The Avian Acetabulum: Small Structure, but Rich with Illumination and Questions DOI Creative Commons
Alan Feduccia

Diversity, Journal Year: 2023, Volume and Issue: 16(1), P. 20 - 20

Published: Dec. 27, 2023

The idea that birds are maniraptoran theropod dinosaurs is now considered an evolutionary consensus. An “open” (i.e., completely or substantially perforate) acetabulum important synapomorphy verifying the bird–dinosaur nexus. Here, I present anatomical evidence from and its appurtenances, supracetabular crest antitrochanter, hip anatomy differs between birds. Given thin bone of acetabular walls varied tissue, both hard soft, in region especially lower part basin, it apparent many avian skeletons exhibit some loss soft tissue bone, perhaps related to changes gait, but also dramatic trend reduction associated with flight, more advanced crown taxa. Many basal early diverging neornithines tend have a nearly closed partially acetabula, thus rendering current terms “closed” acetabula inaccurate; they should be modified replaced. new presented here, relationship “dinosaurs” must re-evaluated.

Language: Английский

Origin and Evolution of Birds DOI
Gary Ritchison

Fascinating life sciences, Journal Year: 2023, Volume and Issue: unknown, P. 1 - 154

Published: Jan. 1, 2023

Language: Английский

Citations

44
Genomes, fossils, and the concurrent rise of modern birds and flowering plants in the Late Cretaceous DOI Creative Commons
Shaoyuan Wu, Frank E. Rheindt, Jin Zhang

et al.

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(8)

Published: Feb. 12, 2024

The phylogeny and divergence timing of the Neoavian radiation remain controversial despite recent progress. We analyzed genomes 124 species across all orders, using data from 25,460 loci spanning four DNA classes, including 5,756 coding sequences, 12,449 conserved nonexonic elements, 4,871 introns, 2,384 intergenic segments. conducted a comprehensive sensitivity analysis to account for heterogeneity different leading an optimal tree Neoaves with high resolution. This features novel dichotomy comprising two monophyletic clades: previously recognized Telluraves (land birds) newly circumscribed Aquaterraves (waterbirds relatives). Molecular dating analyses 20 fossil calibrations indicate that diversification modern birds began in Late Cretaceous underwent constant steady KPg boundary, concurrent rise angiosperms as well other major Cenozoic animal groups placental multituberculate mammals. catastrophe had limited impact on avian evolution compared Paleocene–Eocene Thermal Maximum, which triggered rapid seabirds. Our findings suggest followed slow process gradualism rather than punctuated equilibrium, interruption by catastrophe. study places bird into new context within vertebrates, ramifications Earth’s biota.

Language: Английский

Citations

24
The influence of soft tissue volume on estimates of skeletal pneumaticity: implications for fossil archosaurs DOI Creative Commons
Maria Grace Burton, Juan Benito,

Kirsty Mellor

et al.

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2025, Volume and Issue: 380(1920)

Published: Feb. 27, 2025

Air space proportion (ASP), the volume fraction in bone that is occupied by air, frequently applied as a measure for quantifying extent of skeletal pneumaticity extant and fossil archosaurs. Nonetheless, ASP estimates rely on key assumption: soft tissue mass within pneumatic bones negligible, an assumption has rarely been explicitly acknowledged or tested. Here, we provide first comparisons between estimated air (where internal cavity assumed to be completely air-filled) true (ASPt, where tissues present cavities fresh specimens are considered). Using birds model archosaurs exhibiting postcranial pneumaticity, find ASPt significantly lower than ASP, raising important consideration should investigations evolution bulk density extinct archosaurs, well volume-based archosaur body mass. We advocate difference studies seeking quantify avoid risk systematically overestimating composed air. This article part theme issue ‘The biology avian respiratory system’.

Language: Английский

Citations

3
Whence the birds: 200 years of dinosaurs, avian antecedents DOI Creative Commons
Daniel J. Field, Maria Grace Burton, Juan Benito

et al.

Biology Letters, Journal Year: 2025, Volume and Issue: 21(1)

Published: Jan. 1, 2025

Among the most revolutionary insights emerging from 200 years of research on dinosaurs is that clade Dinosauria represented by approximately 11 000 living species birds. Although origin birds among has been reviewed extensively, recent have witnessed tremendous progress in our understanding deep evolutionary origins numerous distinctive avian anatomical systems. These advances enabled exciting new fossil discoveries, leading to an ever-expanding phylogenetic framework with which pinpoint characteristic features. The present review focuses four notable systems whose Mesozoic history greatly clarified discoveries: brain, kinetic palate, pectoral girdle and postcranial skeletal pneumaticity.

Language: Английский

Citations

1
Cretaceous ornithurine supports a neognathous crown bird ancestor DOI
Juan Benito, Pei‐Chen Kuo, Klara E. Widrig

et al.

Nature, Journal Year: 2022, Volume and Issue: 612(7938), P. 100 - 105

Published: Nov. 30, 2022

Language: Английский

Citations

34
Basal Anseriformes from the Early Paleogene of North America and Europe DOI Creative Commons
Peter Houde, Meig Dickson,

Dakota Camarena

et al.

Diversity, Journal Year: 2023, Volume and Issue: 15(2), P. 233 - 233

Published: Feb. 7, 2023

We describe nearly complete skeletons of basal Anseriformes from the Latest Paleocene to early Eocene North America and Europe. Collectively, these birds appear be representative anseriforms near divergence Anhimae Anseres, but their exact positions relative clades remains uncertain. A new family, Anachronornithidae nov. fam., is erected on basis one these, Anachronornis anhimops gen., gen. et sp., which others cannot confidently assigned. The fossils augment a growing collection Pan-Anseriformes, in diversity do not paint an unambiguous picture phylogeny or character state evolution path within crown-Anseriformes. similar some aspects both cranial postcranial anatomy other well-represented Paleogene members such as Presbyornis Wetmore, 1926. However, it exhibits more landfowl-like bill, like that unlike spatulate bill Anseres. Additional specimens uncertain affinities Europe further complicate interpretation polarity due mosaicism primitive derived characters they exhibit.

Language: Английский

Citations

12
Taphonomic damage obfuscates interpretation of the retroarticular region of the Asteriornis mandible DOI Creative Commons

Abi Crane,

Juan Benito, Albert Chen

et al.

Geobios, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 1, 2024

Asteriornis maastrichtensis, from the latest Cretaceous of Belgium, is among oldest known crown bird fossils, and its three-dimensionally preserved skull provides most substantial insights into cranial morphology early birds to date. Phylogenetic analyses recovered as a total-group member Galloanserae, clade uniting Galliformes Anseriformes. One important feature supporting this placement was enlargement retroarticular processes, which form elongate caudal extensions mandible in extant Galloanserae. Here, we reinterpret jaw illustrate that caudalmost portion mandibles are fact not preserved. Instead, extremities both left right mandibular rami extend surface fossil block containing holotype skull, where they have eroded away. The originally identified process – exhibits orientation strikingly similar processes certain galloanserans, including Palaeogene total-clade anseriforms Conflicto Nettapterornis instead represents twisted caudally displaced medial process. Nonetheless, anatomical comparisons with taxa reveal cannot exclude possibility exhibited robust comparable those In light reinterpreted mandible, update original character matrix used investigate phylogenetic relationships perform revised analyses, continue support galloanseran, initially interpreted. We demonstrate additional morphological traits position provide new data on nature distribution birds.

Language: Английский

Citations

4
The Lithornithiformes (Aves) from the early Eocene London Clay of Walton‐on‐the‐Naze (Essex, UK) DOI Creative Commons
Gérald Mayr, Andrew C. Kitchener

Papers in Palaeontology, Journal Year: 2025, Volume and Issue: 11(1)

Published: Jan. 1, 2025

Abstract We describe multiple partial skeletons and isolated bones of the palaeognathous Lithornithiformes from early Eocene London Clay Walton‐on‐the‐Naze (Essex, UK). The well‐preserved specimens are assigned to at least four species taxa Lithornis Pseudocrypturus. Two identified as L. nasi cf. grandei . latter species, which was established for fossils North American Green River Formation, initially monotypic taxon Calciavis , is here considered synonymous with further new tentatively referred Pseudocrypturus described ? P. danielsi gracilipes In previous analyses, lithornithiforms most often resulted sister either Tinamiformes or all crown group Palaeognathae. detail that current morphological evidence conforms best a position these birds outside Palaeognathae discuss previously unrecognized plesiomorphic features foot pelvis, support this phylogenetic placement.

Language: Английский

Citations

0
Cretaceous bird from Brazil informs the evolution of the avian skull and brain DOI Creative Commons
Luis M. Chiappe, Guillermo Navalón, Agustín G. Martinelli

et al.

Nature, Journal Year: 2024, Volume and Issue: 635(8038), P. 376 - 381

Published: Oct. 30, 2024

Abstract A dearth of Mesozoic-aged, three-dimensional fossils hinders understanding the origin distinctive skull and brain modern (crown) birds 1 . Here we report Navaornis hestiae gen. et sp. nov., an exquisitely preserved fossil species from Late Cretaceous Brazil. The is toothless large-eyed, with a vaulted cranium closely resembling condition in crown birds; however, phylogenetic analyses recover Enantiornithes, highly diverse clade Mesozoic stem birds. Despite overall geometry quantitatively indistinguishable birds, retains numerous plesiomorphies including maxilla-dominated rostrum, akinetic palate, diapsid temporal configuration, small cerebellum weakly expanded telencephalon. These archaic neurocranial traits are combined bird-like degree flexion bony labyrinth comparable shape to those many but substantially larger. Altogether, emergent cranial shows unprecedented similarity between enantiornithines, groups last sharing common ancestor more than 130 million years ago 2 provides long-sought insight into detailed endocranial morphology phylogenetically crownward Archaeopteryx , clarifying pattern timing by which neuroanatomy living was assembled.

Language: Английский

Citations

3
Reconstructing locomotor ecology of extinct avialans: a case study of Ichthyornis comparing sternum morphology and skeletal proportions DOI Open Access
Talia M. Lowi‐Merri, Oliver E. Demuth, Juan Benito

et al.

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2023, Volume and Issue: 290(1994)

Published: March 8, 2023

Avian skeletal morphology is associated with locomotor function, including flight style, swimming and terrestrial locomotion, permits informed inferences on locomotion in extinct taxa. The fossil taxon Ichthyornis (Avialae: Ornithurae) has long been regarded as highly aerial, similar to terns or gulls (Laridae), features resembling foot-propelled diving adaptations. However, rigorous testing of hypotheses yet be performed , despite its notable phylogenetic position one the most crownward stem birds. We analysed separate datasets three-dimensional sternal shape (geometric morphometrics) proportions (linear measurements across skeleton), examine how well these data types predict traits Neornithes. then used this information infer capabilities Ichthyornis. find strong support for both soaring Further, provide complementary avian locomotion: allow better predictions capacity flight, whereas predicts variation more specific abilities such soaring, escape burst flight. These results have important implications future studies avialan ecology underscore importance closely considering sternum investigations bird locomotion.

Language: Английский

Citations

9