Project R-1501

Biodiversity and phylogeny of the Typhloplanidae Graff, 1905 (Rhabdocoela: Dalytyphloplanida) (Research)

With about 300 species described, the Typhloplanidae is one of the most species-rich families of free-living flatworms. However, it is not only the high number of species that makes this taxon worth studying, but especially the high diversity in morphology and ecology that representatives of this taxon exhibit. Most of the species only occur in freshwater, while others are exclusively found in marine environments. Most interesting, however, is that many species have adapted to a life in semi-terrestrial habitats, which is very exceptional for free-living flatworms. Several species also live in permanent association with unicellular green algae, which are situated within the animal itself (endosymbiosis). Finally, the group occurs all over the world, which raises questions about the origin of this worldwide distribution, as these animals are not capable of long-range dispersion. Several groups within the Typhloplanidae are notorious because of the fact that the species are almost indistinguishable based on morphology alone. To a large extent this hampers the study of the biodiversity and ecology of these interesting animals. A thorough molecular study of these groups is, therefore, necessary to facilitate species delimitation. Finally, several species of Typhloplanidae apparently have a wide biogeographical distribution, occurring on several, if not all, continents. Probably these species represent complexes of species that are impossible to distinguish morphologically (so-called cryptic biodiversity), which makes the group an ideal subject for the evaluation of the DNA-barcoding technique, a hot-topic within present biodiversity research. In this project we put forward following objectives: 1. To elucidate phylogenetic relationships of and within the Typhloplanidae, in order to find an answer to the question how the worldwide distribution, the different habitat preferences and the symbiosis with algae originated. 2. To delineate species within problematic groups, using both molecular markers and morphology. 3. To analyse some deliberately chosen putative species-complexes, including an evaluation of DNA-barcoding in free-living flatworms. In order to obtain satisfying results, the analyses will be done using as many species as possible, which need to be collected at different localities. This will undoubtedly lead to the discovery of many new species, which need to be described in several publications. The analyses will be conducted using a combined morphological and molecular approach, with different genes. The molecular phylogenetic study, aiming at solving important ecological and biogeographical questions as explained above, and DNA-barcoding are both hot-topics in modern phylogenetic and biodiversity research, and will undoubtedly lead to several publications in high quality journals. This project therefore ensures a high-level output, both as to quantity and quality.

01 January 2009 - 31 December 2012