First report of gastroliths in the Early Cretaceous basal bird Jeholornis

O’Connor, Jingmai K.; Wang, Xiaoli; Sullivan, Corwin; Wang, Yan; Zheng, Xiaoting; Hu, Han; Zhang, Xiaomei; Zhou, Zhonghe

doi:10.1016/j.cretres.2017.10.031

“…A succession of events implicated in the destruction of global forests would have primarily affected arboreal taxa, including shockwaves knocking down trees immediately after the impact, wild fires directly eliminating forest habitats, and reduced light levels and associated global cooling delaying forest recovery. Although a multitude of factors undoubtedly influenced avian evolution at the end-Cretaceous mass extinction, including diet [24,28], body size [19], breeding habits [27], and flight capacity [53], selection for non-arboreal habits appears to have left an indelible mark on the early evolutionary history of crown birds, clearly discernible more than 66 million years later.…”

Section: Resultsmentioning

confidence: 99%

“…Research on the evolution of neornithine breeding habits [27] suggests that relative to Enantiornithes, ancestral crown birds may have acquired proportionally larger eggs and alternative nesting substrates. Moreover, evolution of a crown-grade alimentary system has additionally been posited as a factor that may have influenced the post-K-Pg survival of Neornithes [28]; both of these latter hypotheses are tantalizing and warrant additional research.…”

Section: Factors Influencing the Post-cretaceous Survival Of Crown Birdsmentioning

confidence: 99%

Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction

Field

¹

,

Bercovici

²

,

Berv

³

et al. 2018

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The fossil record and recent molecular phylogenies support an extraordinary early-Cenozoic radiation of crown birds (Neornithes) after the Cretaceous-Paleogene (K-Pg) mass extinction [1-3]. However, questions remain regarding the mechanisms underlying the survival of the deepest lineages within crown birds across the K-Pg boundary, particularly since this global catastrophe eliminated even the closest stem-group relatives of Neornithes [4]. Here, ancestral state reconstructions of neornithine ecology reveal a strong bias toward taxa exhibiting predominantly non-arboreal lifestyles across the K-Pg, with multiple convergent transitions toward predominantly arboreal ecologies later in the Paleocene and Eocene. By contrast, ecomorphological inferences indicate predominantly arboreal lifestyles among enantiornithines, the most diverse and widespread Mesozoic avialans [5-7]. Global paleobotanical and palynological data show that the K-Pg Chicxulub impact triggered widespread destruction of forests [8, 9]. We suggest that ecological filtering due to the temporary loss of significant plant cover across the K-Pg boundary selected against any flying dinosaurs (Avialae [10]) committed to arboreal ecologies, resulting in a predominantly non-arboreal post-extinction neornithine avifauna composed of total-clade Palaeognathae, Galloanserae, and terrestrial total-clade Neoaves that rapidly diversified into the broad range of avian ecologies familiar today. The explanation proposed here provides a unifying hypothesis for the K-Pg-associated mass extinction of arboreal stem birds, as well as for the post-K-Pg radiation of arboreal crown birds. It also provides a baseline hypothesis to be further refined pending the discovery of additional neornithine fossils from the Latest Cretaceous and earliest Paleogene.

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“…Gastroliths discovered in basal birds such as the granivorous Sapeornis and Jeholornis, and a cohesive gastric pellet of a piscivorous enantiornithine bird from the Early Cretaceous point out that the muscular gizzard was indeed present in early birds (Wang et al 2016, O'Connor et al 2017). Moreover, two bone aggregates found in the stomach of the early tetrapteryx bird Microraptor gui (IVPP V17972A) might be tentatively interpreted as gastric pellets, situated in the muscular and glandular chambers of stomach (see O'Connor et al 2011).…”

Section: Digestion In Dinosaurs and Early Birdsmentioning

confidence: 99%

“…In contrast, as gastric pellets travels up from the muscular stomach to the glandular stomach, where they stay awhile for further digestion and in consequence block the alimentary canal, owls cannot consume more foodstuff until they regurgitate the residues from the previous meal (Wang et al 2009). This is because owls lack the esophageal crop, which was probably absent also in the basal bird Jeholornis (O'Connor et al 2017). Dissection of crocodiles revealed the presence of gastric pellets in the upper region of stomach where digestive acids are acting (Fisher 1981).…”

Section: Digestion In Dinosaurs and Early Birdsmentioning

confidence: 99%

Comparative digestive physiology of archosaurs with notes on bird origins

Bajdek

¹

2018

Preprint

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It is widely accepted that birds evolved from theropod dinosaurs, and few paleontologists disagree preferring a more ancient split of the avian and dinosaur lineages. The difference in digestive physiology between members of the theropod and crocodile lineages, documented by fossil feces and gut contents, offers an opportunity to test these phylogenetic hypotheses. Birds share with crocodiles the functional gizzard that contains swallowed stones and where gastric pellets are formed before regurgitation, as well as a mechanism that prevents the passage of indigestible residues into the intestine. Both these adaptations are missing in unquestionable theropod groups (compsognathids, tyrannosaurids, allosaurids, coelophysids). The theropod ancestry of birds implies reappearance and strong development of a specific stomach functionality that either had been already lost in the theropod dinosaurs or was never present in their lineage. Coprolites of early archosaurs contain undigested bones, which suggests a short digestion time and higher metabolic rates than in extant crocodiles. Early archosaurs were similar to birds, but not to dinosaurs, in all these aspects of physiology.

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“…In contrast, as gastric pellets travels up from the muscular stomach to the glandular stomach, where they stay awhile for further digestion and in consequence block the alimentary canal, owls cannot consume more foodstuff until they regurgitate the residues from the previous meal (Wang et al 2009). This is because owls lack the esophageal crop, which was probably absent also in the basal bird Jeholornis (O'Connor et al 2017). Dissection of crocodiles revealed the presence of gastric pellets in the upper region of stomach where digestive acids are acting (Fisher 1981).…”

Section: Digestion In Dinosaurs and Early Birdsmentioning

confidence: 99%

Comparative digestive physiology of archosaurs with notes on bird origins

Bajdek

¹

2018

Preprint

1

0

View full text Add to dashboard Cite

It is widely accepted that birds evolved from theropod dinosaurs, and few paleontologists disagree preferring a more ancient split of the avian and dinosaur lineages. The difference in digestive physiology between members of the theropod and crocodile lineages, documented by fossil feces and gut contents, offers an opportunity to test these phylogenetic hypotheses. Birds share with crocodiles the functional gizzard that contains swallowed stones and where gastric pellets are formed before regurgitation, as well as a mechanism that prevents the passage of indigestible residues into the intestine. Both these adaptations are missing in unquestionable theropod groups (compsognathids, tyrannosaurids, allosaurids, coelophysids). The theropod ancestry of birds implies reappearance and strong development of a specific stomach functionality that either had been already lost in the theropod dinosaurs or was never present in their lineage. Coprolites of early archosaurs contain undigested bones, which suggests a short digestion time and higher metabolic rates than in extant crocodiles. Early archosaurs were similar to birds, but not to dinosaurs, in all these aspects of physiology.

show abstract

First report of gastroliths in the Early Cretaceous basal bird Jeholornis

Cited by 31 publications

References 24 publications

Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction

Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction

Comparative digestive physiology of archosaurs with notes on bird origins

Comparative digestive physiology of archosaurs with notes on bird origins

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