The Affect of Ontogeny on Structure and Function of Preopercular Spines in Myoxocephalus polyacanthocephalus

Abstract

I investigated the affect of ontogeny on the structure and function of pre-°©‐opercular spines. By measuring how these spines matched up against the standard length of the animal. Spines were surgically removed from Myoxocephalus polyacanthocephalus and put through puncture tests to measure the required force to puncture a ratio of the spine length. We found that spine length grows isometrically to standard length and force to puncture showed a negative allometry. Meaning that larger individuals had the same size spine to body length ratio but the larger spines is more efficient at puncturing. To assess the structure Finite Elemental Analysis techniques were applied to three different size classes of spines. This analysis showed that smaller spines concentrate the Von Mises stress at the tip while the largest sine dissipates this stress down the dorsal medial ridge. The smallest class of spine also showed a much higher Von Mises stress than the larger spine.