Meeting Abstract
Elasmobranchs (sharks, skates, and rays) are known for their highly acute olfactory sense. They exhibit wide interspecific variation in their olfactory organ morphology, which has largely been quantified by the number of lamellae the organ houses. Attempts to correlate olfactory organ morphology with ecology and phylogeny have not been explanatory. Recent studies have suggested that the vast variation in olfactory organ morphology may facilitate the flow of water through the nose to deliver odorants to the olfactory epithelia. In this study, we quantify morphological variation in the elasmobranch olfactory organ in multiple species, create physical models inspired by organ morphology, and test the effects of morphology on water flow through the model. We examine organ shape (Fineness ratio), lamellar number, and the spacing between lamellae. Organ fineness ratio (L:W) of hammerhead shark species, which have large laterally expanded cephalofoils, is much greater than other elasmobranch species. The number of lamellae varies by species where some species have more than double, which may impact the surface area available for odor detection. Interlamellar spacing also varied by species, and spacing in some species was 50% larger than others. In general, species with a smaller interlamellar spacing have more lamellae than species with larger interlameller spacing. We expect that fluid dynamics in the model will vary with model morphology. We will build models inspired by organ fineness ratio, number of lamellae, and interlamellar spacing. This data will provide insight on how morphological variation inside elasmobranch noses affects detection of and binding to odorants.
