Polymixia
Polymixia is the only extant genus of the order Polymixiiformes and family Polymixiidae. It contains 12 species, all of which live in deepwater marine environments. 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. Most are relatively small fish, although one species is over in length. They can be considered "living fossils" due to being the only surviving members of the once-diverse order Polymixiiformes.
Classification
There are currently 12 recognized species in this genus:Polymixia berndti C. H. Gilbert, 1905 Polymixia busakhini Kotlyar, 1993 Polymixia carmenae Caixeta, Oliveira & de Melo, 2024 Polymixia fusca Kotthaus, 1970Polymixia hollisterae Grande & Wilson, 2021 Polymixia japonica Günther, 1877 Polymixia longispina S. M. Deng, G. Q. Xiong & H. X. Zhan, 1983Polymixia lowei Günther, 1859 Polymixia melanostoma Fan, Su, Lin, Chang & Lin 2024Polymixia nobilis R. T. Lowe, 1838 Polymixia salagomeziensis Kotlyar, 1991Polymixia sazonovi Kotlyar, 1992Polymixia yuri Kotlyar, 1982The extinct species Polymixia polita Schwarzhans, 2012 is known from fossil otoliths from the early and late Paleocene of Germany and Austria. Another otolith-based taxon that may possibly belong to this genus, Polymixia? harderi 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.