Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals
Adaptive radiations are hypothesised as a generating mechanism for much of the morphological diversity of extant species 1,2,3,4,5,6,7 . The Cenozoic radiation of placental mammals, the foundational example of this concept 8,9 , gave rise to much of the morphological disparity of extant mammals, and...
| Auteurs principaux: | , , , |
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| Format: | Journal article |
| Langue: | English |
| Publié: |
Cell Press
2021
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| _version_ | 1826307673176408064 |
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| author | Brocklehurst, N Panciroli, E Benevento, G Benson, RBJ |
| author_facet | Brocklehurst, N Panciroli, E Benevento, G Benson, RBJ |
| author_sort | Brocklehurst, N |
| collection | OXFORD |
| description | Adaptive radiations are hypothesised as a generating mechanism for much of the
morphological diversity of extant species 1,2,3,4,5,6,7 . The Cenozoic radiation of
placental mammals, the foundational example of this concept 8,9 , gave rise to much
of the morphological disparity of extant mammals, and is generally attributed to relaxed
evolutionary constraints following the extinction of non-avian dinosaurs 10,11,12,13 .
However, study of this and other radiations has focussed on variation in evolutionary
rates 4,5,7,14 , leaving the extent to which relaxation of constraints enabled the origin
of novel phenotypes less well-characterised 15,16,17 . We evaluate constraints on
morphological evolution among mammaliaforms (mammals and their closest relatives)
using a new method that quantifies the capacity of evolutionary change to generate
phenotypic novelty. We find that Mesozoic crown-group therians, which include the
ancestors of placental mammals, were significantly more constrained than other
mammaliaforms. Relaxation of these constraints occurred in the mid-Paleocene, postdating the extinction of non-avian dinosaurs at the K/Pg boundary, instead coinciding
with important environmental shifts and with declining ecomorphological diversity in
non-theriimorph mammaliaforms. This relaxation occurred even in small-bodied
Cenozoic mammals weighing <100g, which are unlikely to have competed with
dinosaurs. Instead, our findings support a more complex model whereby Mesozoic
crown therian evolution was in-part constrained by co-occurrence with disparate
mammaliaforms, as well as by presence of dinosaurs, within-lineage incumbency
effects and environmental factors. Our results demonstrate that variation in
evolutionary constraints can occur independently of variation in evolutionary rate; and
that both make important contributions to the understanding of adaptive radiations. |
| first_indexed | 2024-03-07T07:08:16Z |
| format | Journal article |
| id | oxford-uuid:bda82407-db76-4c15-b061-ceb9ae271dd5 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:08:16Z |
| publishDate | 2021 |
| publisher | Cell Press |
| record_format | dspace |
| spelling | oxford-uuid:bda82407-db76-4c15-b061-ceb9ae271dd52022-05-17T08:04:05ZMammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammalsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:bda82407-db76-4c15-b061-ceb9ae271dd5EnglishSymplectic ElementsCell Press2021Brocklehurst, NPanciroli, EBenevento, GBenson, RBJAdaptive radiations are hypothesised as a generating mechanism for much of the morphological diversity of extant species 1,2,3,4,5,6,7 . The Cenozoic radiation of placental mammals, the foundational example of this concept 8,9 , gave rise to much of the morphological disparity of extant mammals, and is generally attributed to relaxed evolutionary constraints following the extinction of non-avian dinosaurs 10,11,12,13 . However, study of this and other radiations has focussed on variation in evolutionary rates 4,5,7,14 , leaving the extent to which relaxation of constraints enabled the origin of novel phenotypes less well-characterised 15,16,17 . We evaluate constraints on morphological evolution among mammaliaforms (mammals and their closest relatives) using a new method that quantifies the capacity of evolutionary change to generate phenotypic novelty. We find that Mesozoic crown-group therians, which include the ancestors of placental mammals, were significantly more constrained than other mammaliaforms. Relaxation of these constraints occurred in the mid-Paleocene, postdating the extinction of non-avian dinosaurs at the K/Pg boundary, instead coinciding with important environmental shifts and with declining ecomorphological diversity in non-theriimorph mammaliaforms. This relaxation occurred even in small-bodied Cenozoic mammals weighing <100g, which are unlikely to have competed with dinosaurs. Instead, our findings support a more complex model whereby Mesozoic crown therian evolution was in-part constrained by co-occurrence with disparate mammaliaforms, as well as by presence of dinosaurs, within-lineage incumbency effects and environmental factors. Our results demonstrate that variation in evolutionary constraints can occur independently of variation in evolutionary rate; and that both make important contributions to the understanding of adaptive radiations. |
| spellingShingle | Brocklehurst, N Panciroli, E Benevento, G Benson, RBJ Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals |
| title | Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals |
| title_full | Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals |
| title_fullStr | Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals |
| title_full_unstemmed | Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals |
| title_short | Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals |
| title_sort | mammaliaform extinctions as a driver of the morphological radiation of cenozoic mammals |
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