The evolutionary reality of higher taxa in mammals.
Species are generally regarded as a fundamental unit of biodiversity. By contrast, higher taxa such as genera and families, while widely used as biodiversity metrics and for classification and communication, are generally not believed to be shaped by shared evolutionary processes in the same way as species. We use simulations to show that processes which are important for emergence of evolutionarily significant units (ESUs) at the species level, namely geographical isolation and ecological divergence, can generate evolutionary independence above the species level and thereby lead to emergence of discrete phylogenetic clusters (higher ESUs). Extending phylogenetic approaches for delimiting evolutionarily significant species to broader phylogenetic scales, we find evidence for the existence of higher ESUs in mammals. In carnivores, euungulates and lagomorphs the hierarchical level of units detected correspond, on average, to the level of family or genus in traditional taxonomy. The units in euungulates are associated with divergent patterns of body mass, consistent with occupation of distinct ecological zones. Our findings demonstrate a new framework for studying biodiversity that unifies approaches at species and higher levels, thus potentially restoring higher taxa to their historical status as natural entities.
Division of Biology, Imperial College London, , Silwood Park Campus, Berkshire SL5 7PY, UK, Department of Ecology, Environment and Plant Sciences, Stockholm University, , 10691 Stockholm, Sweden.
Aelys M
AM
Humphreys
Timothy G
TG
Barraclough
D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D045303:Cytochromes b / Q000235:genetics; D008322:Mammals / Q000145:classification / Q000235:genetics / Q000502:physiology*; D008962:Models, Theoretical; D010802:Phylogeny; D017422:Sequence Analysis, DNA
D045303:Cytochromes b
Artiodactyla; Carnivora; Lagomorpha; Perissodactyla; adaptive radiation; diversification