The bacterium is an endosymbiotic prokaryote living in the gut of a marine worm called Xenoturbella, a creature also unique to the Gullmarsfjord. Researchers identified two types of endosymbiotic bacteria (Xenoturbellida, Bilateria). They say other scientists should consider the new endosymbionts "when interpreting the poorly understood ecology and evolution of Xenoturbella."
the Bacteria's host, the Xenoturbella worm, has the size of a thumbnail and possesses a unique body plan, with no brain and no reproductive or sensory organs. This unique creature is invaluable for studies of the early evolution of the animal kingdom, and has drawn researchers from all over the world to the Sven Lovén Centre for Marine Sciences in Kristineberg ever since it was discovered.
The unique Xenoturbella, found only in the Gullmarsfjord, is the host for the new bacteria.
(Photo Credit: Mattias Obst, University of Gothenburg)
Citation: Kjeldsen et al., 'Two Types of Endosymbiotic Bacteria in the Enigmatic Marine Worm Xenoturbella bockiApplied and Environmental Microbiology, April 2010, 2657-2662, 76(8) doi:10.1128/AEM.01092-09