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Cited by 122Paleontology and Evolutionary BiologyEvolution and Paleontology StudiesAnimal Behavior and Reproduction

The evolution of ‘bizarre structures’ in dinosaurs: Biomechanics, sexual selection, social selection or species recognition?

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Padian, K., Horner, J. R.·2011·Journal of Zoology
DOI 10.1111/j.1469-7998.2010.00719.x
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Abstract

‘Bizarre structures’ in dinosaurs have four main traditional explanations: mechanical function, sexual selection, social selection and species recognition. Any of these can be plausible for individual species, but they fail to be persuasive when other lines of evidence cannot adequately test them. The first three also fail as general propositions when phylogenetic analyses based on other characters do not support scenarios of selective improvement of such functions in their clade (or the explanation simply does not apply to any other species in the clade). Moreover, the hypothesis of sexual selection requires significant sexual dimorphism, which has never been conclusively established in dinosaurs. We propose instead that species recognition may have been a more general force that drove the evolution of bizarre structures in dinosaurs. That is, the bizarre structures communicate to other individuals a variety of possible associational cues, including species identification, potential protection and social habits and the appropriateness of potential mates. In other words, bizarre structures amount to an advertisement for positive association. Neither species recognition nor any other hypothesis should be a ‘default’ explanation. Although direct observation is impossible, we propose two tests. First, contrary to adaptive, social or sexual selection, under the species recognition model morphology should be expected to evolve without obvious directional trends, because the only objective is to differ from one's relatives. Hence, patterns of evolution of bizarre structures should be relatively proliferative and non-directional. Second, several contemporaneous species should overlap in geographic range (sympatric, parapatric, peripatric). Fossil species often show evidence of this pattern in the past by ‘ghost ranges’ of related taxa. These tests together could reinforce or weaken an argument for species recognition.

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  • Reptiles span a wide range of social tendencies, and some have been highly social hundreds of millions of years ago; dinosaurs had complex parental care, communal nesting, and gregarious foraging.

    “They span a wide range of social tendencies, and some of them have been highly social even hundreds of millions of years ago; for example, dinosaurs had complex parental care, communal nesting, and gregarious foraging (see, for example, Horner, 2000; Varicchio et al., 2008; Padian et al., 2011; Fiorillo et al., 2014; Pol et al., 2021).”

    From The evolution of sociality and the polyvagal theory (2023) · cites this paper as Padian et al., 2011

    In “Comparative tests of the mate competition and species recognition hypotheses” (page unavailable), the paper identifies banding together and parental care as possible advantages of species recognition in dinosaurs. It does not establish complex parental care or describe communal nesting or gregarious foraging; nor does it survey the range of social tendencies across reptiles. (LLM, conf=0.82)

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Research works printed but not linked: 9

  1. Chapman, R., Weishampel, D.B., Hunt, G. & Rasskin-Gut- man, D. (1997). Sexual dimorphism in dinosaurs. In Dinofest International: proceedings of a symposium held at Arizona State University: 83-93.
  2. Davitashvili, L.Sh. (1961). Teoriya polovogo otbora [The theory of sexual selection]. Moscow: Izdatel'stvo Akademii Nauk (Academy of Sciences Press).
  3. Schopf, T.J.M. (Ed.). San Francisco: Free- man, Cooper.
  4. Evans, D.C. (2007) Ontogeny and evolution of Lambeosaurine dinosaurs (Ornithischia: Hadrosauridae). PhD thesis, University of Toronto, 497pp.
  5. Larson, P. (1997). The king's new clothes: a fresh look at Tyrannosaurus rex. In Dinofest International: proceedings of a symposium held at Arizona State University: 65-71.
  6. Padian, K. (1982). Macroevolution and the origin of major adaptations: vertebrate flight as a paradigm for the analysis of patterns. Proc. Third N. Am. Paleontol. Convention 2, 387-392.
  7. Rose, M.R. & Lauder, G.V. (Eds). (1996). Adaptation. San Diego: Academic Press.
  8. Scannella, J.B. & Horner, J.R. (in press). Torosaurus Marsh, 1891 is Triceratops Marsh, 1889 (Ceratopsidae: Chasmo- saurinae): synonomy through ontogeny. J. Vertebr. Paleontol.
  9. Weishampel, D.B., Dodson, P. & Osmolska, H. (Eds). (2004). The Dinosauria, 2nd edn. Berkeley: University of Califor- nia Press.

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Authors
Padian, K., & Horner, J. R.
Affiliations
  • University of California, Berkeley (US)
  • Montana State University (US)
Corresponding author
Padian, K.
ORCID
Venue
Journal of Zoology
Publisher
Wiley
Published
2010-12-22
Volume
283
Issue
1
Pages
3-17
ISSN
  • 0952-8369 (ISSN-L)
  • 1469-7998
DOI
10.1111/j.1469-7998.2010.00719.x
OpenAlex
W1524086639
Cited by
122
References
90
Citations by year
2026: 6 · 2025: 7 · 2024: 4 · 2023: 7 · 2022: 3 · 2021: 6 · 2020: 14 · 2019: 6 · 2018: 9 · 2017: 11 · 2016: 8 · 2015: 6 · 2014: 11 · 2013: 10 · 2012: 7
FWCI
5.41
Type
journal article
Language
en
Open access
Licence
Locations
Journal of Zoology (publishedVersion)
Funders
University of California Museum of Paleontology
Topics
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Evolutionary Biology
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Evolution and Paleontology Studies
  • Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Animal Behavior and Reproduction
Keywords
dinosaurs, species recognition, sexual selection, social selection, sexual dimorphism, adaptive evolution, morphological evolution, sympatry, phylogenetic analysis

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