Essexella

{{Short description|Extinct cnidarian}}

{{Speciesbox

| fossil_range = {{fossil range|Late Carboniferous|ref={{cite book | chapter=Carboniferous | title=Prehistoric Life: the Definitive Visual History of Life on Earth | publisher=DK Publishing | author=Palmer, Douglas | author2-link=Martin Brasier | author5-link=Peter Crane | last2=Brasier | first2=Martin | last3=Burnie | first3=David | last4=Cleal | first4=Chris | last5=Crane | first5=Peter | last6=Thomas | first6=Barry A. | last7=Buttler | first7=Caroline | last8=Cope | first8=John C. W. | last9=Owens | first9=Robert M. | year=2009 | edition=first American | location=New York City | page=62 | isbn=978-0-7566-5573-0 | editor-last=Ambrose | editor-first=Jamie | editor2-last=Gilpin | editor2-first=Daniel | editor3-last=Hirani | editor3-first=Salima | editor4-last=Jackson | editor4-first=Tom | editor5-last=Joyce | editor5-first=Nathan | editor6-last=Maiklem | editor6-first=Lara | editor7-last=Marriott | editor7-first=Emma | editor8-last=Nottage | editor8-first=Claire | editor9-last=van Zyl | editor9-first=Miezan }}}}

| image = Essexella asherae.JPG

| image_caption = Essexella asherae fossil on display at the Museo Civico di Storia Naturale di Milano

| genus = Essexella

| parent_authority = Foster, 1979

| species = asherae

| authority = Foster, 1979

}}

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;{{cite book | chapter=Carboniferous | title=Prehistoric Life: the Definitive Visual History of Life on Earth | publisher=DK Publishing | author=Palmer, Douglas | author2-link=Martin Brasier | author5-link=Peter Crane | last2=Brasier | first2=Martin | last3=Burnie | first3=David | last4=Cleal | first4=Chris | last5=Crane | first5=Peter | last6=Thomas | first6=Barry A. | last7=Buttler | first7=Caroline | last8=Cope | first8=John C. W. | last9=Owens | first9=Robert M. | year=2009 | edition=first American | location=New York City | page=62 | isbn=978-0-7566-5573-0 | editor-last=Ambrose | editor-first=Jamie | editor2-last=Gilpin | editor2-first=Daniel | editor3-last=Hirani | editor3-first=Salima | editor4-last=Jackson | editor4-first=Tom | editor5-last=Joyce | editor5-first=Nathan | editor6-last=Maiklem | editor6-first=Lara | editor7-last=Marriott | editor7-first=Emma | editor8-last=Nottage | editor8-first=Claire | editor9-last=van Zyl | editor9-first=Miezan }} in the Essex biota of Mazon Creek, it consists of 42% of all fossil finds.{{cite book | first1=Paul | last1=Selden | chapter-url=https://books.google.com/books?id=LgdL9ZP2ftgC&pg=PA94 | title=Evolution of Fossil Ecosystems | publisher=Manson Publishing Ltd | last2=Nudds | first2=John | year=2012 | edition=second | pages=94–96 | isbn=978-1-84076-623-3 | chapter=Mazon Creek}} Essexella was originally described as a jellyfish,{{Citation |last=Foster |first=Merrill W. |title=Soft-Bodied Coelenterates in the Pennsylvanian of Illinois |date=1979-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780125196505500163 |work=Mazon Creek Fossils |pages=191–267 |editor-last=Nitecki |editor-first=Matthew H. |access-date=2023-03-10 |publisher=Academic Press |language=en |doi=10.1016/b978-0-12-519650-5.50016-3 |isbn=978-0-12-519650-5}} but was recently redescribed as a sea anemone.{{Cite journal |last1=Plotnick |first1=Roy E. |last2=Young |first2=Graham A. |last3=Hagadorn |first3=James W. |date=8 March 2023 |editor-last=Korn |editor-first=Dieter |title=An abundant sea anemone from the Carboniferous Mazon Creek Lagerstӓtte, USA |journal=Papers in Palaeontology |language=en |volume=9 |issue=2 |doi=10.1002/spp2.1479 |s2cid=257447889 |issn=2056-2799|doi-access=free |bibcode=2023PPal....9E1479P }}

Another alleged jellyfish, Reticulomedusa, is likely Essexella preserved from different angles. Essexella may have produced the common trace fossil Conostichus.{{Cite journal |last1=Plotnick |first1=Roy E. |last2=Young |first2=Graham A. |last3=Hagadorn |first3=James W. |date=8 March 2023 |editor-last=Korn |editor-first=Dieter |title=An abundant sea anemone from the Carboniferous Mazon Creek Lagerstӓtte, USA |journal=Papers in Palaeontology |language=en |volume=9 |issue=2 |doi=10.1002/spp2.1479 |s2cid=257447889 |issn=2056-2799|doi-access=free |bibcode=2023PPal....9E1479P }}