Taxonomy and phylogeny of Koinocystididae (Platyhelminthes, Kalyptorhynchia), with the description of three new genera and twelve new species

The taxon Koinocystididae is the third most species-rich family within Eukalyptorhynchia. However, its diversity and phylogeny have been largely neglected in former studies. We introduce three new genera twelve species of including Simplexcystis asymmetrica gen. n. sp. n., Galapagetula cubensis eight Reinhardorhynchus two Itaipusa. This raises total number from 51 to 63. also report on distribution records for six known species: I. divae (Cuba, Panama New Caledonia), karlingi (Sardinia Lanzarote), riegeri comb. (Cuba), R. ruffinjonesi (Cuba Panama), Utelga heinckei U. pseudoheinckei (Sardinia). characterised by a male duct running eccentrically through copulatory bulb, lack any hard structures system, bursa, fact that epithelia female, male, part common atrium are covered brush border. has caudal gonopore, divisa-type bulb with an unarmed penis papilla, female without sphincter. Itaipusa differ their congeners detailed structure especially associated it. In molecular phylogenetic analysis based all available 18S 28S rDNA sequences koinocystidids, we found support monophyly genus Marcus, 1949. not monophyletic sinensis forms clade Rhinolasius dillonicus, while other armed hooks form together Sekerana stolzi. As type (I. divae) neither these clades, erected (Koinogladius n.) one having hook-bearing (Reinhardorhynchus n.), respectively. Whether remaining monophylum remains uncertain.