Juvenile specimen of Megaraptor (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation

Porfiri, Juan D.; Novas, Fernando E.; Calvo, Jorge O.; Agnolín, Federico; Ezcurra, Martín D.; Cerda, Ignacio Alejandro

doi:10.1016/j.cretres.2014.04.007

Cited by 85 publications

(154 citation statements)

References 56 publications

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“…After a comprehensive phylogenetic analysis, these authors considered megaraptorans as allosauroids closely related with carcharodontosaurid theropods, an interpretation subsequently followed by later authors (Carrano et al, 2012;Zanno and Makovicky, 2013). However, recent studies conducted by some of us (e.g., Novas et al, 2013;Porfiri et al, 2014) have suggested that megaraptorans are not representative of archaic allosauroid tetanurans, but instead argued that megaraptorans are coelurosaurs, and representatives of a basal tyrannosauroid radiation in particular (Novas et al, 2013). Recent discovery of cranial remains of a juvenile specimen of Megaraptor namunhuaiquii (Porfiri et al, 2014) offered novel anatomical information that supported this phylogenetic interpretation.…”

Section: Introductionmentioning

confidence: 96%

“…2) and Aves, and may suggest a more complex folding system than in basal theropods, a hypothesis that needs to be tested properly. Apart from the similarity with some coelurosaurs described for the distal end, the robust construction of the humerus in Megaraptor and Australovenator is closer to Allosaurus (width:length ratio approximately 40; Madsen, 1976;Hocknull et al, 2009;Porfiri et al, 2014) than the elongate and more gracile humeral proportions of Guanlong and Deinonychus (width:length ratio approximately 30; pers. obs.…”

Section: Comparative Anatomymentioning

confidence: 99%

“…3). However, the recent discovery of a juvenile specimen of M. namunhuaiquii (Porfiri et al, 2014) documents for the first time the humeral morphology in this genus. Although the humerus does not preserve complete proximal and distal ends, it offers reliable information to calculate humeral proportions in this Patagonian taxon.…”

Section: Comparative Anatomymentioning

confidence: 99%

“…The humerus of Megaraptor (Porfiri et al, 2014) and Australovenator (White et al, 2012) resembles basal tetanurans (e.g., Allosaurus, Acrocanthosaurus, Piatnitzkysaurus; Madsen, 1976;Currie and Carpenter, 2000;Bonaparte, 1986) and basal coelurosaurs (e.g., Coelurus, Ornitholestes, Guanlong; Osborn, 1903;Carpenter, 2005;Xu et al, 2006; fig. 1) in being sigmoidshaped in anterior and lateral views, with a prominent deltopectoral crest.…”

Section: Comparative Anatomymentioning

confidence: 99%

“…The best known megaraptorids are Megaraptor namunhuaiquii (Novas, 1998;Calvo et al, 2004;Porfiri et al, 2014), Orkoraptor bukei (Novas et al, 2008), and Aerosteon riocoloradensis (Sereno et al, 2008), coming from different formations of Turonian through Santonian age of Argentina; and Australovenator wintonensis (Hocknull et al, 2009;White et al, 2012White et al, , 2013, from Cenomanian rocks of Australia.…”

Section: Introductionmentioning

confidence: 99%

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Phylogenetic relationships of the Cretaceous Gondwanan theropods Megaraptor and Australovenator: the evidence afforded by their manual anatomy

Novas¹,

Rolando²,

Agnolín³

2016

MMV

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General comparisons of the manual elements of megaraptorid theropods are conducted with the aim to enlarge the morphological dataset of phylogenetically useful features within Tetanurae. Distinctive features of Megaraptor are concentrated along the medial side of the manus, with metacarpal I and its corresponding digit being considerably elongated. Manual ungual of digit I is characteristically enlarged in megaraptorids, but it is also transversely compressed resulting in a sharp ventral edge. We recognize two derived characters shared by megaraptorans and coelurosaurs (i.e., proximal end of metacarpal I without a deep and wide groove continuous with the semilunar carpal, and metacarpals I and II long and slender), and one derived trait similar to derived tyrannosauroids (i.e., metacarpal III length <0.75 length of metacarpal II). However, after comparing carpal, metacarpal and phalangeal morphologies, it becomes evident that megaraptorids retained most of the manual features present in Allosaurus. Moreover, Megaraptor and Australovenator are devoid of several manual features that the basal tyrannosauroid Guanlong shares with more derived coelurosaurs (e.g., Deinonychus), thus countering our own previous hypothesis that Megaraptora is well nested within Tyrannosauroidea.

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Section: Introductionmentioning

confidence: 96%

Section: Comparative Anatomymentioning

confidence: 99%

Section: Comparative Anatomymentioning

confidence: 99%

Section: Comparative Anatomymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phylogenetic relationships of the Cretaceous Gondwanan theropods Megaraptor and Australovenator: the evidence afforded by their manual anatomy

Novas¹,

Rolando²,

Agnolín³

2016

MMV

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Skull Anatomy and Pneumaticity of the Enigmatic Coelurosaurian Theropod Bicentenaria argentina.

Rolando

Cerroni

Novas

2019

The Anatomical Record

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The enigmatic basal coelurosaur Bicentenaria argentina is a small theropod that comes from the Upper Cretaceous of Patagonia. It is constituted by more than 130 elements, including cranial remains. These are represented by an incomplete snout, palate, dermatocranium, and lower jaws still in articulation. The skull material of Bicentenaria was preliminarily studied by previous authors. In this study, we conducted a CT scan of the holotype of Bicentenaria, which allowed us to fully describe all preserved skull bones, including some previously unknown elements. The morphological analysis indicates that Bicentenaria shares many cranial features with other basal coelurosaurs as compsognathids, Ornitholestes, and tyrannosauroids. Otherwise, results of this analysis show that Bicentenaria exhibits a set of traits unique to this taxon. Furthermore, several pneumatic recesses were closely matched with those pneumatic features present in many derived coelurosaurs, particularly tyrannosauroids. This new information, together with future discoveries, will improve our knowledge about the muscular correlates of Bicentenaria and other coelurosaurs, and may shed light about the phylogenetic relationships of this group. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1884–1900, 2020. © 2019 American Association for Anatomy

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Reconstruction of the pectoral girdle and forelimb musculature of Megaraptora (Dinosauria: Theropoda)

Rolando

Novas

Calvo

et al. 2023

The Anatomical Record

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Megaraptora is a group of enigmatic, carnivorous non‐avian theropod dinosaurs from the Cretaceous of Asia, Australia, and especially South America. Perhaps the most striking aspect of megaraptoran morphology is the large, robustly constructed forelimb that, in derived members of the clade, terminates in a greatly enlarged manus with hypertrophied, raptorial unguals on the medialmost two digits and a substantially smaller ungual on digit III. The unique forelimb anatomy of megaraptorans was presumably associated with distinctive functional specializations; nevertheless, its paleobiological significance has not been extensively explored. Here we draw from observations of the pectoral girdle and forelimb skeletons of Megaraptora and myological assessments of other archosaurian taxa to provide a comprehensive reconstruction of the musculature of this anatomical region in these singular theropods. Many muscle attachment sites on megaraptoran forelimb bones are remarkably well developed, which in turn suggests that the muscles themselves were functionally significant and important to the paleobiology of these theropods. Furthermore, many of these attachments became increasingly pronounced through megaraptoran evolutionary history, being substantially better developed in derived taxa such as Australovenator wintonensis and especially Megaraptor namunhuaiquii than in early branching forms such as Fukuiraptor kitadaniensis. When considered alongside previous range of motion hypotheses for Australovenator, our results indicate that megaraptorans possessed a morphologically and functionally specialized forelimb that was capable of complex movements. Notable among these were extensive extension and flexion, particularly in the highly derived manus, as well as enhanced humeral protraction, attributes that very probably aided in prey capture.

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Juvenile specimen of Megaraptor (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation

Cited by 85 publications

References 56 publications

Phylogenetic relationships of the Cretaceous Gondwanan theropods Megaraptor and Australovenator: the evidence afforded by their manual anatomy

Phylogenetic relationships of the Cretaceous Gondwanan theropods Megaraptor and Australovenator: the evidence afforded by their manual anatomy

Skull Anatomy and Pneumaticity of the Enigmatic Coelurosaurian Theropod Bicentenaria argentina.

Reconstruction of the pectoral girdle and forelimb musculature of Megaraptora (Dinosauria: Theropoda)

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