Danish researchers, writing in PLOS ONE, have described a new genus of deep-sea animal discovered off the coast of Australia. Specimens defy easy placement in any known animal group, while sharing similarities with a group thought to have died out more than 500 million years ago.
Though the specimens of Dendrogramma (stored in ethanol since 1980, making DNA analysis difficult) somewhat resemble the comb jellies and/or jellyfish, they lack many defining characteristics of each group. To quote the paper:
"We can state with considerable certainty that the organisms do not possess cnidocytes, tentacles, marginal pore openings for the radiating canals, ring canal, sense organs in the form of e.g., statocysts or the rhopalia of Scyphozoa and Cubozoa, or colloblasts, ctenes, or an apical organ . . .."
The specimens also lack cilia and gonads, although the latter may simply be a matter of immaturity.
You can read the full paper on PLOS ONE.
Image credit: Just J, Kristensen RM, Olesen J (2014) Dendrogramma, New Genus, with Two New Non-Bilaterian Species from the Marine Bathyal of Southeastern Australia (Animalia, Metazoa incertae sedis) – with Similarities to Some Medusoids from the Precambrian Ediacara. PLoS ONE 9(9): e102976. doi:10.1371/journal.pone.0102976