Essexella is an extinct genus of cnidarian known from Late Carboniferous fossils; it contains a single species, E. asherae. It is one of the most recurrent organisms in the Mazon Creek fossil beds of Illinois;[1] in the Essex biota of Mazon Creek, it consists of 42% of all fossil finds.[2]Essexella was originally described as a jellyfish,[3] but was recently redescribed as a sea anemone. The scientists on the "anemone" side of the debate made a book as early as 2017,[4] but it was ignored until the same authors made a proper scientific paper in 2023.[5]
Another alleged jellyfish, Reticulomedusa, is likely Essexella preserved from different angles. Essexella may have produced the common trace fossil Conostichus.[6]
^ abPalmer, Douglas; Brasier, Martin; Burnie, David; Cleal, Chris; Crane, Peter; Thomas, Barry A.; Buttler, Caroline; Cope, John C. W.; Owens, Robert M. (2009). "Carboniferous". In Ambrose, Jamie; Gilpin, Daniel; Hirani, Salima; Jackson, Tom; Joyce, Nathan; Maiklem, Lara; Marriott, Emma; Nottage, Claire; van Zyl, Miezan (eds.). Prehistoric Life: the Definitive Visual History of Life on Earth (first American ed.). New York City: DK Publishing. p. 62. ISBN978-0-7566-5573-0.
^Selden, Paul; Nudds, John (2012). "Mazon Creek". Evolution of Fossil Ecosystems (second ed.). Manson Publishing Ltd. pp. 94–96. ISBN978-1-84076-623-3.