Palaeognath bony palate morphology + bird track assemblage from Miocene of Argentina + mammal anterior dentition function (free pdfs)

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

Some recent non-dino papers:

Free pdf:

Olivia Plateau, Guillermo Navalón, Juan Benito & Daniel J. Field (2026)
Developmental underpinnings of morphological disparity in the avian bony palate
Nature Communications (advance online publication)
doi: https://doi.org/10.1038/s41467-026-69576-w
https://www.nature.com/articles/s41467-026-69576-w


[We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.]

The bony palate of palaeognaths was long thought to retain the plesiomorphic condition for crown birds, but recent fossil evidence suggests that aspects of palaeognath palate morphology are derived from a neognath-like ancestral state. Relatedly, heterochronic shifts have been proposed as the mechanism underpinning major evolutionary transitions in avian palate morphology, but this hypothesis has never been explicitly tested with a broad phylogenetic assessment of morphological variation through avian ontogeny. Here, we assess palatal changes through post-hatching ontogeny across the major extant avian subclades and find that although palaeognaths exhibit distinct ontogenetic changes relative to neognaths, no signatures of heterochrony underlie these developmental differences. However, we find that important patterns of morphological change appear to be dictated by variation in developmental mode. Our results clarify the ontogenetic mechanisms driving avian palate disparity and illustrate the influence of developmental mode on the evolvability of a key morphofunctional system in the avian skull.

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Free pdf:

Martin E. Farina, Verónica Krapovickas, and Claudia A. Marsicano (2026)
Ichnotaxonomy and paleobiology of a bird track assemblage from the Miocene Vinchina Formation of La Rioja Province, Argentina
Acta Palaeontologica Polonica 71(1): 29-50
doi:10.4202/app.01284.2025
https://www.app.pan.pl/article/item/app012842025.html

Free pdf:
https://www.app.pan.pl/archive/published/app71/app012842025.pdf


This study examines the bird ichnoassemblage of the Miocene Vinchina Formation (La Rioja Province, Argentina), recorded in fluvio-lacustrine environments. Both unpublished material and previously collected specimens were analysed across three transverse sections cropping out from north to south in the Quebrada Pedregal Negro, the Quebrada de la Troya, and the Quebrada del Yeso. The Pedregal Negro creek has yielded only Aviadactyla vialovi, recently synonymised with Ornithotarnocia lambrechti. The low ichnodiversity observed is likely due more to limited exploration efforts and poor outcrop exposure in the creek than to palaeoenvironmental constraints. Exposures at Quebrada de la Troya yield six ichnotaxa preserved in fluvial and lacustrine settings: Aramayoichnus rheae (a large rheid and the oldest rheid track in southern South America), Phoenicopterichnus rector (Phoenicopteridae), Ardeipeda isp. (Ciconiiformes), cf. Jindonornipes, cf. Aquatilavipes (small aquatic birds, possibly Recurvirostridae or Charadriidae), and Rionegrina isp. (a functional didactyl phorusrhacid). At Quebrada del Yeso creek, five ichnospecies of birds were recognised and preserved in a playa-lake environment: Phoenicopterichnus rector, Gragliavipes gavenskii (Threskiornithidae), Avipeda isp. (likely Scolopacidae or Charadriidae), together with a ralliform morphotype and a Cariamidae morphotype. Overall, the trackmakers represented in the three ichnoassemblages correspond well with the globally known Miocene avian body fossil record. While the Pedregal Negro section warrants further exploration, differences in ichnodiversity between Quebrada del Yeso and Quebrada de la Troya likely reflect ecological factors, as the track-bearing levels in the latter represent environments with greater freshwater availability, which may have supported more diverse bird communities.

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Free pdf:

Wighart von Koenigswald (2026)
Diversity and function of the anterior dentitions in fossil and extant mammals
Palaeobiodiversity and Palaeoenvironments (advance online publication)
doi: https://doi.org/10.1007/s12549-025-00690-1
https://link.springer.com/article/10.1007/s12549-025-00690-1


This paper reviews the morphological diversity of the anterior dentition (AD - incisors and canines) in fossil and extant mammals. The great diversity of the mammalian anterior dentition is due to mosaic evolution of different morphological features. The paper identifies twenty-one groups of genera that share specific features but are not phylogenetically related. These groups are referred to as clusters. Minor differences within the clusters are described as modifications that are found in the different mammalian orders. The clusters highlight convergent features as well as evolutionary trends that occur in different clusters, such as the reduction of antemolars, the formation of incisiform lower canines and of caniniform lower premolars. The different functions of the anterior teeth within these clusters are discussed. They suggest that adaptations for quite different functions have led to very similar structures. During evolution, the reduction of anterior teeth is rare in carnivores but common in herbivores. This illustrates the increasing importance of soft parts, such as lips, tongue and trunk for foraging. The setup of the clusters described here is not intended as an additional system to which taxa must be assigned, but as a framework for highlighting similarities in unrelated taxa.

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