Meeting Abstract

44.3  Saturday, Jan. 5  Repeated Convergent Evolution of Parental Care Strategies within Xenotilapia, a Genus of Cichlid Fishes from Lake Tanganyika KIDD, M.R.*; HOFMANN, H.A.; The University of Texas at Austin; The University of Texas at Austin mckidd@earthlink.net

The factors promoting the evolution of parental care strategies have been extensively studied in experiment and theory. However, most attempts to examine parental care in an evolutionary context have evaluated broad taxonomic categories. The explosive and recent diversification of East African cichlid fishes offers a unique opportunity to study the evolution of parental care within a species-level phylogeny. We used the monophyletic Ectodini cichlid lineage, which is endemic to Lake Tanganyika. Species of this group display either biparental or maternal only care. In order to reconstruct the evolutionary relationships among 16 species of this lineage we scored 2,500 Amplified Fragment Length Polymorphisms (AFLPs) across the genome. Both parsimony- and distance-based methods of inference produced robust phylogenetic hypotheses with very similar topologies. We find that (i) the Ectodini genera Asprotilapia, Enantiopus and Microdontochromis are all embedded within the genus Xenotilapia; (ii) an early split occurred within the Ectodini between maternal and biparental mouthbrooding species, giving rise to a biparental Xenotilapia clade ancestor; and (iii) during 1 to 2 million years of evolution within the Xenotilapia clade, 5-6 subsequent transitions occurred to maternal care followed by 2-3 reversals back to biparental care. While most previous models suggest that uniparental care (maternal or paternal) arose from biparental care, we conclude from our species-level analysis that the evolution of parental care strategies is not only remarkably fast, but much more labile than previously expected.