Oviraptorosaur anatomy, diversity and ecology in the Nemegt Basin

Funston, Gregory F.; Mendonca, Steven E.; Currie, Philip J.; Барсболд, Ринчен

doi:10.1016/j.palaeo.2017.10.023

Cited by 49 publications

(73 citation statements)

References 48 publications

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“…Further, within Oviraptorosauria, derived forms (e.g. Citipati, Khaan, Heyuannia, Gigantoraptor ; Clark et al ., 2001; Xu et al , 2009; Balanoff and Norell, 2012; Funston et al ., 2018) show signs of pneumatization in the tail, which are absent in Similicaudipteryx and Caudipteryx (Zhou et al , 2000; He et al ., 2008). Megaraptora shows a strong pneumatization of the tail in its basal forms (e.g.…”

Section: Discussionmentioning

confidence: 99%

Histology and pneumaticity of Aoniraptor libertatem (Dinosauria, Theropoda), an enigmatic mid‐sized megaraptoran from Patagonia

2020

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Aoniraptor libertatem is a mid‐sized megaraptoran that comes from the Late Cretaceous (Turonian) Huincul Formation at Río Negro province, Patagonia, Argentina. In this study, we conducted a detailed analysis of pneumaticity of the sacrum and tail of Aoniraptor. This shows a complex structure within these vertebrae, being composed by small diverticulae surrounding large pneumatic canals and a central chamber that opens outside through pleurocoels or pneumatic canals. Further, we carried out a histologic analysis which confirms the pneumatic nature of these anatomical features. Both analyses found that chevrons in Aoniraptor were invaded by pneumaticity, a feature that appears to be unique to this taxon. In addition, a comparative analysis between Aoniraptor and other theropods (e.g. Gualicho and other megaraptorans) was carried out. This resulted in the modification of previous schemes about the evolution of pneumaticity through Theropoda, the finding of some evolutionary pneumatic traits through Megaraptora, and the usefulness of pneumatic traits as a taxonomic tool.

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Section: Discussionmentioning

confidence: 99%

Histology and pneumaticity of Aoniraptor libertatem (Dinosauria, Theropoda), an enigmatic mid‐sized megaraptoran from Patagonia

2020

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“…It is important to note that scansoriopterygids retained striking plesiomorphic traits in their pectoral girdle, including a caudoventrally oriented scapulocoracoid glenoid, a subrectangular coracoid with a reduced biceps tubercle, and a distally expanded scapular blade. These features also shared by oviraptorosaurs as Avimimus and Heyuannia (Lü et al, 2005;Funston et al, 2017), among other non-paravian/pennaraptoran theropods.…”

Section: Phylogenetic Relationships Of Archaeopterygidae and Scansorimentioning

confidence: 98%

“…On the other hand, Xu et al (2010) suggested that scansoriopterygids might be related to oviraptorosaurs, a hypothesis cladistically supported by Agnolin and Novas (2013) and later endorsed by O'Connor and Sullivan (2014). Zhang et al (2008) and Foth et al (2014) defended the putative avialan affinities of scansoriopterygids based on a combination of characters that is also shared with oviraptorosaurs, and especially with caenagnathids and avimimids (Kurzanov, 1981;Osmólska et al, 2004;Funston et al, 2017;see Agnolin and Novas, 2013), including: dentary and maxillary teeth devoid of serrations and with roots that are subcircular in cross-section, relatively few caudal vertebrae, fused metatarsal cap, and pedal phalanx II-2 longer than phalanx II-1.…”

Section: Phylogenetic Relationships Of Archaeopterygidae and Scansorimentioning

confidence: 99%

“…Furthermore, scansoriopterygids share with oviraptorosaurs some anatomical traits that are uncommon among theropods. For example, Epidexipteryx and such oviraptorosaurs as Nomingia share a distally tapering pygostyle-like structure formed by unfused caudals at the end of the tail (Barsbold et al, 2000;Funston et al, 2017; also present in therizinosaurs, see Xu et al, 2003).…”

Section: Phylogenetic Relationships Of Archaeopterygidae and Scansorimentioning

confidence: 99%

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Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview

et al. 2019

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Recent years witnessed the discovery of a great diversity of early birds as well as closely related non-avian theropods, which modified previous conceptions about the origin of birds and their flight. We here present a review of the taxonomic composition and main anatomical characteristics of those theropod families closely related with early birds, with the aim of analyzing and discussing the main competing hypotheses pertaining to avian origins. We reject the postulated troodontid affinities of anchiornithines, and the dromaeosaurid affinities of microraptorians and unenlagiids, and instead place these groups as successive sister taxa to Avialae. Aiming to evaluate previous phylogenetic analyses, we recoded unenlagiids in the traditional TWiG data matrix, which resulted in a large polytomy at the base of Pennaraptora. This indicates that the TWiG phylogenetic scheme needs a deep revision. Regarding character evolution, we found that: (1) the presence of an ossified sternum goes hand in hand with that of ossified uncinate processes; (2) the presence of foldable forelimbs in basal archosaurs indicates widespread distribution of this trait among reptiles, contradicting previous proposals that forelimb folding driven by propatagial and associated tendons was exclusive to the avian lineage; (3) in basal paravians and avialans (e.g., Archaeopteryx, Anchiornis) the wings are relatively large and wide, with relatively short rectricial feathers, a rounded alar contour, and a convex leading margin. These taxa exhibit restricted forelimb folding capability with respect to more derived birds, their hands being preserved at angles of flexion (with respect to the radius/ulna) of no less than 90 • . In more derived birds, however, the rectrices are notably elongate and the angle between the hand and forearm is much less than 90 • , indicating not only increased forelimb folding capability but also an increased variety of wingbeat movements during flight. Because of the strong similarities in pectoral girdle configuration between ratites and basal avialans and paravians, it is possible to infer that the main forelimb movements were similar in all these taxa, lacking the complex dorsoventral wing excursion characteristic of living neognathans.

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“…Sauropods were rare in those communities where Tyrannosauridae existed [60], with only a single taxon, Alamosaurus, known from North America restricted to the Southernmost part of Tyrannosaurus' range [61], and two (c.f. [62]) small sauropods from the Nemegt which are minor members of the fauna [63]. For tyrannosaurids the most common larger prey taxa are herds of ceratopsians and hadrosaurs which are on the order of 1/5-1/10 the mass of the sauropod prey available to the larger allosauroids and basal tetanurans [52].…”

Section: Why Tyrannosaurids?mentioning

confidence: 99%

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

Dececchi¹,

Mloszewska²,

Holtz³

et al. 2019

Preprint

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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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Oviraptorosaur anatomy, diversity and ecology in the Nemegt Basin

Cited by 49 publications

References 48 publications

Histology and pneumaticity of Aoniraptor libertatem (Dinosauria, Theropoda), an enigmatic mid‐sized megaraptoran from Patagonia

Histology and pneumaticity of Aoniraptor libertatem (Dinosauria, Theropoda), an enigmatic mid‐sized megaraptoran from Patagonia

Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview

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

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