Body and limb size dissociation at the origin of birds: uncoupling allometric constraints across a macroevolutionary transition
Open accessAbstract
The origin of birds and powered flight is a classic major evolutionary transition. Research on their origin often focuses on the evolution of the wing with trends of forelimb elongation traced back through many nonavian maniraptoran dinosaurs. We present evidence that the relative forelimb elongation within avian antecedents is primarily due to allometry and is instead driven by a reduction in body size. Once body size is factored out, there is no trend of increasing forelimb length until the origin of birds. We report that early birds and nonavian theropods have significantly different scaling relationships within the forelimb and hindlimb skeleton. Ancestral forelimb and hindlimb allometric scaling to body size is rapidly decoupled at the origin of birds, when wings significantly elongate, by evolving a positive allometric relationship with body size from an ancestrally negative allometric pattern and legs significantly shorten by keeping a similar, near isometric relationship but with a reduced intercept. These results have implications for the evolution of powered flight and early diversification of birds. They suggest that their limb lengths first had to be dissociated from general body size scaling before expanding to the wide range of fore and hindlimb shapes and sizes present in today's birds.
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At Pennaraptora and Paraves, there is a notable reduction in body size.
“This coincides with a notable reduction in body size [3, 41, 73, 78, 79]”
From Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds (2020) · cites this paper as [79]
The Phylogenetic Reconstructions section reports a strong signal of body-size reduction within Coelurosauria and reconstructs a small body size at node Paraves. It does not specifically identify a reduction at Pennaraptora, so the claim’s placement at both named groups is only partly supported. (LLM, conf=0.82)
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Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds
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Self-citation
- Authors
- Dececchi, T. A., & Larsson, H. C. E.
- Affiliations
- University of South Dakota (US)
- McGill University (CA)
- Corresponding author
- Dececchi, T. Alexander
- Venue
- Evolution
- Publisher
- Oxford University Press (OUP)
- Published
- 2013-05-28
- Volume
- 67
- Issue
- 9
- Pages
- 2741-2752
- ISSN
- 0014-3820 (ISSN-L)
- OpenAlex
- W1805585697
- Cited by
- 114
- References
- 78
- Citations by year
- 2026: 6 · 2025: 5 · 2024: 3 · 2023: 8 · 2022: 5 · 2021: 14 · 2020: 12 · 2019: 7 · 2018: 14 · 2017: 7 · 2016: 15 · 2015: 7 · 2014: 11
- FWCI
- 7.45
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Evolution (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Evolutionary Biology
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Evolution and Paleontology Studies
- Physical Sciences › Mathematics › Geometry and Topology › Morphological variations and asymmetry
- Keywords
- origin of birds, powered flight, allometry, body size, hindlimb length, early birds
- MeSH terms
- Animals, Birds, Wings, Animal, Evolution, Molecular, Body Size, Genetic Speciation
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