| Ellimmichthyiformes Temporal range:
| |
|---|---|
| |
| Diplomystus dentatus from Wyoming | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Superorder: | Clupeomorpha |
| Order: | †Ellimmichthyiformes Grande, 1982 |
| Type genus | |
| †Ellimmichthys Jordan, 1919
| |
| Families | |
The Ellimmichthyiformes, also known as double-armored herrings, are an extinct order of ray-finned fish known from the Early Cretaceous to the Oligocene. They were the sister group to the extant true herrings, shad and anchovies in the order Clupeiformes, with both orders belonging to the suborder Clupeomorpha.[1]
A highly successful group throughout the Cretaceous, they were found worldwide and are known to have inhabited both marine and freshwater habitats. They appear to have been a largely marine group for most of their history, with the first freshwater lineages appearing during the Late Cretaceous.[2]
Shortly after the origin of the Ellimmichthyiformes in the Early Cretaceous, the Mediterranean portion of the Tethys Ocean appears to have been a major center of diversification for them, as the majority of fossils of this group are known from there. Following this, they saw an explosion in diversity during the Cenomanian, possibly due to the high sea levels of the Tethys at the time and the resulting impact on geography and food distribution, with the group evolving numerous different body plans.[2][3] However, they were devastated by the Cretaceous–Paleogene extinction event and saw a drastic reduction in range. Only a few freshwater species in the genera Diplomystus and Guiclupea survived primarily in North America and China (although the unusual Gasteroclupea of South America appears to have briefly survived into the Paleocene), including Diplomystus dentatus of the famous Green River Formation. A few marine lineages survived in the Tethys Ocean near modern Italy, such as "Diplomystus" trebicianensis in the Paleocene and Eoellimichthys, the last marine ellimmichthyiform, during the Eocene. The last surviving ellimmichthyiform, Guiclupea, was a freshwater species that occurred in southern China during the Oligocene, representing the youngest member of the group.[3][4]
- ^ Nelson, Joseph S.; Grande, Terry C.; Wilson, Mark V. H. (2016-02-22). Fishes of the World. Wiley. doi:10.1002/9781119174844. ISBN 978-1-118-34233-6.
- ^ a b Boukhalfa, Kamel; Wu, Feixiang; Ben Ali, Walid; Fang, Gengyu (2018-09-03). "A new paraclupeid fish (Clupeomorpha: Ellimmichthyiformes) from the Lower Cretaceous Sidi Aich Formation of southern Tunisia: phylogenetic and paleobiogeographic implications". Journal of Vertebrate Paleontology. 38 (5): e1529675. Bibcode:2018JVPal..38E9675B. doi:10.1080/02724634.2018.1529675. ISSN 0272-4634. S2CID 91457179.
- ^ a b Marramà, Giuseppe; Bannikov, Alexandre F.; Kriwet, Jürgen; Carnevale, Giorgio (2019). Cavin, Lionel (ed.). "An Eocene paraclupeid fish (Teleostei, Ellimmichthyiformes) from Bolca, Italy: the youngest marine record of double-armoured herrings". Papers in Palaeontology. 5 (1): 83–98. Bibcode:2019PPal....5...83M. doi:10.1002/spp2.1230. ISSN 2056-2799. PMC 6392134. PMID 30854219.
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