Anatomical investigations of the tongue and laryngeal entrance of the Egyptian laughing dove Spilopelia senegalensis aegyptiaca in Egypt

Abstract

In the present work, the first full anatomical description of the tongue and laryngeal entrance of the Egyptian laughing dove Spilopelia senegalensis aegyptiaca, which was obtained with the aid of scanning electron microscopy (SEM) and histological techniques, is provided. The lingual apex was rounded and the cranially convex papillary crest exhibited a transverse papillary row, in addition to another row consisting of two giant papillae. Papillae were not observed on the elevated, triangular laryngeal mound except for the glottic opening, which was bounded by two lateral elevated borders that presented a row of small papillae. Two fissures occurred on the laryngeal mound: a rostral fissure at the rostral border of the laryngeal mound, and a caudal fissure that occurred caudally to the glottic opening and continued caudally as the laryngeal fissure. SEM analysis showed filiform papillae on the dorsal surface of the apex and body, and indicated that each giant papilla was long with a pointed apex and exhibited one or two secondary papillae on its surface. The dorsal surface of the lingual root exhibited numerous openings of the lingual salivary glands. The caudal part of the laryngeal mound presented numerous openings of the laryngeal salivary glands. Histologically, the dorsal surface of the anterior and middle lingual part was covered with a thick and stratified squamous epithelium. The anterior and middle lingual part presented entoglossum cartilaginous ossification of the entoglossal bone, which had numerous chondrocytes lodged within the lacunae of the entoglossum. The lingual glands appeared in the middle and caudal lingual part.

Surface ultrastructural descriptions of the oropharyngeal cavity of Anas querquedula

“…Although, the lingual papillary crest absent in the penguin (Kobayashi et al, ), woodpecker (Emura et al, ), and ratite birds (Santos et al, ). The current investigation confirmed that reported in other avian species that the presence of transverse lingual papillary crest with its mechanical caudally directed conical papillae helping to prevent regurgitation and to direct food to esophagus (Abumandour, ; Abumandour & El‐Bakary, , ; Jackowiak et al, ).…”

“…There are minor anatomical variations in the number of the transverse papillary row of the lingual crest among the different bird species. The current work noted the presence of only one transverse papillary row, similar observation observed by Abumandour and El‐Bakary (, , )), but the two transverse papillary row noted by Abumandour (), Abumandour and El‐Bakary (), Parchami et al (), Skieresz‐Szewczyk and Jackowiak (). Also, there are some variations in the appearance of the lingual papillary crest as in the present study, the papillary crest take the transverse appearance, similar to that reported in goose (Iwasaki et al, ) and coot (Abumandour & El‐Bakary, ), while the famous appearance of the papillary crest in the most avian species is the V‐shape as reported by Abumandour (, ), El Bakary (), and Parchami et al () while, it take the W‐shaped in the hoopoe (El‐Bakary, ), but it take a U‐shaped appearance in the cattle egret (Al‐Ahmady Al‐Zahaby, ).…”

“…The lingual shape is species‐specific among avian species and related to the shape of the lower jaw, feeding styles, types of available food particles (Abumandour & El‐Bakary, , ; Jackowiak, Skieresz‐Szewczyk, Godynicki, Iwasaki, & Meyer, ). The shape of the bird's tongue contains two possibilities for adaptation to a lower beak; the first possibility, include that it is closely correlated with the lower beak as observed in the current work and by Abumandour (), Abumandour and El‐Bakary (, ), Emura, Okumura, and Chen (), and Parchami, Dehkordi, and Bahadoran (), but the second possibility, include that there is no relationship between the shape of the tongue and the size of the lower beak in which there is two conditions of the tongue, may be short tongue such as the hoopoe (Abumandour & Gewaily, ), the ratite birds (Jackowiak et al, ; Santos et al, ), and the white stork (Jackowiak et al, ) or may be the tongue longer than the lower jaw such as in the wood‐peckers bird (Emura, Okumura, & Chen, ). The current investigation observed the presence of the elongated flat non‐protrusible tongue of the Garganey ( A. querquedula ) extended to fill the full limit of the lower beak, except the tip of the lower beak, similar to that reported in other water bird duck and goose (Jackowiak et al, ;Marzban Abbasabadi & Sayrafi, ; Skieresz‐Szewczyk & Jackowiak, ).…”

“…According to the previously published data, the presence of the papillary crest not correlated with the feeding behavior or types of available food particles (Abumandour & El‐Bakary, , ). The evidence of this, it is found in the carnivorous, omnivorous, and herbivorous birds as noted in the Eurasian coot (Abumandour & El‐Bakary, ), domestic duck (Marzban Abbasabadi & Sayrafi, ; Skieresz‐Szewczyk et al, ; Skieresz‐Szewczyk & Jackowiak, ), goose (Iwasaki et al, ; Jackowiak et al, ), house sparrow (Abumandour, ), quail (Parchami et al, ), Egyptian laughing dove (Abumandour & El‐Bakary, ), cormorant (Jackowiak et al, ), Eurasian Hobby (Abumandour, ), and common kestrel and Hume's tawny owl (Abumandour & El‐Bakary, ). Although, the lingual papillary crest absent in the penguin (Kobayashi et al, ), woodpecker (Emura et al, ), and ratite birds (Santos et al, ).…”

“…This is clear in the current study on the migratory omnivorous Garganey ( A. querquedula ), as the most water birds has the round‐shaped lingual apex with an anterior spatula‐like structure (Jackowiak et al, ; Marzban Abbasabadi & Sayrafi, ; Skieresz‐Szewczyk & Jackowiak, ), but there is another water birds not contain the lingual nail as the Eurasian coot (Abumandour & El‐Bakary, ), however, the tongue of the nutcracker (one of the passerine birds) has a pair of dagger‐like processes that play an important role in the raising and ejection the seeds toward the median longitudinal lingual sulcus (Jackowiak et al, ). Anatomically, there are numerous shape of the lingual apex among different avian species such as the round lingual apex appeared in the, quail, Egyptian laughing dove and ostrich (Abumandour & El‐Bakary, ; Parchami et al, ; Pasand et al, ), while a pointed apex appeared in the chicken and hoopoe (Iwasaki & Kobayashi, ), but a blunt round apex in ostrich (Pasand et al, ). The current work confirmed that reported by Skieresz‐Szewczyk and Jackowiak ()) that the Anatidae family use the round‐shaped lingual apex with the lingual nail in the pecking process to grabbing the grains with the beak, in which the lingual nail act as a spoon for raise the food particles.…”