Photosensitivity in sponge due to cytochrome c oxidase?

An action spectrum for photosensitivity in sponge larvae
published by Leys et al. [J. Comp. Physiol., A, 2002, 188,
199–202] was interpreted by the authors as being due to a
combination of light absorption by flavin or carotenoid in
the blue region, and another pigment such as pterin in the
long-wavelength region. Here we show here that their action
spectrum closely matches the absorption spectrum of reduced
cytochrome c oxidase that is present in sponges, and compare
with other photoreactions which are thought to be due to this
chromoprotein.