Two new species of Ergasilidae are described from southern Africa; a representative of the genus Dermoergasilus Ho et Do, 1982 on the gill rackers and one of Ergasilus von Nordmann, 1932 on the gill filaments of the striped mullet, Mugil cephalus L.The striped mullet, Mugil cephalus Linnaeus, has a wide geographical distribution and is parasitized by more than 40 different species of parasitic copepods (Ho & Do, 1982). It acts as host for seven species of Ergasilidae, i.e. Diergasilus kasahari Do, 1981, Dermoergasilus amplectens (Dogiel et Akhmerov, 1952, Ergasilus seiboldi von Nordmann, 1832, Nipergasilus bora (Yamaguti, 1939) and Ergasilus lizae Kroyer, 1963, Ergasilus mugilis Vogt, 1879 and Ergasilus cyanopictus Carvalho, 1962. Ergasilids have been reported from mullets on the African continent, i.e. E. lizae from Thnisia (Raibaut, Ben-Hassine & Prunes, 1975) and Ghana (Paperna, 1969). The present study has shown that two new species of Ergasilidae occur on the southern periphery of the continent, which are described below.Type specimens were deposited in the collection of the Dept. of Zoology, Rand Afrikaans University.Dermoergasilus mugilis sp. nov.-Holotype: E 1986/5/15-1, preserved specimen.-Type locality: Mouth of Keurbooms River, Cape Province, South Africa. -Type host: Mugil cephalus L.-Paratypes: E 1986/5/15-2 and E 1986/5/15-3, preserved specimens from the type locality and the Bushmans River mouth, Transkei. -Material studied: Six ovigerous females from the type locality.
DescriptionFemale: Total length 1045 m. Cephalothorax large and about half the total length. Antennal region set off from the rest of the cephalothorax (Fig. la). A broad dorsal plate occurs across the posterior part of the cephalothorax (Fig. la). The anterior region carries the first and second antennae. Thoracic segments progressively decrease in width caudally. Fourth free thoracic segment much reduced and pedigerous. Genital segment longer than wide and indented ventrolaterally (Fig. lb), with two elongated egg sacs (when present) originating from dorsolateral slits (Fig. ld). Abdomen consists of three segments, first longer than second, but second narrower (Fig. lb). Third segment split dorsoventrally to accomodate the anal slit. Caudal ramus slightly broader than long, bearing a ventral digitiform process, two shorter setae and a medial, long seta (Fig. lb).