Morphology of laryngeal cartilage of the nine‐banded armadillo (Dasypus novemcinctus) Linnaeus, 1758

Abstract

Armadillos, Xenarthras representatives, known for adaptability to different ecosystems, own specific morphophysiological characteristics that are not known and deserve to be studied. The aim of this study was to describe the morphology of cartilage of the larynx of the nine-banded armadillo (Dasypus novemcinctus). Five dead armadillos were donated by the Chico Mendes Institute of Biodiversity (ICMBio-PI) to the Federal University of Piauí. The animals were fixed and dissected for removal of the larynx. The cartilages were identified and described, photodocumented, and schematized. Fragments with about 0.5 cm of each cartilage were collected and submitted to classical histology for Hematoxylin-Eosin coloring. The slides were assembled in enterlan and analyzed under a light microscope. The larynx of the armadillo (D. novemcinctus) is located in the mentonian region, ventral to the esophagus, and due to the total positioning of the tongue in the oral cavity, there is also a cranial cervical position in this species. The larynx has five cartilages, they are: a cricoid, a thyroid, an epiglottis, and two arytenoids. The corniculate process is present; however, the cuneiform process is absent. The epiglottis has a discrete bifurcation at its apex. In all cartilages epithelial variations are observed. The tissues are varied from squamoso stratified to cylindrical pseudostratified, with propria lamina rich in mucoserosas glands. With the exception of epiglottic cartilage, predominantly elastic, the rest are hyaline. The larynx of D. novemcinctus, although the same number of cartilages, differs morphologically and microscopically from the larynx of other species.

Histomorphology of the lower respiratory tract in the Indian crested porcupine (Hystrix indica)

“…We detected seromucinous glands in the lamina propria (subepithelial glands) throughout the larynx, as observed in rats (Treuting et al., 2018), coatis (Oliveira et al., 2012) and agoutis (Silva et al., 2014), different from the nine‐banded armadillo, which lacks glands (Fonseca et al., 2017). Furthermore, subepithelial mucous or seromucinous glands are distributed only within portions of the larynx in mice (Treuting et al., 2018).…”

“…The arytenoid epithelia in coatis (Oliveira et al, 2012) and the ICP are covered with a squamous stratified epithelium, compared with a pseudostratified columnar epithelium in the nine-banded armadillo (Fonseca et al, 2017). In the mouse and rat, an intermediate epithelium (composed of non-ciliated, cuboidal-to-flattened cells) is present on the surface of the arytenoid cartilage (Treuting et al, 2018).…”

“…We did not detect taste buds on the laryngeal surface of the epiglottis epithelium in the ICP. Furthermore, taste buds are not present on the surface of the epiglottis in the nine‐banded armadillo (Fonseca et al., 2017). These studies suggested obvious species differences, probably linked to feeding habits.…”

“…Morphological studies of the structure of the respiratory system are essential to understand vertebrate behaviour and physiology. Accordingly, characterisation of the morphological and histological features of the respiratory system is a major research goal (Fonseca et al, 2017; Mario et al., 2018; Oliveira et al., 2012). Since rodents have the potential to spread zoonotic respiratory diseases, studies of the respiratory system have focused on rats, guinea pigs, mice and others (Enria & Pinheiro, 2000; Calisher et al., 2003; Hill & Brown, 2011; Blagojevic et al, 2018; Ilgun et al., 2014; Treuting & Dintzis, 2012; Yarto‐Jaramillo, 2011).…”

Morphological features of lower respiratory tract of nine‐banded armadillo (Dasypus novemcinctus, Linnaeus, 1758)

“…The morphological peculiarities in the cartilages that make up the larynx (Fonseca et al., 2017), nasal cavity (Silva, Cavalcante, Araújo, et al, 2015) and central nervous system (Araújo et al, 2015) were previously described by our research group, emphasizing the importance of continuing research with this animal, for its use in clinical investigations, besides to critical implications for biodiversity conservation policies for this species (Silva, Cavalcante, Araújo, et al, 2015). In this scenario, the purpose of this proposal was to perform a morphological analysis of the lower respiratory tract of the nine‐banded armadillo.…”