Open Paleo

Joaquinraptor

Ibiricu et al., 2025 wah-KEEN-rap-tor

Named after San Joaquín, a locality in Chubut Province, Argentina, near where the fossils were found, combined with Latin raptor (thief); meaning 'Joaquín thief'

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Joaquinraptor is an extinct genus of megaraptorid theropod dinosaurs known from the Late Cretaceous Lago Colhué Huapi Formation of Argentina. The genus contains a single species, Joaquinraptor casali, representing the youngest (most recent) definitive megaraptoran. It is known from a partially articulated, incomplete skeleton including vertebrae and bones of the skull, forelimbs and hindlimbs, and pectoral girdle, making it one of the most completely known members of the Megaraptora. It was likely at least 7 meters (23 ft) long.

Diagnosis

  1. Parietals strongly compressed transversely, narrower than frontals
  2. Anterior margin of supratemporal fossa with sigmoid contour
  3. Middle or posterior caudal vertebral centra with well-marked elliptical lateral fossae occupying more than half lateral surfaces
  4. Humerus with subrectangular deltopectoral crest
  5. Ulna with proximodistally enlarged olecranon process
  6. Distal end of radius crescent-shaped

Species

Joaquinraptor casali Ibiricu et al., 2025

Type species

Named for Gabriel Andrés Casal, the researcher who first described the Lago Colhué Huapi Formation and made significant contributions to Patagonian paleontological and geological research.

Holotype
UNPSJB-PV 1112 , Universidad Nacional de la Patagonia San Juan Bosco
Material
Partially articulated partial skeleton including mostly disarticulated partial skull, postcranial axial elements, and appendicular elements.
Horizon
upper Lago Colhué Huapi Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Valle Joaquín, Chubut, Argentina

References

  1. Ibiricu, L. M.; Lamanna, M. C.; Álvarez, B. N.; Cerda, I. A.; Caglianone, J. L.; Cardozo, N. V.; Luna, M.; Martínez, R. D. (2025). Latest Cretaceous megaraptorid theropod dinosaur sheds light on megaraptoran evolution and palaeobiology. Nature Communications 16(1). Springer Science and Business Media LLC. doi:10.1038/s41467-025-63793-5 ibiricu2025a