Two new Dactylogyrus species (Monogenea: Dactylogyridae) D. angorae and D. turcicus from Capoeta angorae and C. mauricii endemic fishes in Turkey

Two new Dactylogyrus spp., D. angorae and D. turcicus have been described from the gills of the endemic cyprinid fishes, Capoeta angorae and C. mauricii from the Anatolian Region of Turkey. The shape of the anchors, hooks and the copulation organ of both species differ from those of the Dactylogyrus spp. found on other Capoeta species known from the Ponto-Caspian and Tigris-Euphrates regions.

Dactylogyrus fraternus Wagener, 1909 (Monogenea: Dactylogyridae) Parasitic on Alburnus alburnus (Cyprinidae) from Turkey

Dactylogyrus species are a group of monogenean gill parasites that are highly specific to freshwater fishes; represents the most dominant genus among the Monogenea with regard to host distribution and location. They were sampled 14 species from more than 27 host collected in Turkey. Among these dactylogyrid parasites, Dactylogyrus fraternus could be described and illustrated from specimens collected from gills of a cyprinid fish, bleak Alburnus alburnus, in Enne Dam reservoir from Kutahya, Turkey. Diagnostic characters of this species are the tegument of trunk showing annulations, except on the cephalic region, and copulatory complex comprising sclerotized, basal part broad, the tube which is long and hard. The purpose of the present study was to determine, on the whole, the body structure of the Dactylogyrus fraternus in bleak.

Dactylogyrus species parasitizing European Barbus species: morphometric and molecular variability

SUMMARYThe aims of the study were (1) to describe the Dactylogyrus communities living on selected South European Barbus species, (2) to analyse morphometric variability of their attachment and reproductive organs, and (3) to perform molecular phylogenetic analyses, in order to investigate the mode of speciation in Dactylogyrus species parasitizing congeneric hosts. In Bulgaria, Dactylogyrus crivellius, D. dyki and D. petenyi were found on B. balcanicus, and D. dyki on B. cyclolepis. In Spain, Dactylogyrus carpathicus and D. dyki were detected on B. meridionalis. Morphometric analyses of D. dyki revealed significant differences in the attachment and reproductive organs when individuals from different Barbus species were compared. Two monophyletic groups were recognized from the molecular phylogenetic analyses: the first included D. carpathicus and D. crivellius which have large body size and anchors, with a weakly supported basal position of D. malleus from B. barbus; the second included D. dyki and D. petenyi which have small body and anchor sizes. The comparison of host and parasite phylogenies did not indicate the intrahost speciation. Intraspecific molecular variability was found between individuals of D. dyki and D. carpathicus from different Barbus species, suggesting the need for a taxonomic revision for these species.

Morphometric correlates of host specificity in Dactylogyrus species (Monogenea) parasites of European Cyprinid fish

We test the hypothesis that living on larger fish may impose constraints, i.e. the need to develop large attachment organs, related to the necessity to remain attached on large gills. For this, we compiled data on body size and morphometric measurements of attachment organs of 44 Dactylogyrus species (ectoparasites with direct life-cycle) from 19 cyprinid species. Nineteen dactylogyrid species were considered as specialists (infecting only 1 host species) and 25 as generalists (infecting more than 1 species). The lack of phylogenetic information lead us to perform comparative analyses using raw values and independent contrasts obtained by random phylogenies. Our results show that rich parasite communities are formed by specialists and generalists whereas poor communities are composed mainly of generalist parasites. Moreover, specialists are found on larger hosts, which may reflect a specialization on a predictable resource, as larger fish live longer and offer large gills for parasite colonization. Parasite specialization is shown to be linked with adaptation of attachment organs to their fish hosts. Two morphometric variables of the attachment organ, the total length of anchor and length of base of anchor, were positively correlated with host length for specialists.

Microhabitat distribution and coexistence of Dactylogyrus species (Monogenea) on the gills of roach

SUMMARYThe Dactylogyrus fauna was studied from the gills of 293 roach between February 1988 and April 1989. Roach were caught from three interconnected lakes in Central Finland. Nine Dactylogyrus species were found. Of these the seven most abundant were used for studying the abundance of species on different gill-arches, niche breadth and niche overlap between the species. It was found that all species had a species-specific preference for certain gill-arches. The total abundances of all the species went through distinct seasonal changes, peaking during the spring and early summer. Some seasonal variation was also exhibited in gill-arch preferences. Niche breadth and species overlap were mostly higher during the period of peak occurrence of the various species, but in the case of some species they appeared to be unrelated to abundance, indicating possible niche restriction by other species. Most significant was the restriction of D. micracanthus to the fourth gill-arch during the period of peak occurrence of D. similis. Experimental work is needed to verify the reasons for variations in the microhabitat distribution of certain Dactylogyrus species.