Species depauperate communities and low abundances of monogenean gill parasites at the edge of the natural distribution range of their cichlid hosts in northern Africa

In Morocco, no work has been carried out on parasitic monogeneans of cichlid fish as far. An examination of the gills of 375 fish from three native species of Cichlidae: Oreochromis aureus, Coptodon zillii and Coptodon guineensis from different localities, revealed the presence of two monogenean species (1328 monogenean specimens were recovered from 56 fish specimens) belonging to the family Dactylogyridae and to the genus Cichlidogyrus : three morphotypes of C. cirratus were identified from O. aureus and C. zillii ; and C. cubitus was identified from C. guineensis . This is the first time that these monogeneans were collected and identified in Morocco. In addition, O. aureus was revealed as a new host for C. cirratus . The low parasite species richness and intensity, appear to support the enemy release hypothesis, and have probably promoted the lateral transfer of parasites in natural populations between O. aureus and C. zillii , and the synxenic diversification of C. cirratus .