A new species of Acusicola Cressey (Copepoda: Ergasilidae) from northeastern Brazil.

A new species of Acusicola is described based on adults of both sexes taken from plankton samples collected in the upper reaches of the Piauí River estuary, in the northeast of Brazil. Ovigerous females were present in the plankton. The new species, Acusicola minuta n. sp., can be distinguished from its congeners by its small body size, female antennal morphology and leg setation. The male described here as A. minuta n. sp. is the first known male attributed to the genus.

Ergasilid copepods (Poecilostomatoida) from the gills of primitive Mugilidae (grey mullets)

All representatives of the subfamily Agonostominae of grey mullets in the collections of The Natural History Museum in London were examined for parasitic copepods. Agonostomus monticola, Joturus pichardi, Aldrichetta forsteri and Cestraeus goldiei. Three new species of Acusicola and two new species of Ergasilus were found: E. parabahiensis n. sp. on A. monticola from Guyana and E. acusicestraeus n. sp. on C. goldiei from Papua New Guinea. Acusicola spinuloderma n. sp. was found on A. monticola and J. pichardi collected from different localities in Central America, A. mazatlanesis n. sp. on the same host from West Mexico (Mazatlan) and A. joturicola n. sp. on J. pichardi from Panama. Descriptions of E. australiensis Roubal, from Aldrichetta forsteri, are presented. The host-parasite relationships and geographical distributions of hosts and their parasitic copepods are analyzed. (AU)