202 Three species of Magnibursatus Naidenova, 1969 (Digenea: Derogenidae) from Atlantic and Black Sea marine teleosts Aneta Kostadinova 1,2 , Anne Marie Power 2 , Mercedes Fernández 2 , Juan Antonio Balbuena 2 , Juan Antonio Raga 2 and David I. Gibson 3 1 Department of Biodiversity, Central Laboratory of General Ecology, Bulgarian Academy of Sciences, 2 Gagarin Street, 1113 Sofia, Bulgaria; 2 Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, P.O. Box 22 085, 46071 Valencia, Spain; 3 Department of Zoology, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK Key words: Digenea, Magnibursatus, key to species, marine fish Abstract. Three species of Magnibursatus Naidenova, 1969 are described from marine teleosts: M. skrjabini (Vlasenko, 1931), the type species of the genus, from the gobiid Zosterisessor ophiocephalus on the Bulgarian Black Sea coast; M. bartolii sp. n. from the sparid Boops boops off the Atlantic coast of Spain; and M. minutus sp. n. from the gobiid Neogobius eurycephalus on the Bulgarian Black Sea coast. M. bartolii differs from all other Magnibursatus species in its larger sinus-sac (length >250 µm, width >150 µm) and the more posterior location of testes. This species is also unusual in that it occurs in the branchial chamber and on the gills of its host. M. minutus is distinguished by the distinctly smaller dimensions of the body (length <1000 µm, width <200 µm), organs and eggs. These species are also distinguished from both M. caudofilamentosa (Reimer, 1971) and Tyrrhenia blennii Paggi et Orecchia, 1975. A key to the species of Magnibursatus is presented. During a survey of parasites of bogue, Boops boops (L.), off the Atlantic coasts of Spain, we came across a species possessing characteristics of two halipegine derogenid genera, Magnibursatus Naidenova, 1969 and Tyrrhenia Paggi et Orecchia, 1975. In attempting to identify the specimens we have examined comparative material (27 specimens) from Black Sea gobiid fishes provisionally identified as Magnibursatus skrjabini (Vlasenko, 1931) Naidenova, 1969 by Dr. G. Dimitrov (Bulgarian Academy of Sciences). We have found that the Atlantic form and part of the Black Sea material both show some distinctive features, which led us to describe them as new species. This paper includes a redescription of M. skrjabini and descriptions of two new species of Magnibursatus, one collected from B. boops off the Northern Atlantic coasts of Spain and the other from Black Sea gobiids. MATERIALS AND METHODS The trematodes from B. boops were dissected out from freshly frozen fish, fixed in alcohol-formol-acetic acid (AFA), transferred to 70% ethanol, stained with iron acetocarmine (Georgiev et al. 1986) and mounted in Canada balsam. Specimens from Black Sea fishes were dissected out from freshly caught fish, killed in a hot normal saline solution, transferred to 70% ethanol, stained and mounted as above. The type and voucher material is deposited at The Natural History Museum, London [BM(NH)] and in the collections of both the Central Laboratory of General Ecology, Bulgarian Academy of Sciences (CLGE) and the Cavanilles Institute of Bio- diversity and Evolutionary Biology, University of Valencia (ICBIBE). The following abbreviations for ratios (expressed as percentages) are used in the text and table: FO/BL, forebody length as a proportion of body length; PT/BL, post-testicular field length as a proportion of body length; AT/BL, distance from ventral sucker to anterior testis as a proportion of body length; and OV/BL, post-ovarian field length as a proportion of body length. Measurements and scales are in micrometres. RESULTS Family D e r o g e n i d a e Nicoll, 1910 Subfamily H a l i p e g i n a e Poche, 1926 MAGNIBURSATUS Naidenova, 1969 Magnibursatus skrjabini (Vlasenko, 1931) Fig. 1A, B, D Redescription. Based on 12 whole-mounts. Meas- urements (see Table 1) taken from 10 adults. Body elongate, widest at level of ventral sucker or testes. Tegument thick, unarmed. Pre-oral lobe present. Oral sucker subterminal, spherical. Ventral sucker muscular, distinctly larger than oral sucker, cup-shaped, slightly protuberant. Forebody relatively long. Prepharynx absent. Pharynx subglobular. Oesophagus short. Intesti- nal bifurcation just posterior to pharynx. ‘Drüsenmagen’ present. Caeca with thick epithelial lining, end blindly fairly close to posterior end of body. FOLIA PARASITOLOGICA 50: 202–210, 2003 Address for correspondence: J.A. Balbuena, Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, P.O. Box 22 085, 46071 Valencia, Spain. Phone: ++34 963 543 658; Fax: ++34 963 543 733; E-mail: j.a.balbuena@uv.es