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Updated: Oct 17, 2025
07:34
Probing the Limits of Egg Recognition Using Egg Rejection Experiments Along Phenotypic Gradients
Published on: August 22, 2018
8.4K
Parsimony-based test for identifying changes in evolutionary trends for quantitative characters: implications for the
Gilles Didier1,2, Olivier Chabrol2, Michel Laurin3
1IMAG, Univ Montpellier, CNRS, Montpellier, France.
Summary
The origin of the amniotic egg, a key event in vertebrate evolution, is explored. A new parsimony method refutes Carroll's 1970 scenario by finding no distinct body size trend shifts in stem-amniotes.
Area of Science:
- Evolutionary Biology
- Paleontology
- Phylogenetics
Background:
- The amniotic egg's origin was crucial for amniote radiation.
- Carroll's 1970 scenario proposes distinct evolutionary trends for its origin.
Purpose of the Study:
- To test Carroll's 1970 scenario for amniotic egg origin.
- To apply a novel asymmetric linear parsimony method.
Main Methods:
- Utilized an asymmetric linear parsimony method to find the most parsimonious tree splits.
- Evaluated character evolution costs across phylogenetic tree nodes.
- Analyzed body size trends in Permo-Carboniferous stegocephalians.
Main Results:
- Identified 517 parsimonious trend changes in Permo-Carboniferous stegocephalians.
- Found only one trend change in the stem-amniote lineage, contradicting Carroll's prediction.
- Nodal body size estimates did not strongly support Carroll's scenario.
Conclusions:
- Carroll's 1970 scenario for amniotic egg origin is refuted.
- The amniote stem shows no elevated rates of evolutionary trend shifts.
- The novel parsimony method provides a new approach for phylogenetic analysis.
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