Treasure island: DNA data reveals unknown diversity in Cuban freshwater planarians (Platyhelminthes: Tricladida)

Abstract

. Freshwater planarians constitute an important component in aquatic ecosystems as predators. They are, nonetheless, delicate animals used as indicators of water quality. This group has been little studied in The Antilles, where only seven species of Girardia Ball, 1974 have been reported. Those records date from the last two centuries and were identified based on morphology, leaving several specimens unidentified. Furthermore, the anatomical similarities among species and the lack of the copulatory apparatus in fissiparous populations make it necessary to use molecular data to perform accurate species delimitations and phylogenetic studies. The Cuban archipelago is the reservoir of the highest species diversity in the Caribbean. However, only one species of freshwater triclad has been described, Girardia cubana (Codreanu & Balcesco, 1973), which is endemic to Cuba. Recent samplings in the western part of the island molecularly identified Girardia sinensis Chen & Wang, 2015. At present, we are performing broad samplings all around Cuba. As a first result, we here present a phylogeny-based identification of freshwater planarians, collected in four localities of eastern Cuba, inferred using nuclear and mitochondrial markers. The presence of G. sinensis in the eastern part of the island is reported and two other lineages of the genus are identified, at least one could be a new species. Moreover, we found a lineage belonging to Cavernicola, of which there are no previous records in The Antilles. These findings support that the planarian richness of Cuba has been underestimated and new species could be described, providing relevant biogeographic information about the group in the Caribbean.