Nasal Morphometry in Marmosets: Loss and Redistribution of Olfactory Surface Area

Abstract

The two major groups of primates differ in internal nasal anatomy. Strepsirrhines (e.g., lemurs) have more numerous turbinals and recesses compared with haplorhines (e.g., monkeys). Since detailed quantitative comparisons of nasal surface area (SA) have not been made, we measured mucosa in serially sectioned monkeys (Callithrix jacchus, Cebuella pygmaea). Data were compared with previously published findings on the mouse lemur, Microcebus murinus. The nasal airways were digitally reconstructed using computed tomography scanned heads of Cebuella and Microcebus. In addition, morphometric and functional analyses were carried out using segmented photographs of the histological sections of Cebuella and Microcebus. The SA of the ethmoturbinal complex is about half as large in marmosets compared with Microcebus, and is covered with less olfactory mucosa (18%-24% in marmosets, compared with 50% in Microcebus). Whereas the ethmoturbinal complex of Microcebus bears half of the total olfactory mucosa in the nasal airway, most (80%) olfactory mucosa is distributed on other surfaces in the marmosets (e.g., nasal septum). A comparison to previously published data suggests all primate species have less olfactory surface area (OSA) compared with other similar-sized mammals, but this is especially true of marmosets. Taken together, these findings support the hypothesis that there is a reduced OSA in at least some haplorhines, and this can be linked to diminished posterosuperior dimensions of the nasal fossae. However, haplorhines may have minimized their olfactory loss by redistributing olfactory mucosa on non-turbinal surfaces. Our findings also imply

Anatomical Details of the Rabbit Nasal Passages and Their Implications in Breathing, Air Conditioning, and Olfaction

“…b. The lateral recess (pink color) is fitted compactly between the MT and ET, in contrast to the outwardly protruding recess in deer (Ranslow et al, ), Marmosets (Smith et al, ), and humans (Xi et al, c). The nasal septum ends at the NM region and the two nasal passages merge at the anterior point (approximately 43.0 mm from the naris) of the ET region.…”

“…Moreover, MRI performs better than CT in resolving the interface of air and soft‐tissues (De Rycke et al, ). To date, only a few studies reported detailed regional morphometric data for dogs (Craven et al, ), deer (Ranslow et al, ), marmosets (Smith et al, ), and humans (Orhan et al, ; Xi et al, ). Moreover, few studies considered the morphometry of the rabbit nasal airway.…”

Comparative Morphology and Histology of the Nasal Fossa in Four Mammals: Gray Squirrel, Bobcat, Coyote, and White‐Tailed Deer

“…Smith et al () found an interesting difference in the distribution of OE between two marmoset species ( Callithrix jaachus , Cebuella pygmaea ) and the lesser mouse lemur ( Microcebus murinus ). Both of the marmosets had more than 70% of their OE located on surfaces other than the ethmoturbinals, such as paranasal spaces and the septum.…”

“…Comparison of mean percentage of total nasal fossa area covered by olfactory epithelium in seven mammalian orders. Data are from the four focal species used in this study as well as from Smith et al (2012Smith et al ( , 2014.…”

“…Early studies of the mammalian nasal fossa relied on visualization of coronal sections of various noses (Negus, ) and quantitative measurements taken by covering the surface with paper squares or manual tracings of projected images (Adams, ). Advances in high‐resolution medical imaging, such as computed tomography (CT) and magnetic resonance imaging (MRI), have enabled three‐dimensional reconstruction of the nasal fossa in various mammals (Zhao et al, ; Craven et al, ; Eiting et al, , Smith et al, ). However, detailed histological examinations of the distribution of OE versus nonsensory epithelium within the nose are lacking for many of these species, and yet such data are essential to understanding the function of the turbinals and the nasal cavity in general.…”