and hard dermal armor, but there is often a tradeoff between mobility and protection. Skeletal modifications include fish scales, the shells of tortoises and turtles, and the cranial projections that are found in marine iguanas and lionfish. Sexual dimorphisms of cranial structures are prominent in fishes; we hypothesized that cranial projections of Pterois volitans will change over ontogeny and are sexually dimorphic.