A SINGLE MICROPYLE IN THE EGGS OF THE MOST BASAL LIVING ACTINOPTERYGIAN FISH, POLYPTERUS (ACTINOPTERYGII, POLYPTERIFORMES)

Breeding of Polyterus, the most basal living actinopterygian, provided the opportunity to study the surface structure of its eggs with SEM f or the first time. The investigation; revealed the previously overlook ed presence of a micropyle at the animal egg pole, thus rejecting rece nt textbook belief that the eggs of Polypterus lack a micropyle. Compa rison with data for other gnathostomes demonstrates that eggs with a m icropyle are a further synapomorphy for Actinopterygii and confirm mem bership of the Cladistia in that group.