Genomes, fossils, and the concurrent rise of modern birds and flowering plants in the Late Cretaceous (2 Viewers)

[Fred Ruhe]

Shaoyuan Wu, Frank E. Rheindt, Jin Zhang Jiajia Wang, Lei Zhang, Cheng Quan , Zhiheng Li, Min Wang, Feixiang Wu,
Yanhua Qu, Scott V. Edwards, Zhonghe Zhou, and Liang Liu, 2024

Genomes, fossils, and the concurrent rise of modern birds and flowering plants in the Late Cretaceous

Proceedings of the National Academy of Sciences of the United States of America. 121 (8). e2319696121.
doi:10.1073/pnas.2319696121

Significance

Despite modern DNA advances, scientists still know little about how and when early bird groups evolved. Using new approaches to mine genomic information among 124 species covering most of modern bird diversity, we found that the main lineages of birds first divided into two groups: one mostly land-based and the other containing water-associated species. We demonstrate that modern birds date back further than previously assumed, much earlier than the dinosaurian extinction event, which seems to have had a limited impact on birds’ evolution. Instead, a warming event around ~55 Mya appears to have triggered the diversification of modern seabirds. Our study indicates that the radiation of modern birds was in remarkable lockstep with that of flowering plants and other organisms.

Abstract: https://www.pnas.org/doi/10.1073/pnas.2319696121

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

Enjoy,

Fred

 

[Fred Ruhe]

Fig. 1. Phylogenetic relationships of modern birds. The time-calibrated tree of 124 avian species was constructed using the coalescence-based method NJst from a combination of maximum likelihood gene trees of CDS, intron, and intergenic segments after removing 30% outliers. Numbers on nodes indicate bootstrap support values, with numbers >90% not shown. Background shading indicates the Late Cretaceous era.


Fig. 2. Interordinal diversification of modern birds and placental mammals from the Late Cretaceous to the Paleogene. Note that both crown Aves and placental mammals underwent a constant and steady differentiation across the KPg boundary, without apparent interruption by the KPg mass extinction event. The green background indicates the increase of taxonomic diversity of flowering plants. The data on placental mammal and angiosperm diversity are based on Liu
et al. (25) and Condamine et al. (26), respectively.

Fred

 

[Xenospiza]

Thanks for the pictures Fred; some criticism already here: Phylogeny of birds

 

[Jim LeNomenclatoriste]

I am almost certain that this will not be the last article of its kind because if the position of many clades is well defined, that of the Hoazin, Flamingos and Grebes varies from one study to another

 

[Fred Ruhe]

Here is the full paper.

Fred

 

[THE_FERN]

Fig. 1. Phylogenetic relationships of modern birds. The time-calibrated tree of 124 avian species was constructed using the coalescence-based method NJst from a combination of maximum likelihood gene trees of CDS, intron, and intergenic segments after removing 30% outliers. Numbers on nodes indicate bootstrap support values, with numbers >90% not shown. Background shading indicates the Late Cretaceous era.
View attachment 1559373

Fig. 2. Interordinal diversification of modern birds and placental mammals from the Late Cretaceous to the Paleogene. Note that both crown Aves and placental mammals underwent a constant and steady differentiation across the KPg boundary, without apparent interruption by the KPg mass extinction event. The green background indicates the increase of taxonomic diversity of flowering plants. The data on placental mammal and angiosperm diversity are based on Liu
et al. (25) and Condamine et al. (26), respectively.
View attachment 1559374
Fred

Without looking at this forensically: a brief glance suggests it shows the opposite of what they say. Rate of diversification is much greater up until the KPg boundary when it slows down considerably. Of course, making a statement about rate of diversification like this requires the points to be "equal" in some sense and these aren't (which probably renders the analysis here meaningless)