Huinculsaurus

Huinculsaurus
Temporal range: Early Cretaceous (Albian), 106.2 Ma
Speculative life restoration
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: †Noasauridae
Subfamily: †Elaphrosaurinae
Genus: †Huinculsaurus
Baiano, Coria, & Cau, 2020
Type species
†Huinculsaurus montesi
Baiano, Coria, & Cau, 2020

Huinculsaurus is an extinct genus of noasaurid dinosaurs known from the Early Cretaceous Huincul Formation of Argentina. The genus contains a single species, Huinculsaurus montesi, known from five partial vertebrae.

Discovery and naming

Size compared to a human

The only known fossils of Huinculsaurus was discovered around 1991 in the Huincul Formation, about 10 metres (33 ft) away from where the Ilokelesia holotype was discovered in the Argentine Province of Neuquén. The vertebrae were mechanically separated during preparation before being formally published in 2020.

The genus was named for the Huincul Formation, where it was found, coupled with the latinized Greek suffix "saurus", meaning "lizard". The species epithet was given in honor of Eduardo Montes, a technician and fossil preparator at the Carmen Funes Museum, who helped prepare the specimen and died shortly before its official publication.

Description

The holotype of Huinculsaurus, given the specimen number MCF-PVPH-36, consists of three thoracic and two sacral vertebrae. It is believed to have been an immature individual because the centra are not fully fused to the neural arches. Researchers have estimated that in life, it was around 3.42 metres (11.2 ft) long.

Huinculsaurus is distinguished from all other theropods by several autapomorphic features of the vertebrae including elongated articular facets on the prezygapophyses, pneumatic foramina on the underside of the dorsal vertebrae, and an accessory lamina on the dorsal neural arches.

Classification

In their description of Huinculsaurus, Mattia Baiano and colleagues conducted a phylogenetic analysis using two datasets independently developed by previous authors. In both analyses, Huinculsaurus was found to be a close relative of the Late Jurassic theropod Elaphrosaurus, which lived more than 60 million years earlier. The authors noted that this relationship is tenuous due to the fragmentary nature of the fossils of Huinculsaurus. They remarked that the vertebrae of Huinculsaurus share many similarities with Noasauridae as well as Abelisauridae, which make its precise classification difficult. In their second analysis, they recovered Noasauridae as paraphyletic, which may explain some of the mosaic features of the vertebrae. However, the relative lack of available fossils from small ceratosaurs makes their hypotheses about its evolutionary relationships very preliminary. Abbreviated versions of both analyses conducted by Baiano and colleagues are shown below.

Dataset of Wang et al. (2017)
Ceratosauria
Dataset of Dal Sasso et al. (2018)
Ceratosauria

Paleoecology

Paleoenvironment

Huinculsaurus was discovered Huincul Formation, a subdivision of the Neuquén Group. This unit is located in the Neuquén Basin in Patagonia. The Huincul Formation is composed of yellowish and greenish sandstones of fine-to-medium grain, some of which are tuffaceous. These deposits were laid down during the Lower Cretaceous. Earlier findings suggested a Cenomanian–Turonian age, or possibly an Early Turonian to Late Santonian age. The deposits represent the drainage system of a braided river.

The Huincul Formation is thought to represent an arid environment with ephemeral or seasonal streams. In some areas, it is up to 250 metres (820 ft) thick. It is mainly composed of green and yellow sandstones and can easily be differentiated from the overlying Lisandro Formation, which is red in color. The Candeleros Formation, underlying the Huincul, is composed of darker sediments, making all three formations easily distinguishable.

Fossilised pollen indicates a wide variety of plants were present in the Huincul Formation. A study of the El Zampal section of the formation found hornworts, liverworts, ferns, conifers, and some angiosperms (flowering plants).

Contemporary fauna

Size comparison of some of the fauna of the Huincul Formation

The Huincul Formation is among the richest Patagonian vertebrate associations, preserving fish including lungfish and gar, chelid turtles, squamates, sphenodonts, neosuchian crocodilians, and a wide variety of dinosaurs. Vertebrates are most commonly found in the lower, and therefore older, part of the formation.

Huinculsaurus is known to have coexisted with the abelisaurid Ilokelesia, which was found at the same locality. Many non-avian dinosaurs are known from the Huincul Formation, although it is not known with confidence if all of them directly coexisted with Huinculsaurus. Sauropods are represented by the titanosaurs Bustingorrytitan, Choconsaurus, Chucarosaurus, and Argentinosaurus as well as the rebbachisaurids Astigmasaura, Cathartesaura, Cienciargentina, and Sidersaura. Theropods are also diverse and include the abelisaurids Tralkasaurus and Skorpiovenator, the carcharodontosaurids Mapusaurus, Meraxes, and Taurovenator, the paravian Overoraptor, and the enigmatic theropods Aoniraptor and Gualicho. The elasmarian ornithopod Chakisaurus is the only ornithischian dinosaur named from the formation.

References

  1. ↑ Coria, R.A.; Salgado, L. & Calvo, J.O. (1991) "Primeros restos de dinosaurios Theropoda del Miembro Huincul, Formación Río Limay (Cretácico Tardío Presenoniano), Neuquén, Argentina." Ameghiniana, 28: 405-406.
  2. 1 2 3 4 5 Mattia Baiano; Rodolfo Coria; Andrea Cau (2020). "A new abelisauroid (Dinosauria: Theropoda) from the Huincul formation (lower upper Cretaceous, Neuquén Basin) of Patagonia, Argentina". Cretaceous Research. 110. Bibcode:2020CrRes.11004408B. doi:10.1016/j.cretres.2020.104408. hdl:11336/146978.
  3. ↑ Seculi Pereyra, E. E.; Pérez, D. E.; Méndez, A. H. (2025). "Macroevolutionary trends in Ceratosauria body size: insights of phylogenetic comparative methods". BMC Ecology and Evolution. 25 (1). 32. Bibcode:2025BMCEE..25...32P. doi:10.1186/s12862-025-02374-y. PMC 11994025. PMID 40221646. Refer Table 2, Supplementary data 1
  4. ↑ Leanza, H.A; Apesteguı́a, S.; Novas, F.E; de la Fuente, M.S. (February 1, 2004). "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages". Cretaceous Research. 25 (1): 61–87. Bibcode:2004CrRes..25...61L. doi:10.1016/j.cretres.2003.10.005. ISSN 0195-6671.
  5. ↑ Maniel, Ignacio J.; Almeida, Rafael; Kimbrough, David L.; Susana de la Puente, G.; Garrido, Alberto C.; Bellardini, Flavio; Mahoney, J. Brian (2026-07-30). "Albian zircon U-Pb crystallization ages from tuff beds in the Candeleros and Huincul formations, Neuquén Basin, Argentina". Gondwana Research. doi:10.1016/j.gr.2026.06.020. ISSN 1342-937X.
  6. ↑ Motta, Matías J.; Aranciaga Rolando, Alexis M.; Rozadilla, Sebastián; Agnolín, Federico E.; Chimento, Nicolás R.; Egli, Federico Brissón; Novas, Fernando E. (June 2016). "New theropod fauna from the Upper Cretaceous (Huincul Formation) of northwestern Patagonia, Argentina". New Mexico Museum of Natural History and Science Bulletin. 71: 231–253 – via ResearchGate.
  7. ↑ Corbella, H.; Novas, F.E.; Apesteguía, S.; Leanza, H. (2004). "First fission-track age for the dinosaur-bearing Neuquén Group (Upper Cretaceous), Neuquén Basin, Argentina". Revista del Museo Argentino de Ciencias Naturales. Nueva Serie. 6 (21): 227–232. doi:10.22179/REVMACN.6.84.
  8. ↑ Rainoldi, A.L.; Franchini, Marta; Beaufort, D.; Mozley, P.; Giusiano, A.; Nora, C.; Patrier, P.; Impiccini, A.; Pons, J. (2015). "Mineral reactions associated with hydrocarbon paleomigration in the Huincul High, Neuquén Basin, Argentina". GSA Bulletin. 127 (11–12): 1711–1729. Bibcode:2015GSAB..127.1711R. doi:10.1130/B31201.1. hdl:11336/36686.
  9. ↑ Coria, R.A.; Currie, P.J. (2006). "A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina". Geodiversitas. 28: 71–118. Retrieved 2019-02-16.
  10. ↑ Sánchez, María Lidia; Heredia, Susana; Calvo, Jorge O. (2006). "Paleoambientes sedimentarios del Cretácico Superior de la Formación Plottier (Grupo Neuquén), Departamento Confluencia, Neuquén" [Sedimentary paleoenvironments in the Upper Cretaceous Plottier Formation (Neuquen Group), Confluencia, Neuquén)]. Revista de la Asociación Geológica Argentina. 61: 3–18. Retrieved 2019-02-16.
  11. ↑ Leanza, H.A.; Apesteguia, S.; Novas, F.E.; De la Fuente, M.S. (2004). "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages". Cretaceous Research. 25 (1): 61–87. Bibcode:2004CrRes..25...61L. doi:10.1016/j.cretres.2003.10.005. Retrieved 2019-02-16.
  12. ↑ Vallati, P. (2001). "Middle cretaceous microflora from the Huincul Formation ("Dinosaurian Beds") in the Neuquén Basin, Patagonia, Argentina". Palynology. 25 (1): 179–197. Bibcode:2001Paly...25..179V. doi:10.2113/0250179.
  13. ↑ Motta, M.J.; Aranciaga Rolando, A.M.; Rozadilla, S.; Agnolín, F.E.; Chimento, N.R.; Egli, F.B.; Novas, F.E. (2016). "New theropod fauna from the upper cretaceous (Huincul Formation) of Northwestern Patagonia, Argentina". New Mexico Museum of Natural History and Science Bulletin. 71: 231–253.
  14. ↑ Motta, M.J.; Brissón Egli, F.; Aranciaga Rolando, A.M.; Rozadilla, S.; Gentil, A. R.; Lio, G.; Cerroni, M.; Garcia Marsà, J.; Agnolín, F. L.; D'Angelo, J. S.; Álvarez-Herrera, G. P.; Alsina, C.H.; Novas, F.E. (2019). "New vertebrate remains from the Huincul Formation (Cenomanian–Turonian;Upper Cretaceous) in Río Negro, Argentina". Publicación Electrónica de la Asociación Paleontológica Argentina. 19 (1): R26. doi:10.5710/PEAPA.15.04.2019.295. hdl:11336/161858. S2CID 127726069. Archived from the original on December 14, 2019. Retrieved December 14, 2019.
  15. ↑ Bellardini, F.; Filippi, L.S. (2018). "New evidence of saurischian dinosaurs from the upper member of the Huincul Formation (Cenomanian) of Neuquén Province, Patagonia, Argentina". Reunión de Comunicaciones de la Asociación Paleontológica Argentina: 10.
  16. ↑ Calvo, Jorge Orlando; Valieri, Ruben D. Juarez; Ríos, Sergio D. (2011). "Sauropods crossing formations: Biostratigraphical implications for Patagonian Faunal Assemblages". In Calvo, Jorge O.; Riga, Bernardo Gonzalez; Porfiri, Juan; Dos Santos, Domenica (eds.). Paleontología y Dinosaurios desde América Latina [Paleontology and Dinosaurs from Latin America]. EDIUNC, Universidad Nacional de Cuyo. p. 153-160.
  17. ↑ Salgado, Leonardo (2023). "A new gigantic titanosaur (Dinosauria, Sauropoda) from the early Late Cretaceous of Patagonia (Neuquén Province, Argentina)". Acta Palaeontologica Polonica. 68. doi:10.4202/app.01086.2023.
  18. ↑ Lerzo, Lucas Nicolás; Gallina, Pablo Ariel; Canale, Juan Ignacio; Otero, Alejandro; Carballido, José Luis; Apesteguía, Sebastián; Makovicky, Peter Juraj (2024-01-03). "The last of the oldies: a basal rebbachisaurid (Sauropoda, Diplodocoidea) from the early Late Cretaceous (Cenomanian–Turonian) of Patagonia, Argentina". Historical Biology. 37 (2): 208–233. doi:10.1080/08912963.2023.2297914. ISSN 0891-2963.
  19. ↑ Bellardini, Flavio; Filippi, Leonardo S.; Carballido, Jose L.; Garrido, Alberto C.; Baiano, Mattia A. (2025-06-13). "Side by side with titans: a new rebbachisaurid dinosaur from the Huincul Formation (upper Cenomanian) of Patagonia, Argentina". Cretaceous Research. 176 (in press) 106188. 106188. doi:10.1016/j.cretres.2025.106188. hdl:11336/277518.
  20. ↑ Canale, Juan I.; Apesteguía, Sebastián; Gallina, Pablo A.; Mitchell, Jonathan; Smith, Nathan D.; Cullen, Thomas M.; Shinya, Akiko; Haluza, Alejandro; Gianechini, Federico A.; Makovicky, Peter J. (July 2022). "New giant carnivorous dinosaur reveals convergent evolutionary trends in theropod arm reduction". Current Biology. 32 (14): 3195–3202.e5. doi:10.1016/j.cub.2022.05.057. PMID 35803271. S2CID 250343124.
  21. ↑ Alvarez-Nogueira, Rodrigo; Rozadilla, Sebastián; Agnolín, Federico L.; Garcia Marsà, Jordi A.; Motta, Matias J.; Novas, Fernando E. (2024-03-11). "A new ornithopod from the Upper Cretaceous (Huincul Formation) of Northwestern Patagonia, Argentina. Implications on elasmarian postcranial anatomy". Cretaceous Research. 159 (In press) 105874. Bibcode:2024CrRes.15905874N. doi:10.1016/j.cretres.2024.105874.