Olfactory Epithelium in the Olfactory Recess: A Case Study in New World Leaf‐Nosed Bats

Abstract

The olfactory recess (OR) is a restricted space at the back of the nasal fossa in many mammals that is thought to improve olfactory function. Mammals that have an olfactory recess are usually described as keen‐scented, while those that do not are typically thought of as less reliant on olfaction. However, the presence of an olfactory recess is not a binary trait. Many mammal families have members that vary substantially in the size and complexity of the olfactory recess. There is also variation in the amount of olfactory epithelium (OE) that is housed in the olfactory recess. Among New World leaf‐nosed bats (family Phyllostomidae), species vary by over an order of magnitude in how much of their total OE lies within the OR. Does this variation relate to previously documented neuroanatomical proxies for olfactory reliance? Using data from 12 species of phyllostomid bats, we addressed the hypothesis that the amount of OE within the OR relates to a species' dependence on olfaction, as measured by two commonly used neuroanatomical metrics, the size of the olfactory bulb, and the number of glomeruli in the olfactory bulb, which are the first processing units within the olfactory signal cascade. We found that the percentage of OE within the OR does not relate to either measure of olfactory “ability.” This suggests that olfactory reliance is not reflected in the size of the olfactory recess. We explore other roles that the olfactory recess may play. Anat Rec, 297:2105–2112, 2014. © 2014 Wiley Periodicals, Inc.

Fissures, folds, and scrolls: The ontogenetic basis for complexity of the nasal cavity in a fruit bat (Rousettus leschenaultii)

“…Pneumatization within the frontal recess is a final mechanism observed in infant Rousettus , which expands this paranasal space. Fluid dynamics airflow modeling (e.g., Eiting et al, 2014; Eiting, Perot, & Dumont, 2015) may provide the optimal means for assessing the importance of pneumatization to adult internal nasal form, as is the case for appositional turbinal growth.…”

“…In the present study, we expand our knowledge of age‐related nasal capsule changes with a focus on Chiroptera (bats), an Order in which diversity of nasal form may be argued to exceed that in other groups of mammals, including primates (e.g., Bhatnagar & Meisami, 1998; Eiting, Smith, & Dumont, 2014; Pedersen, 1995; Santana & Lofgren, 2013). Among chiropterans, the pteropodids (fruit bats) have the least specialized, if at all, facial form compared to laryngeal echolocating bat species (Allen, 1882; Giannini, Macrini, Wible, Rowe, & Simmons, 2012).…”

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

“…Early studies of the mammalian nasal fossa relied on visualization of coronal sections of various noses (Negus, 1958) and quantitative measurements taken by covering the surface with paper squares or manual tracings of projected images (Adams, 1972). Advances in highresolution 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, 2006;Craven et al, 2007;Eiting et al, 2014. 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.…”

The ethmoidal region of the skull of <i>Ptilocercus lowii</i> (Ptilocercidae, Scandentia, Mammalia) – a contribution to the reconstruction of the cranial morphotype of primates

“…The oldest known ossified remnants of turbinals are described in the advanced nonmammaliaform cynodont Brasilitherium riograndensis and can be dated back into the Late Triassic . The anteriormost turbinals (in particular the maxilloturbinal, anterior portion of nasoturbinal) and in many species the anterior process of the first ethmoturbinal are covered by respiratory epithelium for warming and moistening the inspired air whereas the posterior turbinals (frontoturbinals, ethmoturbinals, interturbinals), the semicircular crista or lamina as well as the posterodorsal part of the nasal septum are covered by olfactory epithelium that carries the olfactory receptors of the first cranial nerve; the distribution of the olfactory epithelium differs among species and depends on their macrosmatic level (Le Gros Clark, 1951;Ruf, 2004;Rowe et al, 2005;Smith et al, 2007Smith et al, , 2014aEiting et al, 2014;Van Valkenburgh et al, 2014b).…”