Maliamia ("Malian

bowfin The bowfin (''Amia calva'') is a bony fish, native to North America. Common names include mudfish, mud pike, dogfish, grindle, grinnel, swamp trout, and choupique. It is regarded as a relict, being the sole surviving species of the Halecomorphi ...

") is an extinct genus of amiid

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

from the Early

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

, known from fragmentary remains found in the Tamaguélelt Formation of

Mali Mali (; ), officially the Republic of Mali,, , ff, 𞤈𞤫𞤲𞥆𞤣𞤢𞥄𞤲𞤣𞤭 𞤃𞤢𞥄𞤤𞤭, Renndaandi Maali, italics=no, ar, جمهورية مالي, Jumhūriyyāt Mālī is a landlocked country in West Africa. Mali ...

. It was described in 1989, based on fossils recovered by three separate expeditions in 1975, 1979–80, and 1981. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''Maliamia gigas,'' named in reference to its large size. Maliamia is currently the youngest known member of

Vidalamiinae The Amiidae are a family of basal ray-finned fishes. The bowfin is the only species to survive today, although additional species in all four subfamilies of Amiidae are known from Jurassic, Cretaceous, and Eocene fossils. Bowfins are now found ...

, an extinct group of bowfin fish that lived from the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

to the Early Eocene.

Description

''M. gigas'' is known from isolated jaw remains including

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

vomer The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxill ...

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

e, and

dentaries In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

. These fragments lack teeth due to post-mortem wear, but empty tooth sockets remain, and their arrangement implies that ''M. gigas'' had a single row of teeth. Estimates put the body length of ''M. gigas'' between 1.8 (based on ''

Calamopleurus ''Calamopleurus'' is an extinct genus of bowfins, comprising three species: ''C. cylindricus'' and ''C. mawsoni'' from Brazil and ''C. africanus'' from Africa Africa is the world's second-largest and second-most populous continent, af ...

'') and 3.5 meters (based on ''

Amia Amia, AMIA, or AMiA may refer to: * ''Amia'' (fish), a genus of fish *American Medical Informatics Association * Anglican Mission in the Americas *Asociación Mutual Israelita Argentina, a Jewish community center in Buenos Aires, Argentina **AMIA ...

''), making it the largest known member of Vidalamiinae.

Paleoenvironment

Fossils of ''Maliamia'' are known from shallow marine

phosphorite Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxi ...

s. During the Eocene, much of northwest

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

was covered by the Trans-Saharan Seaway, an inland sea estimated to have been approximately 50 meters deep. Global temperatures and the sea level were higher than they are today, and Maliamia lived in warm, tropical waters. Other fishes from its environment included '' Pycnodus jonesae'', '' Lavocatodus giganteus'', '' Myliobatis wurnoensis'', '' Stratodus apicalis'', '' Nigerium tamaguelense,'' and '' Brychaetus sp''. Additionally, it shared its environment with reptiles such as the giant

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

snake Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...

'' Palaeophis colossaeus'' which was, like ''Maliamia,'' among the biggest species in its

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

. As sea levels rose and fell throughout the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

and early

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

, the Trans-Saharan Seaway of Mali experienced intermittent isolation from major seas, which may have made the ecosystem an aquatic center for

endemism Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

where organisms like ''Maliamia'' and ''Palaeophis'' were selected for gigantism.

References

{{Taxonbar, from=Q491934 Fossils of Mali Amiiformes Fossils of Africa Eocene Africa Fossil taxa described in 1989 Eocene fish Paleogene fish Paleogene Africa Prehistoric ray-finned fish genera