Guemesia

Say it: gweh-MEH-see-ah

Name means: “named after Martín Miguel de Güemes, an Argentine independence hero”1

Ate: MeatMeat-eating dinosLate Cretaceous

Guemesia was a small, meat-eating dinosaur that lived in what is now Argentina. It is one of the smallest abelisaurids ever found, about the size of a large dog. Its nearly complete braincase helped scientists learn a lot about this little predator.1 2

Lived

84 to 66 million years ago4

Late Cretaceous

Fossils found in

Amblayo Valley, Salta Province, Argentina (Los Blanquitos Formation)1 4

Food

Meat4

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

cool stuff

Fun facts

Guemesia is known from only a single, nearly complete braincase, which is very rare for abelisaurids.1 2

It is one of the smallest abelisaurids ever discovered, much smaller than relatives like Carnotaurus.1 2

Unlike many other abelisaurids, Guemesia had no horns or bumps on its skull.2

Its skull roof was thin, and its parietal eminence was low and narrow, at the same level as the sagittal crest.2

Guemesia lived during the Late Cretaceous period, about 72 million years ago.1

It is the first definitive abelisaurid dinosaur found in northwestern Argentina.2

Guemesia belongs to the group Brachyrostra, which includes many other South American abelisaurids.1

AI-made picture of Guemesia — An AI-made picture of how Guemesia might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.

you asked

Most asked questions about Guemesia

?How big was Guemesia?

About the size of a large dog, making it one of the smallest abelisaurids known.1 3

?Did Guemesia have horns?

No. Unlike many other abelisaurids, Guemesia had no horns or bumps on its skull.1 2

?What did Guemesia eat?

It was a meat-eater, likely feeding on large dinosaurs like titanosaurs, using its powerful head and jaws instead of its tiny arms.3

?When did Guemesia live?

It lived during the Late Cretaceous period, about 72 million years ago, just before the dinosaurs went extinct.1 3

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For dino experts

Scientific name: Guemesia
Named by: Agnolín et al. 20214
Group: Meat-eating dinos
Family / clade: Abelisauridae4
Classification: Theropoda > Ceratosauria > Abelisauridae4
Age of the rocks: 84 to 66 million years (Campanian / Maastrichtian)4
Rock formations: Los Blanquitos4
Countries: Argentina4
Fossil records: 1 in the Paleobiology Database4
Discovery: Guemesia was named in 2022 by paleontologist Federico Agnolín and colleagues. The fossil, a nearly complete braincase, was found in the Los Blanquitos Formation in Salta Province, Argentina.1 2
Still debated: Scientists are not sure exactly how big Guemesia was, because only its braincase has been found. Its small size might mean it was a juvenile or a particularly small species.1 2

Where the facts come from

Guemesia (en.wikipedia.org)
First definitive abelisaurid theropod from the Late Cretaceous of Northwestern Argentina: Journal of Vertebrate Paleontology: Vol 41 , No 4 - Get Access (tandfonline.com)
New armless abelisaur dinosaur species discovered in Argentina | Natural History Museum (nhm.ac.uk)
Guemesia in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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