title: Tightly congruent bursts of lineage and phenotypic diversification identified in a continental ant radiation.
abstract: Adaptive diversification is thought to be shaped by ecological opportunity. A prediction of this ecological process of diversification is that it should result in congruent bursts of lineage and phenotypic diversification, but few studies have found this expected association. Here, we study the relationship between rates of lineage diversification and body size evolution in the turtle ants, a diverse Neotropical clade. Using a near complete, time-calibrated phylogeny we investigated lineage diversification dynamics and body size disparity through model fitting analyses and estimation of per-lineage rates of cladogenesis and phenotypic evolution. We identify an exceptionally high degree of congruence between the high rates of lineage and body size diversification in a young clade undergoing renewed diversification in the ecologically distinct Chacoan biogeographical region of South America. It is likely that the region presented turtle ants with novel ecological opportunity, which facilitated a nested burst of diversification and phenotypic evolution within the group. Our results provide a compelling quantitative example of tight congruence between rates of lineage and phenotypic diversification, meeting the key predicted pattern of adaptive diversification shaped by ecological opportunity.
authors.affiliation: Department of Biological Sciences, George Washington University, Washington, District of Columbia, 20052. slprice@gmail.com.
authors.forename: Shauna L
authors.initials: SL
authors.lastname: Price
authors.affiliation: Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands.
authors.forename: Rampal S
authors.initials: RS
authors.lastname: Etienne
authors.affiliation: Department of Biological Sciences, George Washington University, Washington, District of Columbia, 20052.
authors.forename: Scott
authors.initials: S
authors.lastname: Powell
mesh_terms: D000818:Animals; D001000:Ants / Q000145:classification*; D005075:Biological Evolution; D049628:Body Size; D017753:Ecosystem; D049810:Genetic Speciation; D008957:Models, Genetic; D010641:Phenotype; D010802:Phylogeny; D013020:South America
keywords: Cephalotes; Chacoan region; ecological opportunity; trait evolution; turtle ants