title: Evidence for determinism in species diversification and contingency in phenotypic evolution during adaptive radiation.
abstract: Adaptive radiation (AR) theory predicts that groups sharing the same source of ecological opportunity (EO) will experience deterministic species diversification and morphological evolution. Thus, deterministic ecological and morphological evolution should be correlated with deterministic patterns in the tempo and mode of speciation for groups in similar habitats and time periods. We test this hypothesis using well-sampled phylogenies of four squamate groups that colonized the New World (NW) in the Late Oligocene. We use both standard and coalescent models to assess species diversification, as well as likelihood models to examine morphological evolution. All squamate groups show similar early pulses of speciation, as well as diversity-dependent ecological limits on clade size at a continental scale. In contrast, processes of morphological evolution are not easily predictable and do not show similar pulses of early and rapid change. Patterns of morphological and species diversification thus appear uncoupled across these groups. This indicates that the processes that drive diversification and disparification are not mechanistically linked, even among similar groups of taxa experiencing the same sources of EO. It also suggests that processes of phenotypic diversification cannot be predicted solely from the existence of an AR or knowledge of the process of diversification.
authors.affiliation: Department of Biology, The College of Staten Island, The City University of New York, 2800 Victory Boulevard, Staten Island, NY 10314, USA. frank.burbrink@csi.cuny.edu
authors.forename: Frank T
authors.initials: FT
authors.lastname: Burbrink
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Edward A
authors.initials: EA
authors.lastname: Myers
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Brandley
authors.forename: R Alexander
authors.initials: RA
authors.lastname: Pyron
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D017753:Ecosystem; D016013:Likelihood Functions; D010802:Phylogeny; D012911:Snakes / Q000502:physiology*; D013045:Species Specificity