A new species of symbiotic flatworms, Paracatenulagalateia sp. nov. (Platyhelminthes: Catenulida: Retronectidae) from Belize (Central America)

Abstract

Paracatenula galateia sp. nov. is a mouthless marine catenulid platyhelminth with bacterial intracellular endosymbionts. The worms live in shallow back-reef sands in the Belize Barrier Reef system and are distinguished from the four previously described members of the genus by their large size combined with a ribbon-shaped body and characteristic bipartite inclusions in cells, which are interpreted as sperm. The bacteria are presumed to be sulphur-oxidizing chemoautotrophs. They are found in bacteriocytes which fill the body region (‘trophosome region’) posterior to the brain, whereas the anterior part of the worm (rostrum) is bacteria-free. Phalloidin staining reveals a delicate system of subepitheliar circular and longitudinal muscles and dorsoventral fibres. The serotonergic nervous system consists of a brain at the base of the rostrum and longitudinal fibres extending both anteriorly and posteriorly, the latter being concentrated in a structure called the ‘dorsal cord’.

Keywords:

• Interstitial meiofauna
• intracellular symbiosis
• subtidal sand

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

This work was supported by the Austrian Science Fund (FWF) project 20394-B03 (JO, HG, NL and UD). We thank Renate Hodinka for suggesting the species name. Part of this work was carried out by using the resources of the Computational Biology Service Unit from Cornell University which is partially funded by The Microsoft Corporation. This is contribution 899 from the Carrie Bow Cay Laboratory, Caribbean Coral Reef Ecosystem Program, NMNH, Washington, DC.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Additional information

Notes on contributors

Harald R. Gruber-Vodicka

These authors contributed equally