Department of Biological Sciences, University of Manitoba, Winnipeg, Canada; Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China; State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China; Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Southern Medical University, Guangzhou, China
Triston G Eastman
Department of Biological Sciences, University of Manitoba, Winnipeg, Canada
Hannah Czolacz
Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, United Kingdom
Shuhao Li
Department of Biological Sciences, University of Manitoba, Winnipeg, Canada
Akio Shinohara
Department of Bio-resources, Division of Biotechnology, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan
Shin-ichiro Kawada
Department of Zoology, Division of Vertebrates, National Museum of Nature and Science, Tokyo, Japan
Mark S Springer
Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, Riverside, United States
Michael Berenbrink
Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, United Kingdom
The speciose mammalian order Eulipotyphla (moles, shrews, hedgehogs, solenodons) combines an unusual diversity of semi-aquatic, semi-fossorial, and fossorial forms that arose from terrestrial forbearers. However, our understanding of the ecomorphological pathways leading to these lifestyles has been confounded by a fragmentary fossil record, unresolved phylogenetic relationships, and potential morphological convergence, calling for novel approaches. The net surface charge of the oxygen-storing muscle protein myoglobin (ZMb), which can be readily determined from its primary structure, provides an objective target to address this question due to mechanistic linkages with myoglobin concentration. Here, we generate a comprehensive 71 species molecular phylogeny that resolves previously intractable intra-family relationships and then ancestrally reconstruct ZMb evolution to identify ancient lifestyle transitions based on protein sequence alone. Our phylogenetically informed analyses confidently resolve fossorial habits having evolved twice in talpid moles and reveal five independent secondary aquatic transitions in the order housing the world’s smallest endothermic divers.
