Dr. Murai Éva szerk.: Parasitologia Hungarica 23. (Budapest, 1990)
Remarks: F. anatis is considered to be one of the most frequent and wide-spread acanthocephalans of waterfowl in the Palaearctic (KHOKHLOVA 1986). It was reported in Hungary by EDELÉNYI (1964) and MURAI et al. (1983, 1985) from several aquatic bird species. The comparison of morphological data of specimens studied from different hosts (Table 4) shows a considerable variability of the male proboscis and hook measurements. There are only two descriptions of this species in the available litera-ture: that of LUEHE (1911) which has been completed by PETROCHENKO (1958) and that of ATRASHKEVICH (1982) which is the only one based on specimens from concrete host and region (Anas acuta in Chukotka). The former description is also presented by KHOKHLOVA (1986). Only the hook dimensions of our specimens fromA platyrhynchos correspond to the measurements given by ATRASHKEVICH (1982) for F. anatis (blade length of the first 7 hooks is up to 0.041). The specimens from B. clangula and F. atra have larger hooks (see Table 4) and they are more similar in this feature to F. trophimenkoi Atrashkevich, 1982 (blade length up to 0.048). Another substantial difference among the male specimens studied concerns the shape of the proboscis. The worms from A platyrhynchos have oviform proboscides while those from B. clangula and F. atra have anteriorly rounded proboscides with a form which is rather oval than oviform. The proboscis dimensions of the specimens from B. clangula and F. atra are considerably larger than both those from A. platyrhynchos in the present study and those in the published descriptions (according to PETROCHENKO (1958) proboscis is 0.36-0.40 long and according to ATRASHKEVICH (1982) it is 0.329-0.379). In specimens of F. anatis from F. atra from Bulgarian Black Sea Coast (with proboscis length 0.347-0.410) (DIMITROVA and GENOV, in press) was observed similar but not so clear exceeding the known limits of variability in proboscis dimensions. The taxonomic value of differences found is quite unclear. Although F. anatis is considered a common parasite of waterfowl, its variability is insufficiently known. It is possible that the differences result from individual or host-dependent variability. It may well be that two or more similar species are reported as F. anatis. The first steps in the direction of solving these problems are the investigations of RUDMINAYTIS and KONTRIMAVICHUS (1981) and ATRASHKEVICH (1982). Polymorphus (P.) diploinflatus (Lundstrom, 1942) Specimens studied: No. 2118, 5 females from small intestines of Anas platyrhynchos , Hortobágy, January 1971. Description (Tables 5, 6, Fig. 4): Female: Total length 4.78-6.57. Trunk fusiform with characteristic constriction dividing anterior and middle part; latter part widest; 4.08-5.13 long and with maximum width 1.04-1.59. Posterior part greatly narrowed, 0.61-0.72 wide. Anterior part (with length 0.88-1.02) of trunk covered with spines, spines situated in 50-60 longitudinal rows of 20-27 each; length of spines 0.020-0.025. Proboscis elongate, oval, 0.563-0.613 long and with maximum width 0.263-0.306 at the level of 3rd-4th spines.
