Recent phylogenies have suggested that acoelomorph flatworms might provide insights into the nature of the ancestor of bilaterian animals. However, according to new data acoelomorphs might instead be degenerate deuterostomes closely related to Xenoturbella, muddying the waters of early animal evolution. © 2011 Elsevier Ltd.
Lowe, C. J., & Pani, A. M. (2011, February 22). Animal evolution: A soap opera of unremarkable worms. Current Biology. https://doi.org/10.1016/j.cub.2010.12.017