Patagopelta (meaning "Patagonian shield") is an extinct genus of ankylosaurian dinosaur from the Late Cretaceous (upper Campanian–lower Maastrichtian) Allen Formation of Argentina. The genus contains a single species, P. cristata, known from a partial skeleton. While originally described as a nodosaurine, later discoveries provided support for parankylosaurian affinities for the taxon. Patagopelta is a very small ankylosaur, comparable in size to the dwarf nodosaurid Struthiosaurus, about 2 m (6.6 ft) long.
| Patagopelta Temporal range: Late Cretaceous
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| Skeletal reconstruction showing known osteoderms (top) and other skeletal remains (bottom) in white | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | †Ornithischia |
| Clade: | †Thyreophora |
| Clade: | †Ankylosauria |
| Clade: | †Parankylosauria (?) |
| Genus: | †Patagopelta Riguetti et al., 2022 |
| Species: | †P. cristata
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| Binomial name | |
| †Patagopelta cristata Riguetti et al., 2022
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Discovery and naming
editThe Patagopelta fossil material was found in sediments of the Allen Formation (Salitral Moreno locality) near General Roca, Río Negro Province, Argentina. This locality is dated to the upper Campanian to lower Maastrichtian ages of the Late Cretaceous period. The first remains were described in 1996 and often appeared in the literature as the "Argentinian ankylosaur".[1][2] The fossil material consists of various osteoderms, a tooth, dorsal and caudal vertebrae, and femora. The Patagopelta holotype specimen, MPCA-SM-78, is represented by a cervical half-ring element.[3]
New remains described in 2022 allowed Patagopelta cristata to be described as a new genus and species of nodosaurine dinosaurs by Facundo Riguetti, Xabier Pereda-Suberbiola, Denis Ponce, Leonardo Salgado, Sebastián Apesteguía, Sebastián Rozadilla, and Victoria Arbour. The generic name, "Patagopelta", is derived from "Patago", a reference to the discovery of the taxon in Argentinian Patagonia, and the Greek word "pelta", meaning "shield". The specific name, "cristata", means "crested" in Latin, referring to the large crests on its cervical osteoderms and femur.[3]
Classification
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In their phylogenetic analyses, Riguetti et al. (2022) recovered Patagopelta as a member of the Nodosaurinae, within a clade of entirely North American nodosaurids from the middle of the Cretaceous period, in contrast to previous analyses that recovered it in the Panoplosaurini.[4] In either case, these results would suggest that nodosaurids were part of a migration event of North American fauna into South America. The cladogram below displays the results of their phylogenetic analyses.[3]
| Nodosauridae |
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A study published in 2024 by Agnolín and colleagues reviewed vertebrate fossils from the Cerro Fortaleza Formation and similar Patagonian formations. They mentioned new findings that suggest that Patagopelta may actually represent a parankylosaurian, similar to ankylosaurs like Antarctopelta rather than nodosaurids.[5] In their 2024 redescription of Antarctopelta, Soto Acuña, Vargas & Kaluza further elaborated on this, explaining that the discovery of additional fossil material allowed for a rescoring of its characters in their phylogenetic matrix. Based on these updates, they recovered Patagopelta within the Parankylosauria, along with other Cretaceous Gondwanan ankylosaurs. Their results are displayed in the cladogram below:[6]
| Ankylosauria |
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Paleoecology
editPatagopelta is known from the Late Cretaceous Allen Formation of Río Negro Province, Argentina. Many other dinosaurs, including titanosaurs (Aeolosaurus, Bonatitan, Menucocelsior, Panamericansaurus, Pellegrinisaurus, and Rocasaurus), hadrosaurids (Bonapartesaurus, Kelumapusaura, and Lapampasaurus), abelisaurids (Niebla and Quilmesaurus), dromaeosaurids (Austroraptor), and alvarezsaurids (Bonapartenykus), have been named from the formation. Birds (Lamarqueavis and Limenavis), pterosaurs (Aerotitan), rhynchocephalians (Lamarquesaurus), plesiosaurs (Kawanectes), and dryolestoid and gondwanathere mammals have also been described from the formation.[3][7][8]
References
edit- ^ Rivera-Sylva, H.E.; Frey, E.; Stinnesbeck, W.; Carbot-Chanona, G.; Sanchez-Uribe, I.E.; Guzmán-Gutiérrez, J.R. (2018). "Paleodiversity of Late Cretaceous Ankylosauria from Mexico and their phylogenetic significance". Swiss Journal of Palaeontology. 137 (1): 83–93. Bibcode:2018SwJP..137...83R. doi:10.1007/s13358-018-0153-1. ISSN 1664-2376. S2CID 134924657.
- ^ Frauenfelder, Timothy G.; Bell, Phil R.; Brougham, Tom; Bevitt, Joseph J.; Bicknell, Russell D. C.; Kear, Benjamin P.; Wroe, Stephen; Campione, Nicolás E. (2022-03-28). "New Ankylosaurian Cranial Remains From the Lower Cretaceous (Upper Albian) Toolebuc Formation of Queensland, Australia". Frontiers in Earth Science. 10. doi:10.3389/feart.2022.803505. ISSN 2296-6463.
- ^ a b c d Riguetti, Facundo; Pereda-Suberbiola, Xabier; Ponce, Denis; Salgado, Leonardo; Apesteguía, Sebastián; Rozadilla, Sebastián; Arbour, Victoria (2022-12-31). "A new small-bodied ankylosaurian dinosaur from the Upper Cretaceous of North Patagonia (Río Negro Province, Argentina)". Journal of Systematic Palaeontology. 20 (1): 2137441. Bibcode:2022JSPal..2037441R. doi:10.1080/14772019.2022.2137441. ISSN 1477-2019. S2CID 254212751.
- ^ Madzia, D.; Arbour, V.M.; Boyd, C.A.; Farke, A.A.; Cruzado-Caballero, P.; Evans, D.C. (2021). "The phylogenetic nomenclature of ornithischian dinosaurs". PeerJ. 9: e12362. doi:10.7717/peerj.12362. PMC 8667728. PMID 34966571.
- ^ Agnolín, Federico L.; Álvarez Herrera, Gerardo; Rolando, Mauro Aranciaga; Motta, Matías; Rozadilla, Sebastián; Verdiquio, Lucía; D'Angelo, Julia S.; Moyano-Paz, Damián; Varela, Augusto N.; Sterli, Juliana; Bogan, Sergio; Miner, Santiago; Moreno Rodríguez, Ana; Muñoz, Gonzalo; Isasi, Marcelo P.; Novas, Fernando E. (2024). "Fossil vertebrates from the Cerro Fortaleza Formation (Upper Cretaceous), Santa Cruz Province, Argentina". Cretaceous Research. 154. 105735. Bibcode:2024CrRes.15405735A. doi:10.1016/j.cretres.2023.105735.
- ^ Soto Acuña, Sergio; Vargas, Alexander O.; Kaluza, Jonatan (2024). "A new look at the first dinosaur discovered in Antarctica: reappraisal of Antarctopelta oliveroi (Ankylosauria: Parankylosauria)". Advances in Polar Science. 35 (1): 78–107. doi:10.12429/j.advps.2023.0036.
- ^ Aranciaga Rolando, Mauro; Cerroni, Mauricio A.; Garcia Marsà, Jordi A.; Agnolín, Federico l.; Motta, Matías J.; Rozadilla, Sebastián; Brisson Eglí, Federico; Novas, Fernando E. (2020-10-14). "A new medium-sized abelisaurid (Theropoda, Dinosauria) from the late cretaceous (Maastrichtian) Allen Formation of Northern Patagonia, Argentina". Journal of South American Earth Sciences. 105: 102915. doi:10.1016/j.jsames.2020.102915. hdl:11336/150468. ISSN 0895-9811. S2CID 225123133.
- ^ Rozadilla, Sebastián; Brissón-Egli, Federico; Lisandro Agnolín, Federico; Aranciaga-Rolando, Alexis Mauro; Novas, Fernando Emilio (2022). "A new hadrosaurid (Dinosauria: Ornithischia) from the Late Cretaceous of northern Patagonia and the radiation of South American hadrosaurids". Journal of Systematic Palaeontology. 19 (17): 1207–1235. doi:10.1080/14772019.2021.2020917. S2CID 247122005.