''Hulettia'' is an extinct genus of

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 ...

found in the

Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic, Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandsto ...

in the western

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, measuring approximately three to four inches in length. This fish

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

contains one species, ''H. americana''. Its body was covered in thick prominent scales, and its name is based on

Hulett, Wyoming Hulett is a town in Crook County, Wyoming, United States. The population was 309 at the 2020 census. Geography Hulett is located at (44.683014, -104.600387). According to the United States Census Bureau, the town has a total area of , all lan ...

, a locale which is near the

. Discovered specimens show evidence of predation upon the smaller species of fish '' Todiltia'' that inhabited the Jurassic Lake Todilto, and another specimen discovered in the

Bathonian In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age. Strat ...

coastal sandstone, in the

Sundance Formation The Sundance Formation is a western North American sequence of Middle Jurassic to Upper Jurassic age Dating from the Bathonian to the Oxfordian, around 168-157 Ma, It is up to 100 metres thick and consists of marine shale, sandy shale, sandst ...

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...

. Both specimens are complete skeletons with no fragmentary remains or dubious anomalies amongst the bones recovered.

Description

''Hulettia'' reached their maximum size of . It is believed that the colossal deposits of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

that are found in Todilto Formation and the

deterred other organisms from the area, and isolated the two species, protecting them from predation and trophic competition until their disappearance from the fossil record in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

.https://nmgs.nmt.edu/publications/guidebooks/downloads/54/54_p0179_p0189.pdf New Mexico Geological Society Guidebook, 54th Field Conference, Geology of the Zuni Plateau, 2003, p. 179-189.

References

External links

Bony fish in the online Sepkoski Database
{{Taxonbar, from=Q5935653 Prehistoric neopterygii Morrison fauna

Description

See also

References

External links