Meeting Abstract

P2.65  Wednesday, Jan. 5  Does Cribriform Morphology Predict Olfactory Function? BIRD, DJ; GREEN, P*; VAN VALKENBURGH, B; University of California Los Angeles; University of California Los Angeles; University of California Los Angeles dbirdseed@gmail.com

As yet, we know very little about olfactory function in extinct mammals. One of the only preserved remnants of olfactory anatomy in fossil mammals is the cribriform plate, a perforated bony cup at the anterior base of the brain case. It is through the holes (foramina) of this plate that the axons from olfactory epithelium of extinct mammals once passed and entered the olfactory bulb of the brain. Among living mammals there is marked variation in cribriform morphology across species. Both the surface area of the plate and the number and size of its foramina vary among species and likely reflect aspects of olfactory ability. This suggests that the cribriform plate may be established as a metric for olfactory function. Toward this end we have compared cribriform morphology among living species of arctoid Carnivora, (e.g. mustelids, pinnipeds, ursids), a group that includes closely related species with distinct ecologies (terrestrial vs. aquatic), offering a clear comparison along a spectrum of olfactory demands. Preliminary measurements using 3-D imaging software and computer tomography (CT) scans reveal that aquatic species have fewer cribriform foramina, as well as a reduced plate surface area, as compared with their terrestrial relatives. This is consistent with studies suggesting a reduced role of olfaction in some aquatic mammals. By using a fully digital approach we take all measurements from virtual skulls, avoiding any destruction of specimens. Using this method to fully measure variation in cribriform morphology holds promise for new insights into the olfactory ecology of living as well as extinct species.