Biology subjects

Navalon, G.

Publications and source records attributed to Navalon, G..

6 recordsLinked to original sources

bioRxiv2026

Macroevolutionary shifts in post-hatching ontogeny and the origin of craniofacial disparity in fowl (Aves: Galloanserae)

Anseriformes (waterfowl) and Galliformes (landfowl) are among the worlds most recognisable groups of birds, together comprising the clade Galloanserae. Despite their close evolutionary relationship, the skulls of adult anseriforms and galliforms exhibit strikingly distinct morphologies, the developmental basis and evolutionary history of which is poorly understood. To illuminate the developmental and evolutionary underpinnings of cranial disparity between and within these major extant bird clades, we quantitatively investigated ontogenetic changes in cranial morphology across galloanseran phylogenetic diversity, focusing on the previously unexplored post-hatching interval during which adult morphology takes shape. Our results reveal the combined effects of multiple heterochronic shifts early in galloanseran evolutionary history including anseriform hypermorphosis, along with influential non-heterochronic changes leading to substantially more disparate ontogenetic trajectories--and greater cranial variability--in anseriforms than galliforms. Key galloanseran fossils help clarify the polarity of evolutionary shifts in cranial development through galloanseran phylogenetic history and demonstrate that extant galliform cranial morphology is more constrained and retains a more plesiomorphic morphology than that of anseriforms. Our work helps illuminate the developmental basis of the iconic differences in cranial form between waterfowl and landfowl and illustrates the importance of broad phylogenetic and ontogenetic sampling for clarifying patterns of post-hatching developmental divergence among major vertebrate clades.

evolutionary biology↗

bioRxiv2025

Developmental underpinnings of morphological disparity in the avian bony palate

The deepest phylogenetic divergence in crown birds gave rise to Palaeognathae and Neognathae, clades exhibiting divergent bony palate morphologies. This observation led to the longstanding hypothesis that the distinctive palate arrangement of palaeognaths retains the ancestral crown bird condition, but recent fossil evidence instead suggests that aspects of palaeognath palate morphology are derived from a neognath-like ancestral condition. While neoteny has been hypothesised as a mechanism underpinning the distinctive palatal morphologies of palaeognaths, this hypothesis has never been tested with a broad phylogenetic assessment of morphological variation through avian palate ontogeny. Here, we quantitatively assess morphological variation of the palate through the post-hatching ontogenies of 70 bird species representing all major extant phylogenetic subclades, clarifying the ontogenetic mechanisms giving rise to avian palate disparity. Though palaeognaths exhibit distinct ontogenetic changes in the PPC relative to neognaths, we find no signatures of heterochrony--including neoteny--underlying these developmental differences. However, important patterns of morphological change in the avian palate appear to be dictated by variation in developmental mode. Our results document the effects of post-hatching development on a key morphofunctional system in the avian skull, and, more broadly, highlight the influence of developmental mode on morphological evolvability across crown group birds.

evolutionary biology↗

bioRxiv2025

Shouldering the challenge of deciphering avian palate evolution

Wilken et al. (1) investigate the evolution of avian palatal kinesis using comparative morphology and biomechanical modelling. While the studys topic and approach are timely, its conclusions are marred by inadequate taxon sampling and morphological misinterpretations.

evolutionary biology↗

bioRxiv2023

Geographic patterns of living tetrapod diversity reveal the signature of global diversification dynamics

AimBiodiversity is distributed unevenly among lineages and regions, and understanding the processes generating these global patterns is a central goal in evolutionary research, particularly in light of the current biodiversity crisis. Here, we integrate phylogenetic relatedness with species diversity patterns in four major clades of living tetrapods (amphibians, squamates, birds, and mammals) to approach this challenge. LocationGlobal. Time period300 million years ago - Present. Major taxa studiedTetrapods. MethodsWe studied geographic patterns of richness-corrected phylogenetic diversity (residual PD), identifying regions where species are phylogenetically more closely or distantly related than expected by richness. We explored the effect of different factors in residual PD: recent speciation rates, temporal trends of lineage accumulation, and environmental variables. Specifically, we searched for evolutionary and ecological differences between regions of high and low residual PD. ResultsOur results show heterogeneous spatial patterns of diversity dynamics across tetrapods. They reveal an overall negative relationship between recent speciation rates and residual PD, underscoring the role of recent speciation events in structuring current biogeographic patterns. Furthermore, we found differences between endothermic and ectothermic tetrapods in response to temperature and precipitation, highlighting the pivotal role of thermal physiology in shaping diversity dynamics. Main conclusionsGeographic patterns of diversity dynamics are heterogeneous across tetrapod clades and help us disentangle the evolutionary and ecological processes underlying them. By illuminating the multifaceted factors underpinning global diversity patterns, our study represents a significant advancement towards better understanding of how the present-day diversity of tetrapods was formed and how speciation rates influenced their species and phylogenetic diversity across clades and regions.

evolutionary biology↗

bioRxiv2023

Macroevolutionary drivers of morphological disparity in the avian quadrate

In birds, the quadrate bone acts as a hinge between the lower jaw and the skull, playing an important role in cranial kinesis. As such, the evolution of avian quadrate morphology may plausibly be assumed to have been influenced by selective pressures related to feeding ecology. However, variation in quadrate morphology across living birds and its potential relationship with ecology have never been quantitatively characterised. Here, we used three-dimensional geometric morphometrics and phylogenetic comparative methods to quantify morphological variation of the quadrate and its relationship with an array of key ecological features across 200 bird species covering all major extant lineages. We found non-significant associations between quadrate shape and several aspects of feeding and foraging ecology across different scales of phylogenetic comparison. By contrast, allometry and phylogeny exhibit stronger relationships with quadrate shape than other ecological features. We show that the avian quadrate evolves as an integrated unit and exhibits strong associations with the morphologies of neighbouring bones. Our results collectively suggest a macroevolutionary scenario in which the shape of the quadrate evolved jointly with other elements of the avian kinetic system, with the major lineages of birds exploring alternative quadrate morphologies--highlighting the potential diagnostic value of quadrate morphology in investigations of fossil bird systematics.

paleontology↗

bioRxiv2022

Sinking a giant: quantitative macroevolutionary comparative methods debunk qualitative assumptions

Myhrvold et al.1 suggest that our inference of subaqueous foraging among spinosaurids2 is undermined by selective bone sampling, inadequate statistical procedures, and use of inaccurate ecological categorizations. Myhrvold et al.1 ignore major details of our analyses and results, and instead choose to portray our inferences as if they were based on qualitative interpretations of our plots, without providing additional analyses to support their claims. In this manuscript, we thoroughly discuss all the concerns exposed by Myhrvold et al.1. Additional analyses based on our original datasets2 and novel data presented by Myhrvold et al.1 do not change our original interpretations: while the spinosaurid dinosaurs Spinosaurus and Baryonyx are recovered as subaqueous foragers, Suchomimus is inferred as a non-diving animal.

paleontology↗