Like many other fish, some cichlids capture their prey by creating sub-ambient pressure in their mouths to draw in water. This is done by rapidly expanding the buccal cavity, a movement created by the complex elements and linkages of the craniofacial skeleton. Due to the complexity of the system, the relationship between their morphology and suction feeding performance is convoluted.
Much of this work is focused around the differences between species at opposite ends of a trophic spectrum ranging from algae scrapers to suction feeders. Labeotropheus fuelleborni (LF) is a representative algae scraper and Maylandia zebra (MZ, AKA Metriaclima zebra) is a generalist well adapted to suction feeding.
Feeding strikes are qualitatively different between LF, MZ, and hybrids.
We found that hybrids homozygous for the LF allele of a SNP at sox9b had a much stronger relationship between morphology and performance than did any other grouping of animals. This suggests a novel role that craniofacial genes could play in determining an animals fitness.