1. Olfactory epithelium and ontogeny of the nasal chambers in the bowhead whale ( <scp> Balaena mysticetus </scp> )
- Author
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Daniel J. Hillmann, Ian C. Farnkopf, John Craig George, J. G. M. Thewissen, Robert Suydam, and Takushi Kishida
- Subjects
0301 basic medicine ,Nasal cavity ,Bowhead Whale ,Histology ,Olfactory receptor neuron ,Cribriform plate ,Olfaction ,03 medical and health sciences ,0302 clinical medicine ,Olfactory Mucosa ,otorhinolaryngologic diseases ,medicine ,Animals ,Balaena ,Ecology, Evolution, Behavior and Systematics ,biology ,Skull ,Anatomy ,biology.organism_classification ,Olfactory bulb ,Ethmoid Bone ,030104 developmental biology ,medicine.anatomical_structure ,biology.protein ,Nasal Cavity ,Olfactory epithelium ,Olfactory marker protein ,030217 neurology & neurosurgery ,Biotechnology - Abstract
In a species of baleen whale, we identify olfactory epithelium that suggests a functional sense of smell and document the ontogeny of the surrounding olfactory anatomy. Whales must surface to breathe, thereby providing an opportunity to detect airborne odorants. Although many toothed whales (odontocetes) lack olfactory anatomy, baleen whales (mysticetes) have retained theirs. Here, we investigate fetal and postnatal specimens of bowhead whales (Balaena mysticetus). Computed tomography (CT) reveals the presence of nasal passages and nasal chambers with simple ethmoturbinates through ontogeny. Additionally, we describe the dorsal nasal meatuses and olfactory bulb chambers. The cribriform plate has foramina that communicate with the nasal chambers. We show this anatomy within the context of the whole prenatal and postnatal skull. We document the tunnel for the ethmoidal nerve (ethmoid foramen) and the rostrolateral recess of the nasal chamber, which appears postnatally. Bilateral symmetry was apparent in the postnatal nasal chambers. No such symmetry was found prenatally, possibly due to tissue deformation. No nasal air sacs were found in fetal development. Olfactory epithelium, identified histologically, covers at least part of the ethmoturbinates. We identify olfactory epithelium using six explicit criteria of mammalian olfactory epithelium. Immunohistochemistry revealed the presence of olfactory marker protein (OMP), which is only found in mature olfactory sensory neurons. Although it seems that these neurons are scarce in bowhead whales compared to typical terrestrial mammals, our results suggest that bowhead whales have a functional sense of smell, which they may use to find prey.
- Published
- 2021