Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs

Cau, Andrea; Beyrand, Vincent; Voeten, Dennis F. A. E.; Fernández, Vincent; Tafforeau, Paul; Stein, Koen; Барсболд, Ринчен; Tsogtbaatar, Khishigjav; Currie, Philip J.; Godefroit, Pascal

doi:10.1038/nature24679

Cited by 121 publications

(335 citation statements)

References 24 publications

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“…The distribution of apomorphic dental character states was visualized on a fully topologically constrained tree (sensu Hendrickx et al 2020) using WinClada 1.00.08 (Nixon 2002) on the basis of a Nexus file, with the data matrix and the phylogenetic tree, both created with Mesquite 3.2 (Maddison and Maddison 2017). The tree topology is congruent with the results recovered by Müller et al (2018), fifth phylogenetic analysis (which uses the data matrix of Langer et al 2017) for non-neotheropod saurischians, Ezcurra (2017) for non-averostran neotheropods, Rauhut and Carrano (2016) and Wang et al (2017) for Ceratosauria, Carrano et al (2012) and Rauhut et al (2012 for noncoelurosaurian tetanurans, Brusatte and Carr (2016) for Tyranno-sauroidea, and Cau et al (2017) on the basis of the data set of Brusatte et al (2014) for neocoelurosaurs (i.e., Compsognathidae + Maniraptoriformes; sensu Hendrickx et al 2019).…”

Section: Cladistic and Multivariate Analysessupporting

confidence: 70%

Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China

et al. 2020

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The dental morphology of the holotype of the theropod Sinraptor dongi from the Jurassic Shishugou Formation of China is comprehensively described. We highlight a combination of dental features that appear to be restricted to Sinraptor: (i) crowns with denticulated mesial and distal carinae extending from the root and an irregular surface texture on the enamel; (ii) a D-to salinon-shaped cross-sectional outline at the crown base in mesialmost teeth; (iii) mesial crowns with mesial carinae spiraling mesiolingually and lingually positioned longitudinal groove adjacent to the mesial carina; and (iv) particularly labiolingually compressed lateral teeth with weakly labially deflected distal carinae, flat to concave basocentral surfaces of the labial margins of the crowns, and horizontally elongated distal denticles showing short to well-developed interdenticular sulci. Using cladistic, multivariate, discriminant, and cluster analyses, we demonstrate that the dentition of Sinraptor is relatively similar to that of ceratosaurids, megalosauroids, and other allosauroids and is particularly close to that of Allosaurus. The dental anatomy of Sinraptor and Allosaurus, which differs mainly in the labiolingual compression of the lateral crowns and in the number of premaxillary teeth, shows adaptations towards a predatory lifestyle, including premaxillary teeth capable of enduring tooth-tobone contact and crowns with widely separated mesial and distal carinae capable of inflicting widely open wounds.Résumé : La morphologie dentaire de l'holotype du théropode Sinraptor dongi de la Formation jurassique de Shishugou, en Chine, est décrite de manière exhaustive. Nous soulignons une combinaison de caractères dentaires qui semblent être exclusifs à Sinraptor, dont (i) des couronnes présentant des carènes mésiales et distales s'étendant jusqu'à la racine, et une texture de l'émail irrégulière, (ii) une section transversale de la base de la couronne des dents les plus mésiales en forme de D ou de salinon, (iii) des carènes mésiales des couronnes mésiales spiralant mésiolingualement et un sillon longitudinal adjacent à la carène mésiale sur la surface linguale et (iv) des dents latérales particulièrement comprimées labiolingualement présentant des carènes distales faiblement déviées labialement, des surfaces basocentrales plates à concaves des marges labiales des couronnes et des denticules distaux allongés horizontalement montrant des sulcus interdenticulaires courts à bien développés. En utilisant des analyses cladistiques, multivariées, discriminantes et typologiques, nous démontrons que la dentition de Sinraptor est assez semblable à celle des cératosauridés, des mégalosauroïdes et d'autres allosauroïdes, et est particulièrement proche de celle d'Allosaurus. L'anatomie dentaire de Sinraptor et d'Allosaurus, dont la principale différence est la compression labiolinguale des couronnes latérales et le nombre de dents prémaxillaires, présente des adaptations à un mode de vie prédateur, dont des dents prémaxillaires résistantes aux contac...

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Section: Cladistic and Multivariate Analysessupporting

confidence: 70%

Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China

et al. 2020

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“…Theropod claw sheaths are rare but not unknown from the fossil record [24][25][26][27][28][29][30][31][32][33] . However, for most fossil specimens, the claw sheath is either broken or entirely absent leaving only the ungual bone, and fossilised toe pads or skin are even rarer [34][35][36][37][38][39][40][41][42][43] . Measurements of fossil claw angle tend to be either based on reconstructions 4 or are taken directly on ungual bones 5 in past analyses.…”

Section: Introductionmentioning

confidence: 99%

Inferring lifestyle for Aves and Theropoda: a model based on curvatures of extant avian ungual bones

Cobb

Sellers

2019

Preprint

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Claws are involved in a number of behaviours including locomotion and prey capture, and as a result animals evolve claw morphologies that enable these functions. Past authors have found geometry of the keratinous sheath of the claw to correlate with mode of life for extant birds and squamates; this relationship has frequently been cited to infer lifestyles for Mesozoic theropods including Archaeopteryx. However, claw sheaths rarely fossilise and are prone to deformation; past inferences are thus compromised. As the ungual phalanx within the claw is relatively resistant to deformation and more commonly preserved in the fossil record, geometry of this bone would provide a more useful metric for paleontological analysis. In this study, ungual bones of 108 birds and 5 squamates were imaged using X-ray techniques and a relationship was found between curvatures of the ungual bone within the claw of pedal digit III and four modes of life; ground-dwelling, perching, predatory, and scansorial; using linear discriminant analysis with Kappa equal to 0.69. Our model predicts arboreal lifestyles for certain key taxa Archaeopteryx and Microraptor and a predatory ecology for Confuciusornis. These findings demonstrate the utility of our model in answering questions of palaeoecology, the theropod-bird transition, and the evolution of avian flight. 2/30

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“…Even at similar sizes the divergence between relative hindlimb versus distal limb metrics is clearly illustrated by comparing the Yixian biota contemporaries Changyuraptor and Sinosauropteyrx, both of which are suspected small carnivores that differ in length by 10mm (~ 2% total SVL). Changyuanraptor show a relative hindlimb index of 0.96, which is significantly higher than that is seen in Sinosauropteyrx Interestingly, amongst anchiornithids (a clade of small bodied paravians who have recently suggested to be more closely related to birds than either dromaeosaurids or troodontids [47,48]) we see a diverse pattern of values ranging from Anchiornis at the high end (92-95%) to Caihong (78%) at the lower end, though the latter is still similar to what is seen in the cursorial oviraptorosaur Caudipteryx (0.75-0.79). We calculated maximum speed potential with the larger hindlimb indices in many microraptorines allowing them to achieve higher top end speed suggesting a sharp demarcation between burst speed potential between microraptorines, contemporaneous small bodied compsognathids and basal birds (Figure 2, Sup.…”

Section: Relative Leg Lengthmentioning

confidence: 90%

The fast and the frugal: Divergent locomotory strategies drive limb lengthening in theropod dinosaurs

Dececchi¹,

Mloszewska²,

Holtz³

et al. 2019

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AbstractLimb length, cursoriality and speed have long been areas of significant interest in theropod paleobiology as locomotory capacity, especially running ability, is critical in not just in prey pursuit but also to avoid become prey oneself. One aspect that is traditionally overlooked is the impact of allometry on running ability and the limiting effect of large body size. Since several different non-avian theropod lineages have each independently evolved body sizes greater than any known terrestrial carnivorous mammal, ∼1000kg or more, the effect that such larger mass has on movement ability and energetics is an area with significant implications for Mesozoic paleoecology. Here using expansive datasets, incorporating several different metrics to estimate body size, limb length and running speed, to calculate the effects of allometry running We test both on traditional metrics used to evaluate cursoriality in non-avian theropods such as distal limb length, relative hindlimb length as well as comparing the energetic cost savings of relative hindlimb elongation between members of the Tyrannosauridae and more basal megacarnivores such as Allosauroids or Ceratosauridae. We find that once the limiting effects of body size increase is incorporated, no commonly used metric including the newly suggested distal limb index (Tibia + Metatarsus/ Femur length) shows a significant correlation to top speed. The data also shows a significant split between large and small bodied theropods in terms of maximizing running potential suggesting two distinct strategies for promoting limb elongation based on the organisms’ size. For small and medium sized theropods increased leg length seems to correlate with a desire to increase top speed while amongst larger taxa it corresponds more closely to energetic efficiency and reducing foraging costs. We also find, using 3D volumetric mass estimates, that the Tyrannosauridae show significant cost of transport savings compared to more basal clades, indicating reduced energy expenditures during foraging and likely reduced need for hunting forays. This suggests that amongst theropods while no one strategy dictated hindlimb evolution. Amongst smaller bodied taxa the competing pressures of being both a predator and a prey item dominant while larger ones, freed from predation pressure, seek to maximize foraging ability. We also discuss the implications both for interactions amongst specific clades and Mesozoic paleobiology and paleoecological reconstructions as a whole.

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Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs

Cited by 121 publications

References 24 publications

Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China

Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China

Inferring lifestyle for Aves and Theropoda: a model based on curvatures of extant avian ungual bones

The fast and the frugal: Divergent locomotory strategies drive limb lengthening in theropod dinosaurs

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