New paper: Rapid parallel morphological and mechanical diversification of pike cichlids
Check out our most recent paper in Systematic Biology "Rapid Parallel Morphological and Mechanical Diversification of South American Pike Cichlids (Crenicichla)"
Reference: Burress, E.D., L. Pialek, J. Casciotta, A. Almiron, and O. Rican. Rapid Parallel Morphological and Mechanical Diversification of South American Pike Cichlids (Crenicichla). In Press, Systematic Biology, syac018.
In a huge collaborative effort, we assessed the evolutionary history of pike cichlids in the La Plata River Basin (the major drainage in sub-tropical South America). The genetic sampling itself was a huge effort, spanning over 140 samples and more than 40 species. We then inferred the phylogenetic history of the group using ddRAD, including estimating the phylogeny and divergence times as well as gene flow. We also assessed the evolutionary history of feeding ecology, functional morphology, and mechanical properties (i.e., motion) of the jaws, particularly how they relate to functional demands imposed by prey evasiveness.
TLDR: Pike cichlids exhibited a decoupled macroevolutionary response in form and function to prey evasiveness and many-to-one mapping is a mechanism by which pike cichlids have diversified their feeding ecologies without engaging in (further) mechanical trade-offs. There is no history of gene flow between major drainages that may explain their conspicuous adaptive radiation in the Uruguay and Iguazu Rivers, although there is frequent gene flow between some closely-related species.