Meeting Abstract

64.4  Tuesday, Jan. 6  Did the Fish-Specific Genome Duplication (FSGD) event spawn the teleost radiation? Evidence from the analysis of actinopterygian diversification rates. ALFARO, ME*; HARMON, LJ; CARNEVALE, G; SANTINI, F; Univ. of California, Los Angeles; Univ. of Idaho; Univ. of Pisa; Univ. of California, Los Angeles michaelalfaro@ucla.edu

The genome duplication hypothesis posits that the duplication of the genome in ancestral teleosts is responsible for the startling disparity in species richness between extant teleosts and nonteleosts (~29000 species vs ~50 ). Although several studies have corroborated the genome duplication event, there have been no quantitative tests of whether and how diversification rates differ within and among major fish lineages. Here we use a novel stepwise AIC approach in conjunction with a time-calibrated diversity tree of actinopterygians to test whether birth and death rates have shifted in crown teleosts. We find that the teleosts experienced a significant shift in diversification rates that might coincide with the FSGD. In addition, we find evidence for rate increases in the ancestors of the two largest teleost clades: ostariophysans, and percomorphs. We explore the implications of this model for understanding species richness patterns in fishes.