(ABOVE: Dorsal rows in skin of a small-spotted catshark hatchling (Scyliorhinus canicula)

RORY COOPER

Patterns in young catshark skin are similar to those in chick feathers, according to a study published yesterday (November 7). The finding suggests Alan Turing’s reaction-diffusion model, which explains the autonomous development of spatial patterns, applies not only to spines, scales, and teeth in four-legged animals and to feathers in birds, as scientists thought, but also to shark and skate skin. Such patterns in the fish’s skin may have allowed it to develop protective armor or reduce drag in the water.

SEM image of scales on a catshark hatchling's flank RORY COOPER

R.L. Cooper et al. “An ancient Turing-like patterning mechanism regulates skin denticle development in sharks,” Science Advances, 4:eaau5484, 2018.