Pivots and power amplification evolution and functional morphology of feeding in seahorses and their relatives

Meeting Abstract

S3-11  Friday, Jan. 4 15:00 – 15:30  Pivots and power amplification: evolution and functional morphology of feeding in seahorses and their relatives LONGO, SJ; Duke University sjl53@duke.edu https://sarahjlongo.wordpress.com

Power-amplified mechanisms (PAMs) have evolved multiple times independently across the tree of life and allow organisms to increase performance during a diverse array of fitness-related behaviors. PAMs are examples of complex morphological innovations, involving a number of structural components that must act together in harmony, often resulting in extreme performance that would be impossible with muscles alone. PAMs can therefore serve as case studies for the evolution of complex functional morphologies. For example, a power-amplified feeding mechanism has evolved at least once in Syngnathiformes, a group of fishes that includes seahorses, pipefishes, snipefish, and their relatives. Most syngnathiforms possess an elongated snout that they use in an unusual form of prey capture called pivot feeding, whereby dorsal head rotation brings the mouth close to prey. Some lineages have been shown to amplify power during head rotation, resulting in the fastest feeding strikes known in fishes (2ms). Pivot feeding and power amplification involve an array of changes to the feeding morphology compared to other fishes. For instance, modifications to the hyoid apparatus and suspensorium are important for latching during energy storage. A better understanding of the phylogenetic distribution of snout elongation, pivot feeding, power amplification, and hyoid-latching in syngnathiforms and outgroups is necessary to tease apart the morphological adaptations for each function (i.e., pivot feeding versus power amplification). Did the all these traits originate in concert, or was there a sequence of modifications? I will bring together information from the literature, micro-CT, phylogenomics, and biomechanics to describe the evolutionary history of one of the only known power-amplified systems in ray-finned fishes.

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