Disparity of cycad leaves dispels the living fossil metaphor
- Author(s)
- Mario Coiro, Leyla Jean Seyfullah
- Abstract
The living fossil metaphor is tightly linked with the cycads. This group of gymnosperms is supposed to be characterised by long-term morphological stasis, particularly after their peak of diversity and disparity in the Jurassic. However, no formal test of this hypothesis exists. Here, we use a recent phylogenetic framework and an improved character matrix to reconstruct the Disparity Through Time for cycad leaves using a Principal Coordinate Analysis and employing Pre-Ordination Ancestral State Reconstruction to test the impact of sampling on the results. Our analysis shows that the cycad leaf morsphospace expanded up to the present, with numerous shifts in its general positioning, independently of sampling biases. Moreover, they also show that Zamiaceae expanded rapidly in the Early Cretaceous and continued to expand up to the present, while now-extinct clades experienced a slow contraction from their peak in the Triassic. We also show that rates of evolution were constantly high up to the Early Cretaceous, and then experienced a slight decrease in the Paleogene, followed by a Neogene acceleration. These results show a much more dynamic history for cycads, and suggest that the 'living fossil' metaphor is actually a hindrance to our understanding of their macroevolution.
- Organisation(s)
- Department of Palaeontology
- External organisation(s)
- Ronin Institute for Independent Scholarship, Montclair, NJ, 07043, USA.
- Journal
- Communications Biology
- Volume
- 7
- Pages
- 328
- ISSN
- 2399-3642
- DOI
- https://doi.org/10.1038/s42003-024-06024-9
- Publication date
- 12-2024
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105117 Palaeobotany, 106012 Evolutionary research, 106042 Systematic botany
- Keywords
- ASJC Scopus subject areas
- Agricultural and Biological Sciences(all), Biochemistry, Genetics and Molecular Biology(all), Medicine (miscellaneous)
- Sustainable Development Goals
- SDG 15 - Life on Land
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/disparity-of-cycad-leaves-dispels-the-living-fossil-metaphor(9e747cce-e8a9-4806-8461-534f7ec03c60).html