Polymixia Temporal range: Late Cretaceous occurrence Possible | |
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Stout beardfish (P. nobilis) | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Polymixiiformes |
Family: | Polymixiidae |
Genus: | Polymixia R. T. Lowe, 1838 |
Type species | |
Polymixia nobilis R. T. Lowe, 1838 |
Polymixia is the only extant genus of the order Polymixiiformes and family Polymixiidae. It contains 10 species, all of which live in deepwater marine environments. [1] They are found in tropical and subtropical waters of the Atlantic, Indian and western Pacific Oceans. They are bottom-dwelling fish, found down to about 800 m (2,600 ft). Most are relatively small fish, although one species is over 40 cm (16 in) in length. [2] They can be considered "living fossils" due to being the only surviving members of the once-diverse order Polymixiiformes. [3]
There are currently 12 recognized species in this genus: [1]
The extinct species Polymixia polita Schwarzhans, 2012 is known from fossil otoliths from the early and late Paleocene of Germany and Austria. [6] Another otolith-based taxon that may possibly belong to this genus, Polymixia? harderi (Schwarzhans, 2003) is known from the late Maastrichtian and early Paleocene of Denmark, in addition to a potential earlier record from the Campanian of North Carolina, USA; this may suggest Late Cretaceous origins for the genus. [7] [8]