Ellimma
From Wikipedia, the free encyclopedia
Ellimma is an extinct genus of freshwater clupeomorph fish belonging to the order Ellimmichthyiformes. It was a distant relative of modern herrings and anchovies.[1] Fossil remains are known from the Early Cretaceous of South America.
| Ellimma Temporal range: | |
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| Fossil specimens of E. branneri | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | †Ellimmichthyiformes |
| Family: | †Paraclupeidae |
| Genus: | †Ellimma Jordan, 1913 |
| Species | |
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| Synonyms | |
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Two species are known:
- E. branneri Jordan, 1913 (type species) - Early Cretaceous (Aptian) of Alagoas, Brazil (Muribeca Formation)[2][3]
- E. longipectoralis Polck et al., 2020 - Aptian of offshore southeastern Brazil (Barra Velha Formation of Santos Basin)[4]
The species E. longipectoralis was described from nearly complete fossil specimens within a drill core from oil exploration, recovered 200 kilometres (120 miles) offshore at a depth of 5,500 metres (18,000 ft) below sea level. It represents the first articulated vertebrate specimen known from the offshore Santos Basin and a significant southwards range extension for the genus. It appears to have inhabited an alkaline shallow lake environment.[4]
The genus name Ellimma was coined in 1913 to replace the name Ellipes, which was preoccupied by a modern genus of orthopteran insect.[5] Ellipes was previously coined in 1910 by Jordan for a fossil herring-like fish from Brazil described by Edward Drinker Cope as Diplomystus longicostatus.[6] A new species of Ellima, E. branneri, was also described alongside the genus, which was fixed as the type species of the genus.[5] In 1919, Jordan noted the significant morphological differences between E. branneri and E. longicostatus, most notably the sharply elevated back of the latter, and placed the latter species in the new genus Ellimmichthys.[5] However, the genus Ellimma as a whole may be paraphyletic with respect to Ellimmichthys, as some phylogenies show both species in both genera being sister to one another. The species E. cruzae from the Cabo Formation of Brazil is now placed in its own genus, Caboellimma.[7] The species E. elmodenae from the Late Miocene of California, US, initially also placed in Ellimma by Jordan, is now placed in the true herring genus Xyrinius.[5][8]