Plotopterid skull from Eocene of Washington State + proto-feather-like structures created in chicken + avian genomic change rate + more free avian pdfs

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

Some recent avian papers:

Free pdf:

Gerald Mayr, James L. Goedert & Adrian Richter (2025)
Nearly complete late Eocene skull from the North Pacific elucidates the cranial morphology and affinities of the penguin-like Plotopteridae
The Science of Nature 112: 27
doi: https://doi.org/10.1007/s00114-025-01977-1
https://link.springer.com/article/10.1007/s00114-025-01977-1


The extinct Plotopteridae were penguin-like, wing-propelled diving birds of the North Pacific. Recently, the oldest and most complete plotopterid skull has been discovered in the late Eocene lower part of the Lincoln Creek Formation, southern Olympic Peninsula (Washington State, USA), and informs the poorly known cranial morphology of these birds. This skull is somewhat larger than previously described partial skulls from the Oligocene Pysht Formation of the northern Olympic Peninsula, from which it also differs in the shape of the nostrils. It may represent the genus Klallamornis, but a definitive taxonomic assignment is not yet possible. The specimen corroborates a sister group relationship of plotopterids to the suliform Suloidea and exhibits a notable character mosaic. Whereas the long rostrum most closely resembles that of the Fregatidae and some Phalacrocoracidae, the neurocranium is more similar to that of the Sulidae. An arcuate rostral ridge of the basicranium is otherwise only known from the Sphenisciformes, and a pair of prominent longitudinal ridges along the ventral surface of the rostrum is an autapomorphy of plotopterids. The small nostrils are situated at the caudal ends of conspicuous sulci, which are interpreted as vestiges of long, slit-like nostrils and are much less pronounced in extant Suliformes. Long, slit-like nostrils occur in stem group Sphenisciformes and may also have been present in stem group Fregatidae, in which case the nostrils were reduced twice within Suliformes, presumably to prevent salt water influx into the nasal cavity.

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Free pdf:

Rory L. Cooper & Michel C. Milinkovitch (2025)
In vivo sonic hedgehog pathway antagonism temporarily results in ancestral proto-feather-like structures in the chicken.
PLoS Biology 23(3): e3003061
doi: https://doi.org/10.1371/journal.pbio.3003061
https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003061


The morphological intricacies of avian feathers make them an ideal model for investigating embryonic patterning and morphogenesis. In particular, the sonic hedgehog (Shh) pathway is an important mediator of feather outgrowth and branching. However, functional in vivo evidence regarding its role during feather development remains limited. Here, we demonstrate that an intravenous injection of sonidegib, a potent Shh pathway inhibitor, at embryonic day 9 (E9) temporarily produces striped domains (instead of spots) of Shh expression in the skin, arrests morphogenesis, and results in unbranched and non-invaginated feather buds—akin to proto-feathers—in embryos until E14. Although feather morphogenesis partially recovers, hatched treated chickens exhibit naked skin regions with perturbed follicles. Remarkably, these follicles are subsequently reactivated by seven weeks post-hatching. Our RNA-sequencing data and rescue experiment using Shh-agonism confirm that sonidegib specifically down-regulates Shh pathway activity. Overall, we provide functional evidence for the role of the Shh pathway in mediating feather morphogenesis and confirm its role in the evolutionary emergence and diversification of feathers.

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Free pdf:

David A. Duchêne, Al-Aabid Chowdhury, Jingyi Yang, Maider Iglesias-Carrasco, Josefin Stiller, Shaohong Feng, Samir Bhatt, M. Thomas P. Gilbert, Guojie Zhang, Joseph A. Tobias & Simon Y. W. Ho (2025)
Drivers of avian genomic change revealed by evolutionary rate decomposition
Nature (advance online publication)
doi: https://doi.org/10.1038/s41586-025-08777-7
https://www.nature.com/articles/s41586-025-08777-7


Modern birds have diversified into a striking array of forms, behaviours and ecological roles. Analyses of molecular evolutionary rates can reveal the links between genomic and phenotypic change, but disentangling the drivers of rate variation at the whole-genome scale has been difficult. Using comprehensive estimates of traits and evolutionary rates across a family-level phylogeny of birds, we find that genome-wide mutation rates across lineages are predominantly explained by clutch size and generation length, whereas rate variation across genes is driven by the content of guanine and cytosine. Here, to find the subsets of genes and lineages that dominate evolutionary rate variation in birds, we estimated the influence of individual lineages on decomposed axes of gene-specific evolutionary rates. We find that most of the rate variation occurs along recent branches of the tree, associated with present-day families of birds. Additional tests on axes of rate variation show rapid changes in microchromosomes immediately after the Cretaceous–Palaeogene transition. These apparent pulses of evolution are consistent with major changes in the genetic machineries for meiosis, heart performance, and RNA splicing, surveillance and translation, and correlate with the ecological diversity reflected in increased tarsus length. Collectively, our analyses paint a nuanced picture of avian evolution, revealing that the ancestors of the most diverse lineages of birds underwent major genomic changes related to mutation, gene usage and niche expansion in the early Palaeogene period.

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Free pdf:

Valentina Rossi, Tiffany Slater, Richard Unitt, Beatriz Carazo del Hoyo, Edoardo Terranova, Mario Gaeta, Maria E. McNamara, Raffaele Sardella & Dawid A. Iurino (2025)
Fossil feathers from the Colli Albani volcanic complex (Late Pleistocene, Central Italy) preserved in zeolites
Geology (advance online publication)
DOI: https://doi.org/10.1130/G52971.1
https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G52971.1/653118/Fossil-feathers-from-the-Colli-Albani-volcanic

Fossil feathers are usually preserved as carbonaceous films and impressions in lacustrine and marine sediments, or embedded in amber, but rarely mineralized. We report mineralized plumage of a griffon vulture preserved in an ash-rich pyroclastic deposit from the Late Pleistocene Colli Albani volcanic complex (Rome, Italy). Feathers are preserved in three dimensions, with preservation of tissue ultrastructures such as melanosomes and the surrounding feather cortex. These tissue ultrastructures are mineralized in nanocrystalline zeolite, a mode of preservation not previously reported in fossil soft tissues. We propose that zeolitization of the host rock promoted the precipitation of nanocrystalline zeolite within feather structures, possibly controlled by local pH conditions (i.e., within the immediate vicinity of the carcass) and the presence of Si-Al-rich fluids during early diagenesis. Our study suggests that terrestrial volcanic settings have the potential for remarkably high fidelity preservation of soft tissue ultrastructure in diverse ancient organisms.

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Free pdf:

Joanne H. Cooper, Nigel J. Collar, Abdeljalil Bouzouggar, Nick Barton & Louise Humphrey (2025)
Late Pleistocene Great Bustards Otis tarda from the Maghreb, eastern Morocco
Ibis (advance online publication)
doi: https://doi.org/10.1111/ibi.13404
https://onlinelibrary.wiley.com/doi/10.1111/ibi.13404

Free pdf:
https://onlinelibrary.wiley.com/doi/epdf/10.1111/ibi.13404


The Moroccan population of the globally endangered Great Bustard Otis tarda is close to extinction. Although it is genetically distinct from the Iberian population, no evidence has been previously available to establish the age of its presence in Morocco. A radiocarbon-dated assemblage of Great Bustards from the cemetery cave at Taforalt now confirms the species as a breeding resident of the Maghreb during the Late Pleistocene, ca. 14 700 years before the present. Furthermore, the remains reveal these birds to have been the subject of human exploitation and ritual behaviours. Recognition of the species' ancient status in Morocco reinforces the importance of this isolated and declining population and may help to add impetus to existing conservation efforts.

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