New insights on the genus Otoplana Du Plessis, 1889 (Platyhelminthes: Proseriata), with description of two new species from the Canary Islands

Two new species of Otoplana (Proseriata: Otoplanidae) from the Canary Islands are here described: Otoplana norenburgi sp. nov. and Otoplana didomenicoi sp. nov. These new species are distinguished from their congeners by unique features of the sclerotized structures of the copulatory organ, in particular of the aculeus, swollen proximally in O. norenburgi sp. nov. and lanceolate in shape in O. didomenicoi sp. nov. Specimens of the latter species were also found in South Portugal. Canarian and Portuguese specimens show poor genetic distinction based on the markers used, hinting to a remarkable dispersal power for a mesopsammic organism. New information is given on the “accessory male canal”, a putative autapomorphy for the genus Otoplana. Its functions and connections with genital systems are discussed, in the light of new data on the molecular phylogeny of the family Otoplanidae presented. The Mediterranean specimens of Otoplana sequenced, morphologically attributed to O. truncaspina, O. bosporana, O. falcataspina, and O. labronica, did not show genetic distinction, urging for a reconsideration of the status of the Mediterranean taxa.