A New Spiralian Phylogeny Places the Enigmatic Arrow Worms among Gnathiferans (Current Biology)

Marlétaz et al. used new data and refined methods to improve the phylogenetic placement of chaetognaths, an enigmatic group of marine animals. They relate to gnathiferans, a sister group of other spiralians, and include rotifers and gnathostomulids. Spiralians are subdivided in three main clades (including Tetraneuralia and Lophotrochozoa).