| Abstract: | Polyclithrum ponticum sp. n. is described and P. mugilini Rogers, 1967 is redescribed. Both monogenean species are parasites of Mugil cephalus in the Black Sea. The new species differs from P. mugilini, P. alberti and P. boegeri by the lesser size of anchors, while it is distinguished from P. corallense by the larger size of these structures. P. ponticum sp. n. differs from all formerly described species by the greater length of dorsal connective bar. In both species from the Black Sea, "ear-like" structures situated near the external roots of anchors are described for the first time. It is suggested, that these structures take part in longitudinal, two-lobe folding of the haptor. The process of opening the haptor is probably performed by the additional bars of the haptor (bars 2 and 3 after: Rogers, 1967), joined to each other and with the anchors. The fifth pair of additional bars (Ernst e. a., 2000) derives from the "beard" of ventral connective bar and is united with its basal part. The sixth pair of additional bars (Ernst e. a., 2000) is considered as a typical "ribs" of the haptor, and therefore the "ribs" are represented by three pairs. Differences between marginal hooks of P. ponticum sp. n. and P. mugilini are insignificant, that probably depends on the presence of "ribs" of the haptor. Based on the subdivision of marginal hooks into two groups, the presence of additional supporting structure in the haptor, and the presence of the seminal receptacle, it is suggested that the subfamily Polyclithrinae Rogers, 1967 should include the genera Polyclithrum Rogers, 1967, Swingleus Rogers, 1969, Macrogyrodactylus Mamlberg, 1959, and probably Fundulotrema Hargis, 1955. Based on such characters as the lack of the anchors, the presence of suckers in the haptor, and ovipositing of eggs, it seems to be expedient to use the following taxa in systematics of gyrodactylids: Isancistrinae Fuhrmann, 1928 (genera Isancistrum, Anacanthocotyle); Gyrdicotylinae Vercammen-Grandjean, 1960 (Gyrdicotyle) and Ooegyrodactylinae Harris, 1983 (genera Phanerothecium, Ooegyrodactylus, Nothogyrodactylus, Hyperopletes). |
