Tip dating supports novel resolutions of controversial relationships among early mammals
| Autor: | Robin M. D. Beck, Benedict King |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Bayesian probability Mandible Biology 010603 evolutionary biology 01 natural sciences Bayesian General Biochemistry Genetics and Molecular Biology 03 medical and health sciences Animals Juramaia Phylogeny 030304 developmental biology General Environmental Science mammaliaforms Estimation Mammals 0303 health sciences General Immunology and Microbiology Eutheria Fossils Bayes Theorem General Medicine Evolution of mammals biology.organism_classification Biological Evolution Biota Haramiyida Taxon Evolutionary biology Palaeobiology Key (cryptography) General Agricultural and Biological Sciences Allotheria Research Article |
| Zdroj: | Proceedings of the Royal Society B: Biological Sciences |
| ISSN: | 1471-2954 0962-8452 |
| Popis: | The estimation of the timing of major divergences in early mammal evolution is challenging owing to conflicting interpretations of key fossil taxa. One contentious group is Haramiyida, the earliest members of which are from the Late Triassic. Many phylogenetic analyses have placed haramiyidans in a clade with multituberculates within crown Mammalia, thus extending the minimum divergence date for the crown group deep into the Triassic. A second taxon of interest is the eutherian Juramaia from the Middle–Late Jurassic Yanliao Biota, which is morphologically very similar to eutherians from the Early Cretaceous Jehol Biota and implies a very early origin for therian mammals. Here, we apply Bayesian tip-dated phylogenetic methods to investigate these issues. Tip dating firmly rejects a monophyletic Allotheria (multituberculates and haramiyidans), which are split into three separate clades, a result not found in any previous analysis. Most notably, the Late Triassic Haramiyavia and Thomasia are separate from the Middle Jurassic euharamiyidans. We also test whether the Middle–Late Jurassic age of Juramaia is ‘expected’ given its known morphology by assigning an age prior without hard bounds. Strikingly, this analysis supports an Early Cretaceous age for Juramaia , but similar analyses on 12 other mammaliaforms from the Yanliao Biota return the correct, Jurassic age. Our results show that analyses incorporating stratigraphic data can produce results very different from other methods. Early mammal evolution may have involved multiple instances of convergent morphological evolution (e.g. in the dentition), and tip dating may be a method uniquely suitable to recognizing this owing to the incorporation of stratigraphic data. Our results also confirm that Juramaia is anomalous in exhibiting a much more derived morphology than expected given its age, which in turn implies very high rates of evolution at the base of therian mammals. |
| Databáze: | OpenAIRE |
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