223 Systematic Parasitology 28 : 223- 228 , 1994 . . . . © 1994 Kluwer Academic Publish er s. Pnnied in th e Neth e1/c111ds. Hadwenius tursionis (Marchi, 1873) n. comb. (Digenea, Cai:npulidae) from the bottlenose dolphin Tursiops truncatus (Montagu, 1821) in the western Mediterranean Mercedes Fernandez, Juan A. Balbuena and J. Antonio Raga . . Department of Animal Biology , Uni versity of Valencia , Dr Moliner 50, 46100- Bur1asot, Valencta , ... Spain Acct:pted for publication 17th March, 1993 Abstract The taxonomic position of· Synthesium tursionis (Marchi, 1873) (Digenca, Campulidae) is revised , on material from 147 worms from four bottlenose dolphins Tursiops truncatus stranded off the Comumdad Valenciana (Spanish western Mediterranean). The species is transferred to Hadwenius , as H . tursionis n. comb., and characterised by a high length/width ratio of the body, spinose cirrus and unarmed metraterm. Synthesium , a monotypic genus, be .comes a synonym of Hadwenius. The intraspecific variation of some morphological traits is briefly discussed. Introduction ln 1873, Marchi reported a new trematode spe- cies , Distomum tursinnis , from the intestine of a bottlenosed dolphin Tursiops truncatus (Montagu, 1821), but the description was rather incomplete and accompanied by a poor illustration. Some years later, Poirier (1886) described from the same host D. longissimum , which was syn- onymised with D. tursinnis by Parona (1896). Odhner (1926) suggested that n. tursionis should be transferred tentatively to the genus Ortho- splanchnus Odhner , 1905, within the family Cam- pulidae Odhner, 1926. However, Stunkard & Alvey (1930) maintained that this would vio late the morphological unity of Orthosplanchnus (al- though they did not explain why) and proposed the erection of a new campulid genus, Synthesium, for this species. Pripc (1932) agreed with this a<.: - tion because "the inclusion of the species in Or- thosplanr:hnus , or in any related genera, would necessitate extensive revision of the diagnosis of these groups ", which he found " inadvisable until more species have been described ". At that time, most redescriptions of Synthesium tursionis were based on Poirier's (1886) work, being the illustration of a specimen la<.:king an- terior caecal diverticula (see Poirier, 1886, plate I, fig . 6, reproduced in subsequent revisions, e.g. Price , 1932 ; Delyamure, 1955; Dawes, 1968). Ya- maguti (1958) modified the taxonomy of th e Cam- pulidae, establishing various subfami li es . The ap- parent absence of caecal diverticula in S. tursionis Led him to consider that it should be included in a separate subfamily, the Synthesiinae Yamaguti, 1958 . Ho wever, Delyamure & Serdyukov (1966) (see also Skrjabin, 1976) pointed out that S. tur- sionis did indeed have an intestine with anterior diverticula. Consequently, Skrjabin (1976) indi- cated that the validity of the subfamily Synthesii- nae could not be maintained, and tentatively transferred the species to the subfamily Orthos- planchninae Yamaguti, 1958. Nevertheless, the designation S. tursionis was retained and has been