Aeviperditus, new "bowerbird" from Miocene of New Zealand + evolution of bird limb skeleton proportion + Galloanseran cranial development + more
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Ben Creisler
Oct 8, 2025, 3:06:23 PM (11 days ago) Oct 8
to DinosaurMa...@googlegroups.com
Ben Creisler
Some recent avian papers:
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Free pdf:
Aeviperditus gracilis gen. et sp. nov.
Elizabeth M. Steell, Daniel J. Field, Pascale Lubbe, Alex Brown, Nicolas J. Rawlence & Alan J.D. Tennyson (2025)
A possible early bowerbird from the Miocene of New Zealand
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2025.2568099
https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2568099
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/08912963.2025.2568099
ZooBank publication LSID
urn:lsid:http://www.zoobank.org/zoobank.org:pub:2991625B-E79E-4DE7-BD8C-67685CC58693
Aotearoa New Zealand is home to several endemic passerine bird lineages that likely dispersed from Australia between the Eocene and Miocene. Although the Australian pre-Pleistocene passerine fossil record is well-described, comparatively little is known about Miocene passerines from New Zealand. Here, we describe a distinctive tarsometatarsus attributable to a new passerine species, Aeviperditus gracilis gen. et sp. nov. from the Miocene locality St Bathans, New Zealand, which exhibits derived similarities with bowerbirds (Ptilonorhynchidae). This species, tentatively referred to total-group Ptilonorhynchidae, appears to represent a previously unknown passerine lineage for New Zealand and may drastically alter the prehistoric geographic distribution of bowerbirds, which are presently known from Australia and New Guinea. Trait-based similarity analysis shows the tarsometatarsus of A. gracilis is most comparable to the ‘avenue builder’ subclade of crown Ptilonorhynchidae. However, its diminutiveness and elongate proportions are unlike those of extant and fossil bowerbirds. Aeviperditus gracilis may represent a stem ptilonorhynchid, whereby similarities to extant bowerbirds are most likely plesiomorphic; however, additional, more complete fossils are required to clarify its phylogenetic position. Surviving endemic passerine lineages in New Zealand may represent the relicts of a once-diverse passerine avifauna, with the extinction of species like A. gracilis potentially associated with climatic cooling.
urn:lsid:http://www.zoobank.org/zoobank.org:pub:2991625B-E79E-4DE7-BD8C-67685CC58693
Aotearoa New Zealand is home to several endemic passerine bird lineages that likely dispersed from Australia between the Eocene and Miocene. Although the Australian pre-Pleistocene passerine fossil record is well-described, comparatively little is known about Miocene passerines from New Zealand. Here, we describe a distinctive tarsometatarsus attributable to a new passerine species, Aeviperditus gracilis gen. et sp. nov. from the Miocene locality St Bathans, New Zealand, which exhibits derived similarities with bowerbirds (Ptilonorhynchidae). This species, tentatively referred to total-group Ptilonorhynchidae, appears to represent a previously unknown passerine lineage for New Zealand and may drastically alter the prehistoric geographic distribution of bowerbirds, which are presently known from Australia and New Guinea. Trait-based similarity analysis shows the tarsometatarsus of A. gracilis is most comparable to the ‘avenue builder’ subclade of crown Ptilonorhynchidae. However, its diminutiveness and elongate proportions are unlike those of extant and fossil bowerbirds. Aeviperditus gracilis may represent a stem ptilonorhynchid, whereby similarities to extant bowerbirds are most likely plesiomorphic; however, additional, more complete fossils are required to clarify its phylogenetic position. Surviving endemic passerine lineages in New Zealand may represent the relicts of a once-diverse passerine avifauna, with the extinction of species like A. gracilis potentially associated with climatic cooling.
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Free pdf:
Abi H. Crane, Juan Benito, Albert Chen, Daniel T. Ksepka & Daniel J. Field (2025)
Mandibular morphology clarifies phylogenetic relationships near the origin of crown birds
bioRxiv 2025.09.26.678747 (preprint)
doi: https://doi.org/10.1101/2025.09.26.678747
https://www.biorxiv.org/content/10.1101/2025.09.26.678747v1
Background: The phylogenetic relationships of fossil birds near the origin of the avian crown group remain debated, in part due to a limited amount of character evidence from incomplete fossils. The avian lower jaw provides a potentially rich source of additional character data, yet fusion of the individual bony elements composing the avian post-dentary complex has impeded efforts to explore its phylogenetic signal. Here, we use high-resolution µCT-scanning to separate the individual bony elements of the mandibles of several immature crown birds and key fossil taxa, and use those data to assess support for alternative phylogenetic hypotheses for fossils near the origin of crown birds.
Results: We find that evidence from Asteriornis fails to support interpretations of derived mandibular similarities with palaeognaths, and instead strongly favours galloanseran, and specifically galliform, affinities. Our results also illustrate striking similarities in the architecture of the lower jaws between the toothed ornithurine Ichthyornis, Pelagornithidae and Vegavis, which, in addition to the absence of derived features linking them to Galloanserae, highlights questions regarding the phylogenetic position of these perennially controversial taxa.
Conclusions: Our data reveal new insight into patterns of morphological evolution near the origin of the avian crown group while raising new phylogenetic questions, emphasising the potential untapped value of detailed comparative investigations of morphological complexes such as the post-dentary complex of the mandible for informing the early evolutionary history of crown birds.
Mandibular morphology clarifies phylogenetic relationships near the origin of crown birds
bioRxiv 2025.09.26.678747 (preprint)
doi: https://doi.org/10.1101/2025.09.26.678747
https://www.biorxiv.org/content/10.1101/2025.09.26.678747v1
Background: The phylogenetic relationships of fossil birds near the origin of the avian crown group remain debated, in part due to a limited amount of character evidence from incomplete fossils. The avian lower jaw provides a potentially rich source of additional character data, yet fusion of the individual bony elements composing the avian post-dentary complex has impeded efforts to explore its phylogenetic signal. Here, we use high-resolution µCT-scanning to separate the individual bony elements of the mandibles of several immature crown birds and key fossil taxa, and use those data to assess support for alternative phylogenetic hypotheses for fossils near the origin of crown birds.
Results: We find that evidence from Asteriornis fails to support interpretations of derived mandibular similarities with palaeognaths, and instead strongly favours galloanseran, and specifically galliform, affinities. Our results also illustrate striking similarities in the architecture of the lower jaws between the toothed ornithurine Ichthyornis, Pelagornithidae and Vegavis, which, in addition to the absence of derived features linking them to Galloanserae, highlights questions regarding the phylogenetic position of these perennially controversial taxa.
Conclusions: Our data reveal new insight into patterns of morphological evolution near the origin of the avian crown group while raising new phylogenetic questions, emphasising the potential untapped value of detailed comparative investigations of morphological complexes such as the post-dentary complex of the mandible for informing the early evolutionary history of crown birds.
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Free pdf:
Andrew Orkney, Priscila S. Rothier and Brandon P. Hedrick (2025)
Great expectations: altricial developmental strategies are associated with more flexible evolution of limb skeleton proportions in birds
Proceedings of the Royal Society B: Biological Sciences 292(2056): 20251647
doi: https://doi.org/10.1098/rspb.2025.1647
https://royalsocietypublishing.org/doi/10.1098/rspb.2025.1647
Free pdf:
https://royalsocietypublishing.org/doi/epdf/10.1098/rspb.2025.1647
Birds have repeatedly evolved diverse developmental strategies, including multiple origins of sophisticated parental care, making them a model system to explore the consequences of developmental strategy upon phenotypic evolution. Here, we assess evolutionary covariance between limb proportions and ecological diversity of different bird lineages with altricial (high parental care) or precocial (lower parental care) developmental strategies. In addition, we model overall rates of evolutionary divergence between wing and leg skeletal proportions, allowing us to investigate the influence of developmental strategy upon adaptive traits. We show that while wing and leg proportions evolve independently of one another in altricial lineages, conforming to a modular pattern of evolution attested in birds more generally, there are strong correlations between wing and leg trait evolution in precocial lineages. Unlike precocial groups, divergent wing and leg evolution in altricial lineages is associated with access to novel flight-style combinations and is strongly associated with body mass. This suggests an adaptive association with mechanisms of growth and development. Inspection of internal wing proportions within major clades demonstrates that lineages with more altricial developmental strategies explore a wider range of mechanically relevant wing proportions, such as Brachial Index.
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Free pdf:
Bassel Arnaout, Kaylen Brzezinski, Albert Chen, Benjamin Steventon & Daniel J. Field (2025)
Galloanseran cranial development highlights exceptions to von Baer’s laws
EvoDevo 16: 17
doi: https://doi.org/10.1186/s13227-025-00253-7
https://evodevojournal.biomedcentral.com/articles/10.1186/s13227-025-00253-7
The remarkable morphological disparity of the animal kingdom is underpinned by changes in embryonic development across the tree of life; as such, deciphering evolutionary patterns of developmental divergence depends on investigations of different species across a range of comparable developmental stages. Among the most influential ideas regarding such developmental divergences are von Baer’s Laws of Development and Haeckel’s Theory of Recapitulation. Here, we assess several predictions following from these ideas at the tissue-level by comparing skull osteogenesis in representatives of the bird clade Galloanserae. We investigated high-resolution µCT scans of embryonic series for four galloanseran species: chickens and quails, representing Galliformes (landfowl), and ducks and geese, representing Anseriformes (waterfowl). To compare skull osteogenesis across our taxon sample, we devised a skull-specific staging system based on ossification sequences to discretise the process into five stages. During skull osteogenesis, we found that the location of the onset of ossification within each element and the direction of ossification progression were the same in all species in our sample, implying a conserved developmental programme for induction and ossification progression across Galloanserae. Moreover, we found that the appearance of synapomorphies diagnostic of broader clades often overlapped with species-specific ones during osteogenesis. Indeed, many diagnostic features of deep clades, such as osteological synapomorphies of the phylogenetically inclusive clade Galloanserae, appear at surprisingly late stages of development. These observations fail to support several predictions of von Baer’s Laws of Development and Haeckel’s Theory of Recapitulation, instead suggesting what we term a ‘braiding’ pattern of developmental divergence in which degrees of interspecific morphological similarity wax and wane during development as a result of the interplay between developmental constraints and phyletic variation.
Bassel Arnaout, Kaylen Brzezinski, Albert Chen, Benjamin Steventon & Daniel J. Field (2025)
Galloanseran cranial development highlights exceptions to von Baer’s laws
EvoDevo 16: 17
doi: https://doi.org/10.1186/s13227-025-00253-7
https://evodevojournal.biomedcentral.com/articles/10.1186/s13227-025-00253-7
The remarkable morphological disparity of the animal kingdom is underpinned by changes in embryonic development across the tree of life; as such, deciphering evolutionary patterns of developmental divergence depends on investigations of different species across a range of comparable developmental stages. Among the most influential ideas regarding such developmental divergences are von Baer’s Laws of Development and Haeckel’s Theory of Recapitulation. Here, we assess several predictions following from these ideas at the tissue-level by comparing skull osteogenesis in representatives of the bird clade Galloanserae. We investigated high-resolution µCT scans of embryonic series for four galloanseran species: chickens and quails, representing Galliformes (landfowl), and ducks and geese, representing Anseriformes (waterfowl). To compare skull osteogenesis across our taxon sample, we devised a skull-specific staging system based on ossification sequences to discretise the process into five stages. During skull osteogenesis, we found that the location of the onset of ossification within each element and the direction of ossification progression were the same in all species in our sample, implying a conserved developmental programme for induction and ossification progression across Galloanserae. Moreover, we found that the appearance of synapomorphies diagnostic of broader clades often overlapped with species-specific ones during osteogenesis. Indeed, many diagnostic features of deep clades, such as osteological synapomorphies of the phylogenetically inclusive clade Galloanserae, appear at surprisingly late stages of development. These observations fail to support several predictions of von Baer’s Laws of Development and Haeckel’s Theory of Recapitulation, instead suggesting what we term a ‘braiding’ pattern of developmental divergence in which degrees of interspecific morphological similarity wax and wane during development as a result of the interplay between developmental constraints and phyletic variation.
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Free pdf:
E. Yagmur Erten, Marc Tollis & Hanna Kokko (2025)
Shrinking to bird size with dinosaur-level cancer defences: Evolution of cancer suppression over macroevolutionary time.
PLoS Computational Biology 21(9): e1013432
doi: https://doi.org/10.1371/journal.pcbi.1013432
https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1013432
Abstract
Ubiquity of cancer across the tree of life yields opportunities to understand variation in cancer defences across species. Peto’s paradox, the finding that large-bodied species do not suffer from more cancer despite having more cells at risk of oncogenic mutations compared to small species, can be explained if large size selects for better cancer defences. Since birds live longer than non-flying mammals of equivalent size, and are descendants of moderate-sized dinosaurs, we ask whether ancestral cancer defences are retained if body size shrinks in a lineage. Our model derives selection coefficients and fixation events for changes in cancer defences over macroevolutionary time, based on known relationships between body size, cancer risk, extrinsic mortality, metabolic rate, and effective population size. We show that, if mutation rate is sufficiently high and cancer defences are costly, we expect birds to have lower cancer defences than their dinosaurian ancestors. However, if the evolution of cancer suppression is mutation limited, due to e.g. pleiotropy, birds may have kept excessive dinosaurian cancer defences, possibly explaining their low cancer risk. Counterintuitively, birds can then be ‘too robust’ for their own good, if excessive cancer suppression requires compromising reproductive rates. Yet, evolutionary innovations such as flight can increase longevity and keep selection for cancer suppression intact in birds, even if flight requires small body size. Retaining dinosaur-level cancer defences can then be adaptive, particularly if the evolution of flight is accompanied by an increase in cancer risk due to metabolic scaling. Overall, our study suggests that studying cancer suppression in birds can reveal alternative mechanisms to those found in mammals, possibly inherited from birds’ dinosaurian ancestors.
Author summary
Humans are not the only species suffering from cancer, yet cancer does not impact all life equally. Body size is relevant because maintaining a large number of cells in a tumour-free state necessitates improved cancer defences. Present-day birds appear adept at avoiding cancer, and live longer than similarly sized mammals. Since birds arose from a large-bodied dinosaur lineage rather than having always been small, we ask if evolutionary lags might explain their superior cancer defences. We model the circumstances under which dinosaurian anti-cancer innovations can still persist, making birds more cancer-resistant and longer-lived than mammals. We show that unless the process is mutation-limited, dinosaur-level cancer defences will decay over macroevolutionary time. However, evolutionary lags, when they do occur, can render birds cancer-robust and explain their relatively long lifespans. Eroding defences is made less likely by evolution of flight, which by reducing extrinsic mortality risk can make long lifespans feasible, and by metabolic scaling during shrinkage, if increasing mass-specific metabolic rate translates into an increase in the rate of cancer-causing mutations.
===
E. Yagmur Erten, Marc Tollis & Hanna Kokko (2025)
Shrinking to bird size with dinosaur-level cancer defences: Evolution of cancer suppression over macroevolutionary time.
PLoS Computational Biology 21(9): e1013432
doi: https://doi.org/10.1371/journal.pcbi.1013432
https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1013432
Abstract
Ubiquity of cancer across the tree of life yields opportunities to understand variation in cancer defences across species. Peto’s paradox, the finding that large-bodied species do not suffer from more cancer despite having more cells at risk of oncogenic mutations compared to small species, can be explained if large size selects for better cancer defences. Since birds live longer than non-flying mammals of equivalent size, and are descendants of moderate-sized dinosaurs, we ask whether ancestral cancer defences are retained if body size shrinks in a lineage. Our model derives selection coefficients and fixation events for changes in cancer defences over macroevolutionary time, based on known relationships between body size, cancer risk, extrinsic mortality, metabolic rate, and effective population size. We show that, if mutation rate is sufficiently high and cancer defences are costly, we expect birds to have lower cancer defences than their dinosaurian ancestors. However, if the evolution of cancer suppression is mutation limited, due to e.g. pleiotropy, birds may have kept excessive dinosaurian cancer defences, possibly explaining their low cancer risk. Counterintuitively, birds can then be ‘too robust’ for their own good, if excessive cancer suppression requires compromising reproductive rates. Yet, evolutionary innovations such as flight can increase longevity and keep selection for cancer suppression intact in birds, even if flight requires small body size. Retaining dinosaur-level cancer defences can then be adaptive, particularly if the evolution of flight is accompanied by an increase in cancer risk due to metabolic scaling. Overall, our study suggests that studying cancer suppression in birds can reveal alternative mechanisms to those found in mammals, possibly inherited from birds’ dinosaurian ancestors.
Author summary
Humans are not the only species suffering from cancer, yet cancer does not impact all life equally. Body size is relevant because maintaining a large number of cells in a tumour-free state necessitates improved cancer defences. Present-day birds appear adept at avoiding cancer, and live longer than similarly sized mammals. Since birds arose from a large-bodied dinosaur lineage rather than having always been small, we ask if evolutionary lags might explain their superior cancer defences. We model the circumstances under which dinosaurian anti-cancer innovations can still persist, making birds more cancer-resistant and longer-lived than mammals. We show that unless the process is mutation-limited, dinosaur-level cancer defences will decay over macroevolutionary time. However, evolutionary lags, when they do occur, can render birds cancer-robust and explain their relatively long lifespans. Eroding defences is made less likely by evolution of flight, which by reducing extrinsic mortality risk can make long lifespans feasible, and by metabolic scaling during shrinkage, if increasing mass-specific metabolic rate translates into an increase in the rate of cancer-causing mutations.
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