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Nasal turbinals, scrolled thin bones of the nasal cavity, increase surface area for conditioning inspired air or for olfaction in mammals. To assess function in Eptesicus fuscus (Big Brown Bat), we quantify surface area of respiratory and olfactory turbinals from birth to adult size, using data from microCT scans before and after iodine staining. Surface area of each turbinal is significantly correlated with postnatal age and cranial length. The surface area of the maxilloturbinal and first ethmoturbinal (ET I) grows faster, relative to skull size, than surface area of caudal ethmoturbinals or the frontoturbinal. Histological examination of selected specimens reveals ET I grows disproportionately more presumptive respiratory mucosa than olfactory mucosa, supporting the hypothesis that ET I has a dual function. Lastly, we find that distribution of olfactory mucosa in the caudal nasal cavity diminishes with age. Our findings suggest a reduction in olfactory function in E. fuscus, perhaps due to a diminished role in food acquisition by this aerial insectivore.
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The nasal cavity in agoutis (Dasyprocta spp.): a micro-computed tomographic and histological study
Abstract Nasal anatomy in rodents is well-studied, but most current knowledge is based on small-bodied muroid species. Nasal anatomy and histology of hystricognaths, the largest living rodents, remains poorly understood. Here, we describe the nasal cavity of agoutis ( Dasyprocta spp.), the first large-bodied South American rodents to be studied histologically throughout the nasal cavity. Two adult agoutis were studied using microcomputed tomography, and in one of these, half the snout was serially sectioned and stained for microscopic study. Certain features are notable in Dasyprocta . The frontal recess has five turbinals within it, the most in this space compared to other rodents that have been studied. The nasoturbinal is particularly large in dorsoventral and rostrocaudal dimensions and is entirely non-olfactory in function, in apparent contrast to known muroids. Whether this relates solely to body size scaling or perhaps also relates to directing airflow or conditioning inspired air requires further study. In addition, olfactory epithelium appears more restricted to the olfactory and frontal recesses compared to muroids. At the same time, the rostral tips of the olfactory turbinals bear at least some non-olfactory epithelium. The findings of this study support the hypothesis that turbinals are multifunctional structures, indicating investigators should use caution when categorizing turbinals as specialized for one function (e.g., olfaction or respiratory air-conditioning). Caution may be especially appropriate in the case of large-bodied mammals, in which the different scaling characteristics of respiratory and olfactory mucosa result in relative more of the former type as body size increases.
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- Award ID(s):
- 1830919
- PAR ID:
- 10386944
- Date Published:
- Journal Name:
- Vertebrate Zoology
- Volume:
- 72
- ISSN:
- 1864-5755
- Page Range / eLocation ID:
- 95 to 113
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3897/vz.72.e76047
