New records of rare derogenids (Digenea: Hemiuroidea) from Mediterranean sparids, including the description of a new species of Magnibursatus Naidenova, 1969 and redescription of Derogenes adriaticus Nikolaeva, 1966 Aneta Kostadinova Æ David I. Gibson Received: 23 March 2009 / Accepted: 29 May 2009 Ó Springer Science+Business Media B.V. 2009 Abstract Records of derogenid digeneans in the Mediterranean and Black Sea region are scarce and tend to be restricted to a small number of host-groups, but especially to sparid fishes. This work reports on the presence of derogenine and halipegine derogenids from two sparids, Diplodus annularis (L.) and D. sargus (L.), from off the Mediterranean coast of Spain. Five derogenid forms were recovered. Derog- enes adriaticus Nikolaeva, 1966 is redescribed from Diplodus annularis, and Derogenes sp. is described from the same host but differentiated from the former species. Magnibursatus barretti n. sp. is described from Diplodus sargus and distinguished from other species of the genus especially by its smaller body size and smaller eggs. M. bartolii Kostadinova, Power, Ferna ´ndez, Balbuena, Raga & Gibson, 2003 is redescribed from D. sargus, a new host for this species. A single specimen from D. sargus, somewhat similar to M. minutus Kostadinova, Power, Ferna ´ndez, Balbuena, Raga & Gibson, 2003, is also described, as it exhibits some morphometric differences from the latter species. Introduction Derogenid hemiuroid digeneans have only occasion- ally been recorded in sparids (Pisces: Sparidae) and then predominantly in the Mediterranean region. Halipegine derogenids were associated with the ancient Tethys Sea of Tertiary times by Gibson & Køie (1991), thus explaining their presence in the fishes of the Mediterranean and neighbouring waters. How- ever, until recently, Mediterranean and Black Sea records of derogenids were few, being mainly limited to a small number of apparently monotypic genera. Nevertheless, although the number of published records has remained low, recent work has indicated that the species involved may not be just relictual forms (cf. Gibson & Bray, 1979; Gibson & Køie, 1991), but, at least in the case of one genus, Magnibursatus Naidenova, 1969, the number of species is greater than previously believed, indicating some recent radiation. The type- and only species of the halipegine genus Arnola Strandt, 1942, A. microcirrus (Vlasenko, 1931), originally described on the basis of material from Diplodus annularis (L.) in the Black Sea, appears to be the most recorded species with the widest range of sparid hosts: Boops boops (L.) A. Kostadinova (&) Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branis ˇovska ´ 31, 370 05 C ˇ eske ´ Bude ˇjovice, Czech Republic e-mail: Aneta.Kostadinova@uv.es A. Kostadinova Department of Biodiversity, Central Laboratory of General Ecology, Bulgarian Academy of Sciences, 2 Gagarin Street, 1113 Sofia, Bulgaria D. I. Gibson Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK 123 Syst Parasitol (2009) 74:187–198 DOI 10.1007/s11230-009-9214-6