First report on the occurrence of an actinosporean stage (Myxozoa) in oligochaetes from Spanish freshwaters

Oligochaetes living in the Mijares River close to the Sitjar reservoir, and polychaetes from the brackish and marine waters of a channel flowing into the Mediterranean Sea, both in the province of Castellon (Spain), were exam ined for the presence of actinosporea. An aurantiactinomyxon was isolated f rom 60 specimens of the oligochaete Branchiura sowerbyi collected from the river, but no actinospores were isolated from 160 polychaetes collected fro m the sea channel. The aurantiactinospores were detected by the cell-well p late method. The detected species are not identical with any of the auranti actinomyxon forms hitherto described in the literature. This is the first r eport on the occurrence of an actinosporea in Spanish waters.