The role of the middle east in the biogeographical dispersal of host-specific parasites: monogeneans and their cyprinoid fish hosts

Abstract

Aim: This study investigates the diversity and phylogeny of Dactylogyrus species in the Middle East, as well as uncovers the historical dispersal routes and biogeographical contacts of cyprinoid host species using their host-specific parasites. Location: The Middle East. Taxon: Dactylogyrus (Dactylogyridae: Monogenea), Cyprinoidei (Cypriniformes). Methods: More than 1040 cyprinoid fish and their host-specific parasites were sampled in the Middle East. Phylogenetic analyses were conducted using the partial 18S rDNA, 28S rDNA, and complete ITS1 regions for the parasite species from the Middle Eastern species and those retrieved from GenBank, and the biogeographical analysis was performed. The mapping of the morphological characters of the attachment organ (haptor) onto the phylogeny was performed to reveal the patterns of morphological evolution and adaptation. Results: Phylogenetic analyses of Middle Eastern species and those retrieved from GenBank revealed seven major clades of Dactylogyrus parasites. Dactylogyrus species from the Middle East were present in five of these clades, alongside species from Europe, North Africa, and East Asia, emphasising the role of the Middle East, a crossroad of the historical dispersal of cyprinoids, in Dactylogyrus diversification. The deep nodal split of lineages suggests at least two independent dispersion events involving Dactylogyrus parasites from Asia to Europe and Africa. Additionally, mapping the morphological characters illustrated that the evolutionary patterns of haptor adaptation do not fully follow the evolutionary novelty.