Ellimmichthys Explained

Ellimmichthys is an extinct genus of freshwater clupeomorph fish belonging to the order Ellimmichthyiformes, of which it is the type genus. It was a distant relative of modern herrings and anchovies.^[1] It inhabited freshwater rift lakes in the supercontinent of West Gondwana (comprising modern South America and Africa) during the Early Cretaceous, and fossil remains are known from formations in both South America (Brazil) and Africa (Equatorial Guinea).^{[2] [3]}

Taxonomy

The following species are known:^[4]

• †E. longicostatus (Cope, 1886) - Berriasian/Valanginian of Bahia, Brazil (Candeias Formation) (=Diplomystus longicostatus Cope, 1886) (type species)
• †E. goodi (Eastman, 1912) - Aptian/Albian of Equatorial Guinea (Cocobeach Formation) (=Diplomystus goodi Eastman, 1912, D. elberti Weiler, 1922, Ellimma guineensis Gayet, 1989)^[5]
• †E. spinosus de Figuereido & Gallo, 2021 - Berriasian/Valanginian of Bahia, Brazil (Candeias Formation)

Another species E. maceioensis Malabarba et al, 2004 from the Aptian-aged Maceió Formation of Alagoas, Brazil likely does not belong to this genus as it does not display diagnostic morphological characteristics.^[6] However, the genus as a whole may also be paraphyletic with respect to Ellimma.^[7]

The sister genus to Ellimmichthys is thought to be Eoellimmichthys, a marine paraclupeid that lived much later during the Early Eocene, with fossils known from Monte Bolca, Italy. Eoellimmichthys is thought to have been the last surviving paraclupeid, and the last surviving marine ellimmichthyiform as a whole.

Notes and References

1. Web site: PBDB Taxon . 2024-08-12 . paleobiodb.org.
2. de Figueiredo . Francisco J. . Gallo . Valéria . 2021-01-01 . Revision of †Ellimmichthys longicostatus (Clupeomorpha: †Ellimmichthyiformes) from the Lower Cretaceous of Brazil with comments on the taxonomy of related species . Journal of South American Earth Sciences . 105 . 103006 . 10.1016/j.jsames.2020.103006 . 0895-9811.
3. Marramà . Giuseppe . Bannikov . Alexandre F. . Kriwet . Jürgen . Carnevale . Giorgio . 2019 . Cavin . Lionel . An Eocene paraclupeid fish (Teleostei, Ellimmichthyiformes) from Bolca, Italy: the youngest marine record of double-armoured herrings . Papers in Palaeontology . en . 5 . 1 . 83–98 . 10.1002/spp2.1230 . 2056-2799 . 6392134 . 30854219.
4. Alvarado-Ortega . Jesús . Melgarejo-Damián . María del Pilar . Alvarado-Ortega . Jesús . Melgarejo-Damián . María del Pilar . 2017 . Paraclupea seilacheri sp. nov., a double armored herring (Clupeomorpha, Ellimmichthyiformes) from the Albian limestones of Tlayúa quarry, Puebla, Mexico . Revista mexicana de ciencias geológicas . en . 34 . 3 . 234–249 . 10.22201/cgeo.20072902e.2017.3.528 . 1026-8774. free .
5. Murray . A.M. . 2000 . The Palaeozoic, Mesozoic and Early Cenozoic fishes of Africa . Fish and Fisheries . en . 1 . 2 . 111–145 . 10.1046/j.1467-2979.2000.00015.x . 1467-2960.
6. Polck . Márcia Aparecida dos Reis . Gallo . Valéria . de Figueiredo . Francisco J. . Viana . Samuel Magalhães . dos Santos . Viviane Sampaio Santiago . de Queiroz Neto . João Villar . Jahnert . Ricardo Jorge . 2020-03-01 . †Ellimma longipectoralis sp. nov. (Teleostei: Clupeomorpha: †Ellimmichthyiformes) from the Aptian of the Santos Basin, southeastern Brazil . Journal of South American Earth Sciences . 98 . 102318 . 10.1016/j.jsames.2019.102318 . 0895-9811.
7. de Figueiredo . Francisco J. . Gallo . Valéria . 2023-02-01 . Caboellimma, a new genus for "Ellimma" cruzae Santos, 1990, an ellimmichthyiform fish (Teleostei: Clupeomorpha) from the Cabo Formation (Lower Cretaceous) of the Pernambuco-Paraíba Basin, north-east Brazil . Cretaceous Research . 142 . 105393 . 10.1016/j.cretres.2022.105393 . 0195-6671.