MSc Student
Advisor: Elisabeth Haring
Unit for Integrative Zoology, Department of Evolutionary Biology
University of Vienna &
Natural History Museum Vienna
Abstract
Matthäus Greilhuber1, Bernhard Egger2, Elisabeth Haring3
1 E-mail: mgreilhuber@gmail.com
2 E-mail: bernhard.egger@uibk.ac.at
3 E-mail: elisabeth.haring@nhm-wien.ac.at
The main aim of the study presented is to generate reference DNA barcodes for some of the freshwater turbellarian species occurring in the territory of Austria. The turbellarians are the Platyhelminthes excluding the monophyletic, exclusively parasitic Neodermata, and are also referred to as the free-living flatworms, although not all turbellarians are free-living. Around 200 species are estimated to occur in Austria. They are of high interest because taxonomic expertise with turbellarians is currently lacking in Austria even though they are a major component of ecosystems.
Turbellarians were collected in eastern Austria in various freshwater habitats using a plankton net and subsequently investigated alive using stereo and compound microscopes. Features were photographed or drawn to allow for subsequent determination. After that, some specimens were fixed in 96% ethanol for DNA analysis, and some in Bouin’s fluid for histology. Histological serial sections of some specimens were made, and a reconstruction of the genitals of at least one specimen is planned. In the molecular genetic analysis, partial sequences of the nuclear 18S and 28S rRNA genes are used as barcoding regions.
Amplification of the barcoding fragment in both the 18S and 28S rRNA gene was highly successful, and a single primer pair each is applicable over all the orders of turbellarians. Identification of specimens to the species level is one of the main challenges. A cautious approach to identification is taken, whereby the determination is based on morphology rather than existing sequences in the databases, and if the determination of the species is ambiguous, the identification is retained at the lowest level that can be determined with certainty (e.g., the genus). The specimens found represent at least 31 genera of Turbellarians, as determined by morphology, and even more species. About half of the genera found belong to the taxon Rhabdocoela, which attests to its great importance and diversity in freshwater ecosystems.
Keywords: Platyhelminthes, genetics, biodiversity, Rhabdocoela, Tricladida
