Nudibranch color diversity shares a common physical basis in guanine photonic structure ‘pixels’ - Samuel Humphrey; Xianglian He; Tobias Priemel; Vera Marie Titze; Sinuhé Perea-Puente; Vivek Subramanian; Cedric Bouchet-Marquis; Bruno Jesus; Silvia Vignolini (Proceedings of the National Academy of Sciences, 2026)