Visual systems, behaviour, and environment in cephalopods

Abstract

The vision of cephalopods is interesting for many reasons. One is the existence of the primitive cephalopod Nautilus, which has apparently changed little over the past 150 million years or so. The modern coleoid cephalopods are probably derived from ancestors that resembled Nautilus quite closely (Naeff, 1923), and its eye is among its many apparently primitive features, giving an indication of how the visual system of modern cephalopods developed. A second reason is that the eyes of cephalopods provide a striking example of convergent evolution with those of fishes. Cephalopods face similar visual problems to fishes, and superficially the eyes of the two groups are remarkably similar. However, their development and detailed structure are quite different, and fishes and cephalopods have no common ancestors which had camera eyes: they have achieved similar solutions to many problems, but by very different routes.