New records of Theropoda from a Late Cretaceous (Campanian-Maastrichtian) locality in the Magallanes-Austral Basin, Patagonia, and insights into end Cretaceous theropod diversity

Davis, Sarah N.; Soto‐Acuña, Sergio; Fernández, Roy A.; Amudeo-Plaza, Jared; Leppe, Marcelo A.; Rubilar-Rogers, David; Vargas, Alexander O.; Clarke, Julia A.

doi:10.1016/j.jsames.2022.104163

“…So far, and as previously noted in the literature, megaraptoridsynapomorphies are limited but are highly diagnostic [17,41]. In the speci c context of this study, two out of three analyses suggest that Morphotype 1 lacks strong a nities with the Megaraptoridae subclade.…”

Section: Cladistics and Multivariate Analysessupporting

confidence: 79%

Shed teeth from Portezuelo Formation at Sierra del Portezuelo reveal a higher diversity of predator theropods during Turonian-Coniacian times in northern Patagonia

Meso,

Gianechini,

Gomez

et al. 2024

Preprint

0

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The study of thirty-two shed crowns from the Portezuelo Formation (middle Turonian-late Coniacian) at the Sierra del Portezuelo locality, reveals six distinct tooth morphotypes identified through cladistic, discriminant, and cluster analyses. Two morphotypes were identified as belonging to Megaraptoridae, three to Abelisauridae, one to Abelisauroidea, and one to Alvarezsauridae. Additionally, two of the morphotypes exhibit a combination of dental features typically found in megaraptorid and abelisauridtheropods. These results suggest a greater diversity of theropods in the original ecosystem than previously thought, including the presence of a second morphotype of megaraptorid and alvarezsaurid previously undocumented in this formation. Furthermore, the existence of Morphotype 6 indicates the potential coexistence of medium-sized abelisauroids alongside larger abelisaurids in the same ecosystem. These findings underscore the importance of future expeditions to the Sierra del Portezuelo locality to further our understanding of these previously unknown theropod species.

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“…So far, and as previously noted in the literature, megaraptorid synapomorphies are limited but are highly diagnostic [19,44]. In the specific context of this study, two out of three analyses suggest that Morphotype 1 lacks strong affinities with the Megaraptoridae subclade.…”

Section: Cladistics and Multivariate Analysessupporting

confidence: 77%

Shed teeth from Portezuelo formation at Sierra del Portezuelo reveal a higher diversity of predator theropods during Turonian-Coniacian times in northern Patagonia

Meso,

Gianechini,

Gomez

et al. 2024

BMC Ecol Evo

0

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The study of thirty-two shed crowns from the Portezuelo Formation (middle Turonian-late Coniacian) at the Sierra del Portezuelo locality, reveals six distinct tooth morphotypes identified through cladistic, discriminant, and cluster analyses. Two morphotypes were identified as belonging to Megaraptoridae, three to Abelisauridae, one to Abelisauroidea, and one to Alvarezsauridae. Additionally, two of the morphotypes exhibit a combination of dental features typically found in megaraptorid and abelisauridtheropods. These results suggest a greater diversity of theropods in the original ecosystem than previously thought, including the presence of a second morphotype of megaraptorid and alvarezsaurid previously undocumented in this formation. Furthermore, the existence of Morphotype 6 indicates the potential coexistence of medium-sized abelisauroids alongside larger abelisaurids in the same ecosystem. These findings underscore the importance of future expeditions to the Sierra del Portezuelo locality to further our understanding of these previously unknown theropod species.

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“…Late Cretaceous faunas from Indomadagascar are better documented, where the absence of duck-billed dinosaurs is more compelling in suggesting these may have never arrived into particularly isolated regions of Gondwana. Additional discoveries from underexplored regions in the global south will continue to uncover important information on the similarities and differences among pre-extinction ecosystems of the world and whether they can be related to patterns of extinction upon the K-Pg asteroid impact ( 73 ).…”

Section: Discussionmentioning

confidence: 99%

“…The Dorotea Formation mainly comprises greenish gray and reddish brown sandstones with abundant conglomerate and siltstone lenses, thin beds of sandy calcareous concretions, and mudstones of 900 to 1200 m thickness ( 79 ). Along the succession, there are fossil-bearing levels with bivalves, ammonites, gastropods, sharks, plesiosaurs, mosasaurs, frogs, turtles, dinosaurs, mammals, fossil wood, and leaves ( 22 , 66 , 73 , 79 , 80 ).…”

Section: Methodsmentioning

confidence: 99%

Relict duck-billed dinosaurs survived into the last age of the dinosaurs in subantarctic Chile

Alarcón-Muñoz

¹

,

Vargas

²

,

Püschel

³

et al. 2023

Sci. Adv.

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In the dusk of the Mesozoic, advanced duck-billed dinosaurs (Hadrosauridae) were so successful that they likely outcompeted other herbivores, contributing to declines in dinosaur diversity. From Laurasia, hadrosaurids dispersed widely, colonizing Africa, South America, and, allegedly, Antarctica. Here, we present the first species of a duck-billed dinosaur from a subantarctic region, Gonkoken nanoi , of early Maastrichtian age in Magallanes, Chile. Unlike duckbills further north in Patagonia, Gonkoken descends from North American forms diverging shortly before the origin of Hadrosauridae. However, at the time, non-hadrosaurids in North America had become replaced by hadrosaurids. We propose that the ancestors of Gonkoken arrived earlier in South America and reached further south, into regions where hadrosaurids never arrived: All alleged subantarctic and Antarctic remains of hadrosaurids could belong to non-hadrosaurid duckbills like Gonkoken . Dinosaur faunas of the world underwent qualitatively different changes before the Cretaceous-Paleogene asteroid impact, which should be considered when discussing their possible vulnerability.

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New records of Theropoda from a Late Cretaceous (Campanian-Maastrichtian) locality in the Magallanes-Austral Basin, Patagonia, and insights into end Cretaceous theropod diversity

Cited by 7 publications

References 103 publications

Shed teeth from Portezuelo Formation at Sierra del Portezuelo reveal a higher diversity of predator theropods during Turonian-Coniacian times in northern Patagonia

Shed teeth from Portezuelo Formation at Sierra del Portezuelo reveal a higher diversity of predator theropods during Turonian-Coniacian times in northern Patagonia

Shed teeth from Portezuelo formation at Sierra del Portezuelo reveal a higher diversity of predator theropods during Turonian-Coniacian times in northern Patagonia

Relict duck-billed dinosaurs survived into the last age of the dinosaurs in subantarctic Chile

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