Pronunciation: WAH-kin-RAP-tuh
Meaning: Joaquin plunderer
Author/s: Ibiricu et al. (2025)
Synonyms: None known
First Discovery: Chubut Province, Argentina
Discovery Chart Position: #1179
Joaquinraptor casali
Megaraptora is one of the most intriguing—and puzzling—groups of Cretaceous theropods from Gondwana. These dinosaurs belong to the broader tetanuran lineage, and are best known for their long, narrow skulls with low-crowned teeth, bones riddled with air spaces, and, most strikingly, massive forelimbs tipped with oversized claws on the first two fingers, at least in the more derived forms.
Where exactly megaraptorans fit within the theropod family tree is still hotly debated. Some researchers see them as close relatives of the giant carcharodontosaurian allosauroids, while others argue they’re early coelurosaurs—maybe even basal tyrannosauroids. The problem? Most fossils are frustratingly fragmentary, with very few specimens preserving the same bones for direct comparison.
When palaeontologists discovered an unusually complete megaraptoran near Lago Colhué Huapi in central Patagonia, hopes were high that it might finally settle the debate. Alas, the ensuing study focused more on where the new species, Joaquinraptor, sits within Megaraptora and less on whether the group as a whole is closer to T. rex or Allosaurus. Still, the find wasn’t without its revelations: the specimen offered rare clues about megaraptoran diet and feeding behaviour, thanks in no small part to the crocodyliform arm bone wedged between its jaws.
Where exactly megaraptorans fit within the theropod family tree is still hotly debated. Some researchers see them as close relatives of the giant carcharodontosaurian allosauroids, while others argue they’re early coelurosaurs—maybe even basal tyrannosauroids. The problem? Most fossils are frustratingly fragmentary, with very few specimens preserving the same bones for direct comparison.
When palaeontologists discovered an unusually complete megaraptoran near Lago Colhué Huapi in central Patagonia, hopes were high that it might finally settle the debate. Alas, the ensuing study focused more on where the new species, Joaquinraptor, sits within Megaraptora and less on whether the group as a whole is closer to T. rex or Allosaurus. Still, the find wasn’t without its revelations: the specimen offered rare clues about megaraptoran diet and feeding behaviour, thanks in no small part to the crocodyliform arm bone wedged between its jaws.
(Casal's Joaquin Plunderer)Etymology
Joaquinraptor is derived from "Joaquín", in tribute to the son of the first author (Lucio M. Ibiricu) and the informal name given to the locality when the skeleton of the taxon was discovered (Valle Joaquín), and the Latin "raptor" (plunderer, robber, thief).
The species epithet, casali, honours Dr. Gabriel Andrés Casal for his many contributions to knowledge of the Cretaceous palaeontology and geology of central Patagonia (including the formal recognition and naming of the formation from which Joaquinraptor was recovered).
Zoobank registry: urn:lsid:zoobank.org:act:3AA601F2-5DFC-452B-9609-E83C913F8C2D
Discovery
The fossils of Joaquinraptor were found in the Lago Colhué Huapi formation at Valle Joaquín, headwaters of the Río Chico, east of the southeastern shore of Lago Colhué Huapi, Chubut Province, central Patagonia, Argentina, by Bruno N. Alvarez.
The holotype (UNPSJB-PV 1112) is a partially articulated partial skeleton.
Preparator
Marcelo Luna.
