''Guemesia'' (named after

Martín Miguel de Güemes Martín Miguel de Güemes (8 February 1785 – 17 June 1821) was a military leader and popular caudillo who defended northwestern Argentina from the Spanish royalist army during the Argentine War of Independence. Biography Güemes was born in ...

, whose death bicentenary was in 2021) is a genus of

abelisaurid Abelisauridae (meaning "Abel's lizards") is a family (or clade) of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are foun ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cre ...

Los Blanquitos Formation of

Salta Province Salta () is a Provinces of Argentina, province of Argentina, located in the northwest of the country. Neighboring provinces are from the east clockwise Formosa Province, Formosa, Chaco Province, Chaco, Santiago del Estero Province, Santiago del Es ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. The type and only species is ''Guemesia ochoai'', known from a nearly complete braincase. It is one of the smallest abelisaurids currently known.

Discovery

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''Guemesia'', IBIGEO-P 103, is a small, nearly complete braincase. It was found in the Los Blanquitos Formation, in the Amblayo Valley of Salta Province, Argentina. The specimen was described in 2022 by Agnolín ''et al''. as belonging to a new genus and species of abelisaurid dinosaur, and the first dinosaur of its kind known from the area.

Classification

Agnolín ''et al.'' place ''Guemesia'' as a derived abelisaurid within the clade Brachyrostra.

Paleoecology

''Guemesia'' is known from the Los Blanquitos Formation. The controversial

tetanuran Tetanurae (/ˌtɛtəˈnjuːriː/ or "stiff tails") is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, and coelurosaurs (which includes tyrannosauroids, ornithomimosaurs, compsognathids and maniraptoran ...

theropod ''

Unquillosaurus ''Unquillosaurus'' (meaning "Unquillo river lizard") is a genus of large theropod dinosaur from the Late Cretaceous Los Blanquitos Formation of Salta Province, Argentina. Its precise classification is uncertain, but most researchers consider it ...

'' is also known from this formation, as well as fossils of what may belong to a species of ''

Titanosaurus ''Titanosaurus'' (; ) is a dubious genus of sauropod dinosaurs, first described by Richard Lydekker in 1877.R. Lydekker. (1877). Notices of new and other Vertebrata from Indian Tertiary and Secondary rocks. ''Records of the Geological Survey of ...

''.Arroyo El Morterito
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Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org

References

{{Taxonbar, from=Q110886909 Abelisauridae Dinosaur genera Maastrichtian dinosaurs Fossil taxa described in 2022 Dinosaurs of Argentina