Systematic Parasitology 57: 97–109, 2004. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. 97 Redescription of Electrotaenia malopteruri (Fritsch, 1886) (Cestoda: Proteocephalidae), a parasite of Malapterurus electricus (Siluriformes: Malapteruridae) from Egypt Alain de Chambrier 1 , Tom´ as Scholz 2 & Mohammed Hasan Ibraheem 3 1 D´ epartement des Invert´ ebr´ es, Mus´ eum d’Histoire Naturelle, PO Box 6434, CH-1211 Geneva 6, Switzerland 2 Institute of Parasitology, Academy of Sciences of the Czech Republic, Branišovsk´ a 31, 370 05 ˇ Cesk´ e Budˇ ejovice, Czech Republic 3 Zoology Department, Faculty of Science, Minia University, El-Minia 61519, Egypt Accepted for publication 28th August, 2003 Abstract The proteocephalidean cestode Electrotaenia malopteruri (Fritsch, 1886) (Proteocephalidae: Gangesiinae), the type- and only species of Electrotaenia Nybelin, 1942 and specific to the electric catfish Malapterurus electricus Gmelin (Siluriformes: Malapteruridae), is redescribed on the basis of freshly collected material from the River Nile in Egypt. The validity of Electrotaenia is confirmed and some unique characters of this genus, observed in extensive material from different host specimens from Egypt, Sudan, Sierra Leone and Nigeria are first reported or described in detail. Such details include the internal morphology of a rostellum-like apical organ which is disc- shaped with a flat or slightly concave apex, the structure of the ovary which is follicular to reticulate, the structure of the cirrus-sac, the presence of a medio-dorsal band of muscle fibres, and the morphology of the vagina and eggs. Introduction Two proteocephalidean tapeworms, Electrotaenia malopteruri (Fritsch, 1886) (Proteocephalidae: Gangesi- inae) and Corallobothrium solidum Fritsch, 1886 (Proteocephalidae: Corallobothriinae), have been de- scribed from the electric catfish Malapterurus electri- cus from the River Nile in Egypt (Fritsch, 1886). Since the original description, E. malopteruri has been re- ported by several authors (La Rue, 1911, 1914; Wood- land, 1925; Janicki, 1928; Nybelin, 1942; Khalil, 1963, 1971, 1973; Okaeme & Sagua, 1985; Schmidt, 1986; Khalil & Polling, 1997; Ibraheem, 1998), some of them having provided fairly detailed morpholo- gical descriptions. Nevertheless, some characteristics, which may be important for studies on the phylo- geny and systematics of proteocephalidean tapeworms (see Rego et al., 1998; Hoberg et al., 2001), have not been described or there have been discrepancies between individual authors, e.g. in the morphology of the scolex, the distribution of vitelline follicles and the morphology of a genital atrium. Furthermore, nobody has figured eggs, frontal sections of the scolex or cross-sections of the proglottides. It also needs to be pointed out that the correct spelling for this unique species of Electrotaenia is E. malopteruri and not E. malapteruri, as frequently used in the literature. Recently, a total of 27 Electrotaenia malopteruri were found in the intestine of one of the two Malapter- urus electricus catfish which were purchased alive in a market at Luxor, southern Egypt, by the senior author. Both fishes also harboured another proteocephalidean tapeworm Corallobothrium solidum. E. malopteruri, the only species of the gangesiine genus Electrotaenia Nybelin, 1942, is redescribed in this paper on the basis of a taxonomic evaluation of freshly collected ma- terial and comparison with voucher specimens from different regions of Africa. Materials and methods The worms were fixed immediately after dissection with hot 4% neutral formaldehyde solution, stained