Open Paleo

Gualicho

Apesteguía et al., 2016 gwah-LEE-cho

Named in reference to the gualichu, a malevolent supernatural entity in the mythology of the Mapuche and other Patagonian peoples

100.5–89.8 million years ago Cenomanian–Turonian, Late Cretaceous
Late Cretaceous stages

Gualicho is an enigmatic genus of theropod dinosaurs. The type species is Gualicho shinyae. It lived in what is now northern Patagonia, on what was then a South American island continent split off from the supercontinent Gondwana. The fossils were found in the Huincul Formation, dating to the late Cenomanian-early Turonian age of the upper Cretaceous Period, around 91 million years ago.

Under dispute

The position of Gualicho shinyae is highly unstable. Apesteguía and colleagues (2016) recovered it as a neovenatorid carcharodontosaurian (an allosauroid) sister to Deltadromeus, arguing its tyrannosaurid-like didactyl manus is convergent rather than evidence of tyrannosauroid affinity, and noted a mosaic of ceratosaurian and tetanuran characters; other analyses instead place it within Coelurosauria (Porfiri and colleagues, 2018) or as an early-branching ornithomimosaur alongside Deltadromeus (Delcourt and colleagues, 2025). Because these hypotheses span Allosauroidea and Coelurosauria, it is placed conservatively at Avetheropoda incertae sedis.

Diagnosis

  1. Posterior dorsal vertebrae very elongated with slit-like pneumatic openings
  2. Scapular blade narrow with sinuous rostral margin marked by a shallow notch between the acromion process and blade
  3. First and second metacarpals co-ossified proximally; third metacarpal reduced to a splint; forelimb functionally didactyl
  4. Pubes with little or no pubic apron and blade-like boot
  5. Fibula with large fossa and accessory flange on proximocaudal corner, and ridge-like m. iliofibularis tubercle
  6. Third metatarsal with expanded proximal articulation with posterior edge wider than rostral edge (antarctometatarsal condition)

Species

Gualicho shinyae Apesteguía et al., 2016

Type species

Named for Akiko Shinya, preparator at the Field Museum of Natural History, who discovered the holotype skeleton in 2007.

Holotype
MPCN PV 0001 , Museo Patagónico de Ciencias Naturales
Material
Four articulated dorsal vertebral centra, articulated gastral basket, distal tail section, left scapulocoracoid and forelimb, distal ends of both pubes with pubic boot, and parts of both hind limbs
Horizon
lower Huincul Formation, Cenomanian–Turonian, Late Cretaceous , 100.5–89.8 million years ago
Locality
Pueblo Blanco Natural Reserve, Río Negro, Argentina Apesteguía and colleagues (2016) place the holotype on the northern flank of the Meseta de la Rentería and withhold the exact site, holding it on file; Cerroni and colleagues (2020) give Gualicho as described from the Violante farm, whose position they print.

Synonyms of the genus

Name Type Reason
Nototyrannus nomen nudum Informal name; never met ICZN requirements for formal publication and is treated as referable to Gualicho. Per Olshevsky's Dinosaur Genera List.

References

  1. Apesteguía, S.; Smith, N. D.; Juárez Valieri, R. D.; Makovicky, P. J. (2016). An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina. PLOS ONE 11(7): e0157793. Public Library of Science (PLoS). doi:10.1371/journal.pone.0157793

    Describing paper; recovered Gualicho as a neovenatorid allosauroid, sister to Deltadromeus, interpreting its didactyl manus as convergent.

    apesteguía2016a
  2. Porfiri, J. D.; Juárez Valieri, R. D.; Santos, D. D. D.; Lamanna, M. C. (2018). A new megaraptoran theropod dinosaur from the Upper Cretaceous Bajo de la Carpa Formation of northwestern Patagonia. Cretaceous Research 89: 302-319. Elsevier BV. doi:10.1016/j.cretres.2018.03.014

    Recovered Gualicho within Coelurosauria, in a basal polytomy with Chilantaisaurus and Megaraptora.

    porfiri2018a
  3. Delcourt, D.; Grillo, O. N.; Hendrickx, C.; Kellermann, M.; Langer, M. C. (2025). The coelurosaur theropods of the Romualdo formation, early Cretaceous (Aptian) of Brazil: Santanaraptor placidus meets Mirischia asymmetrica. The Anatomical Record ar.70085. Wiley. doi:10.1002/ar.70085

    New matrix recovers Gualicho as an early-branching ornithomimosaur alongside Deltadromeus

    delcourt2025a
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Reports the allosauroid and coelurosaur placements.

    jones2026c
  5. Cerroni, M. A.; Motta, M. J.; Agnolín, F. L.; Aranciaga Rolando, A. M.; Brissón Egli, F.; Novas, F. E. (2020). A new abelisaurid from the Huincul Formation (Cenomanian-Turonian; Upper Cretaceous) of Río Negro province, Argentina. Journal of South American Earth Sciences 98. Elsevier BV. doi:10.1016/j.jsames.2019.102445

    Publishes the type locality coordinate the describing paper withholds.

    cerroni2020a