Surface ultrastructural (SEM) characteristics of oropharyngeal cavity of house sparrow (Passer domesticus)

Abstract

The focus of the present study is to provide a full morphological description of the oropharyngeal cavity of the house sparrow. The head of six birds was prepared for gross examination and by stereo and electron microscopy. The bifid lingual apex has multiple long, rostrally directed needle-like processes. The lateral border of the apex carries rostromedially directed needle-like processes. The dorsal lingual surface of the apex and body carries numerous caudomedially directed filiform papillae and many orifices of lingual salivary glands. The lingual body is divided into two parts: rostral and caudal. The caudal part is divided into two laterally elevated regions by a median groove, while the rostral part is bounded laterally by a rostrodorsally directed papillary row, which on SEM is formed from two rows. On SEM, the lingual root has many orifices of posterior salivary glands. The pharyngeal papillary row is located at the caudal border of the laryngeal mound, but this single papillary row is formed from two rows at SEM magnification. The laryngeal cleft continues caudally as a laryngeal fissure bounded by two longitudinal rows of caudally directed papillae; at high SEM magnification, this fissure is divided into two halves by a median ridge which carries caudally directed papillae on its posterior part. The choanal cleft proceeds rostrally by the median tubercle. There are a small number of orifices of palatine salivary glands. The morphological characters of the oropharyngeal cavity of the sparrow confirm its adaptation to surrounding environmental conditions and available food particles.

Surface ultrastructural descriptions of the oropharyngeal cavity of Anas querquedula

“…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, ).…”

“…The triangular shape is the common form of most avian species as, the galliform, passerine birds, Eurasian hoopoe and house sparrow (Abumandour, ; Abumandour & Gewaily, ; Jackowiak, Skieresz‐Szewczyk, Kwiecinski, Trzcielinska‐Lorych, & Godynicki, ; Parchami et al, ). The other common form of the avian tongue is the elongated tongue as appear in the carnivorous birds (Abumandour & El‐Bakary, ; Emura et al, ), herbivorous birds (Abumandour, ; Abumandour & El‐Bakary, ), and the water birds as in the current study and the Eurasian coot (Abumandour & El‐Bakary, ), the domestic duck (Skieresz‐Szewczyk & Jackowiak, ; Skieresz‐Szewczyk, Jackowiak, & Ratajczak, ), and the domestic goose (Iwasaki et al, ; Jackowiak et al, ). There are other lingual forms such as the tongue‐like a brush as in the nectarivorous birds (Rico‐Guevara & Rubega, ), the mushroom‐like tongue as in the cormorants (Jackowiak et al, ), a toothpick‐like tongue in the Japanese pygmy woodpecker (Emura et al, ) and the needle‐like shape tongue as in the Little Egret, heron (Emura, ).…”

“…The current study observed that the median longitudinal lingual sulcus extended along the dorsal surface of the lingual apex and body, in which it is deep in the rostral ⅔ of the tongue and shallow in the caudal ⅓ of the tongue on the lingual prominence, similar position of the groove reported in Eurasian coot (Abumandour & El‐Bakary, ), and common kestrel (Abumandour & El‐Bakary, ). While, the shallow median lingual sulcus located along the dorsal surface of the lingual body including the lingual prominence observed in the Northern pintail (El Bakary, ) and domestic duck (Skieresz‐Szewczyk & Jackowiak, ), while it is present only on the dorsal surface of the lingual body (Jackowiak et al, ) in the domestic goose, but it is present on the anterior region of the lingual body and absent in the lingual apex and prominence of the Middendorff's bean goose (Iwasaki et al, ), but present in the caudal part of the lingual body as noted in the house sparrow (Abumandour, ).…”

“…The focused point for the most researchers is the studying the morphological appearance of the tongue and their adaptation with the different feeding styles (Abumandour & El‐Bakary, ; Al‐Ahmady Al‐Zahaby, ; Jackowiak, Andrzejewski, & Godynicki, ; Pasand, Tadjalli, & Mansouri, ). Recently, there are some morphological articles designed to study the morphological characterization of the oropharyngeal cavity (tongue, laryngeal mound, and the palate) and its adaptations with the feeding behavior and the available food materials (Abumandour, ; Abumandour & El‐Bakary, ; Abumandour & Gewaily, ; Kobayashi, Kumakura, Yoshimura, Inatomi, & Asami, ; Santos et al, ).…”