''Atractosteus grandei'' is an extinct species of

gar Gars are members of the family Lepisosteidae, which are the only surviving members of the Ginglymodi, an ancient holosteian group of ray-finned fish, which first appeared during the Triassic, over 240 million years ago. Gars comprise seven livin ...

in the family

Lepisosteidae Gars are members of the family Lepisosteidae, which are the only surviving members of the Ginglymodi, an ancient holosteian group of ray-finned fish, which first appeared during the Triassic, over 240 million years ago. Gars comprise seven livin ...

. Remains have been found in Lower

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 ...

sediments from

North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the Native Americans in the United States, indigenous Dakota people, Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north a ...

. ''A. grandei'' belonged to the genus ''Atractosteus'' which includes modern day species of gars such as the giant

alligator gar The alligator gar (''Atractosteus spatula'') is a ray-finned euryhaline fish related to the bowfin in the infraclass Holostei . It is the largest species in the gar family, and among the largest freshwater fish in North America. The fossil reco ...

(''Atractosteus spatula'') and the

tropical gar The tropical gar (''Atractosteus tropicus'') is a species of fish from Central America, where it is found in the Pacific and Atlantic drainages from southern Mexico to Costa Rica. In Central America it is known as ''gaspar'' and in Mexico it is k ...

(''Atractosteus tropicus'').

Description

''A. grandei'' was a large-bodied gar, reaching in body length. The species exited approximately 1500–2500 years after the

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...

that killed of most large life on Earth. ''Atractosteus grandei'' was a macropredator. It had rhomboid

ganoid A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as w ...

(fish) scales, a weakly ornamented

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

roof and opisthocoelous

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

. The body shape of ''A. grandei'' had a slender torpedo like body with long snouts and lots of teeth used to hunt prey of

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

ecosystems.

Discovery

''Atractosteus grandei'' was discovered in Williston Basin of North Dakota in June 2022. The fossil was 15 centimeters above the Cretaceous–Paleogene extinction event boundary about 66 million years ago making ''A. grandei'' the oldest known

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

fossil in the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

. The discovery of ''Atractosteus grandei'' suggest that freshwater ecosystems recovered quickly after the asteroid impact that killed of the non-avian dinosaurs.

References

{{Taxonbar, from=Q113541430 Lepisosteidae Prehistoric fish

Description

Discovery

See also

References