Biogeography and phylogeny of Paraergasilus Markevich, 1937 (Copepoda: Ergasilidae) with descriptions of two new species from the gills of grey mullet

Two new species of Paraergasilus are reported from the gills of four species of grey mullet (Mugilidae). Paraergasilus dichotomus n. sp. was recorded on M. cephalus Linn. from New South Wales, Australia. Paraergasilus curtus n. sp. was found on the same host in Western Australia, on Valamugil cunnesius (Valenciennes) from the Philippines, on Valamugil seheli (Forsskal) from Sri Lanka and on Liza macrolepis (Smith) from Socotra, Yemen. Both new species differ from congeners in possessing a bifid antennary claw. The distribution of Paraergasilus species is summarized and the host specificity of Paraergasilus species is examined. Phylogenetic analysis of the relationships between Paraergasilus species indicated that there are two main lineages within the genus.