What’s that smell? A Whiff of Gunnel Olfactory Morphology

Abstract

Chemoreception is used to track predators, prey, or find conspecifics. Across the Zoarcoidei suborder, diet varies from herbivory to carnivory. Members of the Pholidae family are found along intertidal shorelines of the east Pacific ocean, and are able to breathe air during low tide. Because of these characteristics -and a knowledge gap of intertidal fish olfactory systemswe examined three species: Apodichthys flavidus, Pholis laeta, and Pholis ornata, all of which are carnivores. In our study we used contrast-enhanced microCT scans and dissections to: 1) characterize the morphology of olfactory systems; and 2) compare the olfactory morphology of two Pholis species to a member of the Apodichthys genus. We found that the two Pholis species have two lamellae per rosette and the average Lamellae Area scales with body length, while Apodichthys flavidus has up to four lamellae per rosette which do not scale with body length. Additionally, the Rosette Area of Apodichtys flavidus is significantly larger than both Pholis species. This study is the first to characterize the olfactory system of Pholids through use of microCT scanning. Further research on members of the Zoarcoidei subfamily would improve understanding on how diet may inform the level of reliance upon the olfactory system; improve our knowledge of how intertidal fishes interact with their extreme environments; and provide new information to sensory biology as a field of study.