Meeting Abstract
Tetraodontid pufferfishes, with 187 species comprising 28 genera, have the smallest genomes of any vertebrate, can inflate themselves as defense against predators, have a bifurcated oral beak, and jaw closing muscles divided into as many 8 segments. They have also invaded freshwater on at least eight occasions across four continents. However, unlike other tropical marine-derived lineages (MDLs), pufferfishes have only invaded freshwater rather recently, relative to other marine invaders like stingrays, anchovies, and needlefishes. This study used micro-computed tomography to quantify feeding morphology traits in marine and freshwater tetraodontids and phylogenetic comparative methods to examine how morphological diversification in puffers has proceeded across the marine to freshwater transition. Freshwater pufferfishes do not have greater functional diversity in jaw morphology than saltwater pufferfishes. These methods also recovered widespread convergence in jaw function among many pufferfish dietary guilds. Omnivores, encrusted-prey specialists, and molluscivores exhibited the greatest convergence, while corallivores and crustacivores showed little to no convergence with other guilds across the first three PC axes. However, in at least one radiation of freshwater pufferfishes in Africa (Chelodontops spp.), we find evidence of novel selective regime acting on the feeding mechanics of these particular freshwater puffers. One of these Chelodontops species has actually re-invaded marine habitats, suggesting for these taxa, freshwater habitats have been catalysts for ecomorphological novelty. Tetraodontid feeding systems reveal themselves to be highly adaptable to myriad ecological niches and prey materials, whether in freshwater or marine habitats.
