The pupil response of a teleost fish, Porichthys notatus: description and comparison to other species

The pupil response of Porichthys notatus to different intensities of illumination is described and compared to that of P. myriaster, Cephaloscyllium ventriosum, and a human. While the fully dark adapted pupil is round, at the highest light intensities it consists of only two small, almost independent, apertures with a total area 4.9% of that observed in the fully dilated animal. The response is at least partially consensual and occurs, albeit at a much reduced rate, in isolated eyes. P. notatus also displays retinomotor movements comparable to those seen in most teleosts, suggesting that, contrary to most previous assumptions, pupillary responses and retinomotor migrations are not mutually exclusive. (C) 1998 Elsevier Science Ltd. All rights reserved.