Pronunciation: gweh-MAY-see-uh
Meaning: for Güemes
Author/s: Agnolín et al. (2022)
Synonyms: None known
First Discovery: Salta, Argentina
Discovery Chart Position: #1058
Guemesia ochoai
The fossil record of abelisaurid theropods in South America is limited mostly to Brazil and Argentina, particularly Argentine Patagonia, where their record is relatively abundant and includes well-known and complete specimens. However, for northwestern Argentina, abelisaurids have long been represented only by incomplete and isolated bones and teeth—many of which remain unpublished or enigmatic. That changed, slightly, in 2022, when Guemesia ochoai from the Los Blanquitos Formation of NW Argentina was named and described by Fed Agnolín et al. And while its fossils are not great, at least they are fossils, and thus tangible echoes of a life once lived.
Guemesia is known solely from a braincase—nearly complete, but still just one part of the skull. And yet, even this modest relic speaks volumes. It bears peculiar features, such as slender frontal bones (part of the skull roof) with internal cavities that hint at vascular (blood transportation) or pneumatic (air-filled) structures, but lacks the hallmark traits typical of thick-skulled abelisaurids, including ornamentation like horns, bulges, or rough, knobbly surface textures. Compared to its more famous kin, Abelisaurus and Carnotaurus, Guemesia is small in stature and may represent either a juvenile or a diminutive lineage. Its true scale is still cloaked in uncertainty.
And so, from the dust of Saltas' ancient rocks,
A braincase, alone, now softly talks.
It whispers of deserts, of heat and of bone,
Of creatures that hunted and wandered alone.
No horns to boast, no jaws to roar,
Just quiet clues from a cranial core.
Guemesia, a ghost of a vanished land,
Now speaks through stone and scholar’s hand.
Guemesia is known solely from a braincase—nearly complete, but still just one part of the skull. And yet, even this modest relic speaks volumes. It bears peculiar features, such as slender frontal bones (part of the skull roof) with internal cavities that hint at vascular (blood transportation) or pneumatic (air-filled) structures, but lacks the hallmark traits typical of thick-skulled abelisaurids, including ornamentation like horns, bulges, or rough, knobbly surface textures. Compared to its more famous kin, Abelisaurus and Carnotaurus, Guemesia is small in stature and may represent either a juvenile or a diminutive lineage. Its true scale is still cloaked in uncertainty.
And so, from the dust of Saltas' ancient rocks,
A braincase, alone, now softly talks.
It whispers of deserts, of heat and of bone,
Of creatures that hunted and wandered alone.
No horns to boast, no jaws to roar,
Just quiet clues from a cranial core.
Guemesia, a ghost of a vanished land,
Now speaks through stone and scholar’s hand.
(for Güemes and Ochoa)Etymology
Guemesia honours Martín Miguel de Güemes, a military leader who defended northwestern Argentina from the Spanish royalist army during the Argentine War of Independence. The year 2021 was declared as "the bicentenary of the death of General Güemes" by the Senate of the Argentine
Nation.
The species epithet, ochoai, honours Javier Ochoa, a technician of the Museo Regional "Florentino Ameghino", Río Tercero city (Córdoba province, Argentina) who has worked extensively in Cretaceous outcrops of Northwestern Argentina and discovered the holotype specimen.
Discovery
The remains of Guemesia were discovered in the Los Blanquitos Formation (Salta Group) in the south part of the Amblayo valley, close to Amblayo town, Salta Province, Argentina, by Javier Ochoa.
The holotype (IBIGEO-P 103) is a small, nearly complete braincase.
