Symbion
animals, with a single species, S. pandora. It was discovered in 1995 by Reinhardt Kristensen and Peter Funch on the mouthparts of the Norwegian lobster Nephrops norvegicus. Symbion does not appear to have any especially close relatives, and so was given its own phylum, called Cycliophora.
The phylogenetic position of Symbion remains unclear. Originally the phyla Ectoprocta and Entoprocta were considered possible relatives of Symbion, thanks to structural similarities. However, genetic studies suggest Symbion may be closer to the Gnathifera.
