Biological Aspects of the Tongue and Oropharyngeal Cavity of the Eurasian Collared Dove (Streptopelia decaocto, Columbiformes, Columbidae): Anatomical, Histochemical, and Ultrastructure Study

Abstract

We characterized the morphological and anatomical adaptations of the lingual microstructures of the Eurasian collared dove and discussed their implications for its dietary niche. We analyzed tongues of nine S. decaocto using histological, histochemical, stereomicroscopic, and scanning electron microscopic techniques. Our findings showed that the tongue is relatively short with a tapered apex that carries a terminal lingual nail. However, the lingual body has median scales and is bordered laterally by filiform papillae. Further, the tongue body bears a distinctive papillary crest. The tongue root is nonpapillate and infiltered with orifices of the posterior salivary glands. The bulky laryngeal mound has a circular glottic fissure, carrying a single row of papillae at the rear edge. Concurrently, our histological and histochemical findings demonstrate that the tongue has taste buds, anterior and posterior salivary glands, along with an elongated entoglossum that extends from lingual apex to root. Besides, ovoid and globular mucous glands displayed intense alcianophilic reactions. More substantially, the palate is made up of three palatine ridges with a caudal choanal cleft that was bounded by two rows of palatine papillae. Our data indicate multiple and novel structural variations for the lingual and palatal sculptures coopted for their feeding style.

Ultrastructural adaptation of the oropharyngeal cavity of the Eurasian common moorhen (Gallinula chloropus chloropus): Specific adaptive dietary implications

“…Functionally, these caudal-oriented pharyngeal papillae are likely to be involved in directing food particles towards the esophagus (El-Mansi et al, 2021;Jackowiak & Godynicki, 2005).…”

“…Avian tongue shape had a species‐specific feature closely related to the lower beak shape, different feeding habits, and environmental adaptation (Abumandour, El‐Bakary, et al, 2021; El‐Mansi et al, 2021; Parchami et al, 2010; Parchami et al, 2010b). The avian species‐differences adaptation of the tongue with the size and shape of the lower beak was clear in the current examined tongue of the Eurasian common moorhen that fitted to the size of the lower beak, the same data shared in some avian species as; quail (Parchami et al, 2010), magpie and raven (Erdogan & Alan, 2012), and buzzard (Erdogan, & Alan AJMr, technique., 2012).…”

“…However, the gustatory papillae were absent in most avian species (Gewaily & Abumandour, 2020; Santos et al, 2011) but well‐developed in mammals (Massoud & Abumandour, 2020). Meanwhile, the gustatory papillae were observed on the tongue of the golden eagle and Eurasian collared dove (El‐Mansi et al, 2021; Parchami et al, 2010). Moreover, instead of gustatory papillae, some avian species possess taste buds at the root (Abumandour & Kandyel, 2020; Jackowiak and Godynicki, 2005).…”

“…The collected samples were fixed at 4°C in 2% formaldehyde, 1.25% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2. Then, the samples were washed in 0.1 M sodium cacodylate containing 5% sucrose, processed through tannic acid, and finally dehydrated in increasing concentrations of ethanol (15 min each in 50%, 70%, 80%, 90%, 95%, and 100% ethanol) (El‐Mansi et al, 2021). The samples were then critical point dried in carbon dioxide, attached to stubs with colloidal carbon, and coated with gold–palladium in a sputtering device.…”

“…Some time ago, the avian tongue had more considerations from all scientists by various anatomical methods to its adaptation with the different feeding habits (Abumandour, Shukry, et al, 2021; Abumandour, Farrag, et al, 2021; Al‐Ahmady, 2016; Crole and Soley, 2010b; Jackowiak & Ludwig, 2008b; Kobayashi et al, 1998; Skieresz‐Szewczyk & Jackowiak, 2016). Over time, the anatomical researchers have resorted to investigating the oropharyngeal cavity and its adaptability with the obtainable food particles in different environmental conditions (Abumandour, El‐Bakary, et al, 2021; Abumandour, Farrag, et al, 2021; El‐Mansi et al, 2020; El‐Mansi et al, 2021; Gewaily & Abumandour, 2020; Mahdy, 2020).…”