The Diet of Early Birds Based on Modern and Fossil Evidence and a New Framework for its Reconstruction

Miller, Case Vincent; Pittman, Michael

doi:10.1002/essoar.10504068.1

Cited by 5 publications

(12 citation statements)

References 240 publications

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“…This dichotomy is a simplification of the range of likely ecologies exhibited by extinct taxa but is necessary because of the difficulty in reliably assigning specific ecologies based on dietary proxies (see Bestwick et al . (2018) and Miller & Pittman (2021) for recent reviews) and allows straightforward analyses. For biotope, archosauromorphs were categorized as either terrestrial, aquatic (including semi‐aquatic lifestyles) or aerial.…”

Section: Methodsmentioning

confidence: 99%

Relative skull size evolution in Mesozoic archosauromorphs: potential drivers and morphological uniqueness of erythrosuchid archosauriforms

et al. 2022

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Little is known about the large‐scale evolutionary patterns of skull size relative to body size, and the possible drivers behind these patterns, in Archosauromorpha. For example, the large skulls of erythrosuchids, a group of non‐archosaurian archosauromorphs from the Early and Middle Triassic, and of theropod dinosaurs are regarded as convergent adaptations for hypercarnivory. However, few investigations have explicitly tested whether erythrosuchid and theropod skulls are indeed disproportionately large for their body size, and whether this trend is driven by hypercarnivory. Here, we investigate archosauromorph relative skull size evolution, examining the scaling relationships between skull and body size of Palaeozoic and Mesozoic archosauromorphs using a robust phylogenetic framework and assessing the influence of potential drivers, such as taxonomy, diet, locomotory mode and inhabited biotope. Our results show that archosauromorph relative skull sizes are largely determined by phylogeny and that the other drivers have much weaker levels of influence. We find negative allometric scaling of skull size with respect to body size when all studied archosauromorphs are analysed. Within specific groups, skull size scales with positive allometry in non‐archosaurian archosauromorphs and, interestingly, scales isometrically in theropods. Ancestral reconstructions of skull–femur size ratio reveal a disproportionately large skull at the base of Erythrosuchidae and proportionately sized skulls at the bases of Theropoda, Carnosauria and Tyrannosauroidea. Relative skull sizes of erythrosuchids and theropods are therefore distinct from each other, indicating that disproportionately large skulls are not a prerequisite for hypercarnivory in archosauromorphs, and that erythrosuchids exhibit a bauplan unique among terrestrial Mesozoic carnivores.

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Section: Methodsmentioning

confidence: 99%

Relative skull size evolution in Mesozoic archosauromorphs: potential drivers and morphological uniqueness of erythrosuchid archosauriforms

et al. 2022

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“…The occurrence of specialised seed-dispersal by animals during the Early Cretaceous has previously been proposed indirectly, based on the presence of aril-producing gymnosperm and early fruit-producing angiosperms (Eriksson, 2008;Eriksson et al, 2000a). However, the identification of these frugivores has been uncertain and frugivory was almost unmentioned in the recent review of early bird diets (Miller and Pittman, 2021). Strong indications for at least seasonal frugivory in Jeholornis provides direct evidence of this for the first time.…”

Section: Discussionmentioning

confidence: 95%

“…and a recent review identified these Miller and Pittman, 2021). Clarifying between these two hypotheses has significant implications with regards to the early evolution of bird-plant interactions, because frugivory results from beneficial coevolutionary mutualism, whereas granivory does not.…”

Section: Introductionmentioning

confidence: 99%

Earliest evidence for fruit consumption and potential seed dispersal by birds

Wang

McDonald

et al. 2022

eLife

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The Early Cretaceous diversification of birds was a major event in the history of terrestrial ecosystems, occurring during the earliest phase of the Cretaceous Terrestrial Revolution, long before the origin of the bird crown-group. Frugivorous birds play an important role in seed dispersal today. However, evidence of fruit consumption in early birds from outside the crown-group has been lacking. Jeholornis is one of the earliest-diverging birds, only slightly more crownward than Archaeopteryx, but its cranial anatomy has been poorly understood, limiting trophic information which may be gleaned from the skull. Originally hypothesised to be granivorous based on seeds preserved as gut contents, this interpretation has become controversial. We conducted high-resolution synchrotron tomography on an exquisitely preserved new skull of Jeholornis, revealing remarkable cranial plesiomorphies combined with a specialised rostrum. We use this to provide a near-complete cranial reconstruction of Jeholornis, and exclude the possibility that Jeholornis was granivorous, based on morphometric analyses of the mandible (3D) and cranium (2D), and comparisons with the 3D alimentary contents of extant birds. We show that Jeholornis provides the earliest evidence for fruit consumption in birds, and indicates that birds may have been recruited for seed dispersal during the earliest stages of the avian radiation. As mobile seed dispersers, early frugivorous birds could have expanded the scope for biotic dispersal in plants, and might therefore explain, at least in part, the subsequent evolutionary expansion of fruits, indicating a potential role of bird–plant interactions in the Cretaceous Terrestrial Revolution.

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“…PMoL-AB00178 is smaller than most known confuciusornithid specimens, even though it represents one of the few such specimens assignable to the oldest ontogenetic stage. PMoL-AB00178 has an estimated body mass (BM) of 174 g based on a multivariate equation 17 , while most other known adult or subadult confuciusornithid specimens have greater estimated body masses (BMs), ranging up to 801 g for the largest known individual of Confuciusornis 17,18 (also see Supplementary Table 3). PMoL-AB00178 thus belongs to a truly small-bodied confuciusornithid species.…”

Section: Systematicmentioning

confidence: 99%

A new confuciusornithid bird with a secondary epiphyseal ossification reveals phylogenetic changes in confuciusornithid flight mode

Wang

Zhang

et al. 2022

Commun Biol

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The confuciusornithids are the earliest known beaked birds, and constitute the only species-rich clade of Early Cretaceous pygostylian birds that existed prior to the cladogenesis of Ornithothoraces. Here, we report a new confuciusornithid species from the Lower Cretaceous of western Liaoning, northeastern China. Compared to other confuciusornithids, this new species and the recently reported Yangavis confucii both show evidence of stronger flight capability, although the wings of the two taxa differ from one another in many respects. Our aerodynamic analyses under phylogeny indicate that varying modes of flight adaptation emerged across the diversity of confuciusornithids, and to a lesser degree over the course of their ontogeny, and specifically suggest that both a trend towards improved flight capability and a change in flight strategy occurred in confuciusornithid evolution. The new confuciusornithid differs most saliently from other Mesozoic birds in having an extra cushion-like bone in the first digit of the wing, a highly unusual feature that may have helped to meet the functional demands of flight at a stage when skeletal growth was still incomplete. The new find strikingly exemplifies the morphological, developmental and functional diversity of the first beaked birds.

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The Diet of Early Birds Based on Modern and Fossil Evidence and a New Framework for its Reconstruction

Cited by 5 publications

References 240 publications

Relative skull size evolution in Mesozoic archosauromorphs: potential drivers and morphological uniqueness of erythrosuchid archosauriforms

Relative skull size evolution in Mesozoic archosauromorphs: potential drivers and morphological uniqueness of erythrosuchid archosauriforms

Earliest evidence for fruit consumption and potential seed dispersal by birds

A new confuciusornithid bird with a secondary epiphyseal ossification reveals phylogenetic changes in confuciusornithid flight mode

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