Descriptive studies on the tongue of two micro‐mammals inhabiting the Egyptian fauna; the Nile grass rat (Arvicanthis niloticus) and the Egyptian long‐eared hedgehog (Hemiechinus auritus)

Abstract

The current study aimed to describe the anatomical features of the tongues of two micro‐mammals common in the Egyptian fauna; the Nile grass rat (Arvicathis niloticus), and the Egyptian long‐eared hedgehog (Hemiechinus auritus). The tongues of five adult individuals of each species were excised and processed histologically, histochemically, and morphometrically. Statistical analysis comparing the relative tongue length in both species showed that there was a significant difference, which may correlate with the difference in feeding preferences. Grossly, the Nile grass rat has a dorsal lingual prominence with bifurcated apex while, the long‐eared hedgehog has a median slight elevation with rounded apex. Numerous forms of mechanical and gustatory papillae are scattered along the lingual dorsal epithelium. The histochemical detection of keratin by Holland's trichrome stain showed an intense expression in the case of A. niloticus and mild expression in H. auritus. The framework of the tongue (entoglossum) is supported by either a core of cartilage in H. auritus or bone in A. niloticus which incorporated in the lingual root. The lingual glands also showed marked variation, the Nile grass rat exhibit dense populations of mucous‐secreting glands and lesser populations of serous‐secreting glands, the contrary is true in H. auritus. In conclusion, the micro and macro‐anatomical features of the tongues of both species showed adaptive changes to accommodate the feeding lifestyle. Such type of studies using mammals from different phylogenetic traits and almost have different feeding preferences provide answers to many research questions related to tongue evolution among mammalian vertebrates.

Morphogenesis of the New Zealand white rabbit tongue (Oryctolagus cuniculus)

“…Consequently, our findings can be illustrated that there were four types of the lingual papilla; one mechanical as (filiform) and three gustatory as (fungiform, foliate and circumvallate) observed in the tongue of rabbits. These results agreed to Abumandour and El‐Bakary (2013a), Al‐Mahmodi (2016b), Iwasaki et al (2001), Massoud and Abumandour (2019), and Nabil and Tawfiek (2020). The precursor of the fungiform papillae of the rat tongue was two rows along the median line of rat tongue (Iwasaki et al, 2001).…”

“…Previously, the most of articles concerned on the description of the lingual appearance with its papillae and its adaptation with the available food particles and the surrounded environmental conditions (Abumandour & El‐Bakary, 2013a, 2013b; Iwasaki, Miyata, & Kobayashi, 1987; Iwasaki, Okumura, & Kumakura, 1999; Kobayashi, Miyata, Takahashi, & Iwasaki, 1989; Kulawik & Godynicki, 2007; Massoud & Abumandour, 2019). The development of the tongue with its papillae on the dorsal surface were examined in different mammalian species as reported in: rabbit (Elnasharty et al, 2013), rat (Iwasaki et al, 1999; Iwasaki, Asami, & Kageyama, 2001), mouse (Iwasaki et al, 1996; Iwasaki et al, 1999), goats (Kim, Cho, Kim, Kim, & Won, 2013), camel, and sheep (Hejazi & Baroughi, 2013).…”

“…Several articles have been published regarding the morphogenesis and the angio‐architecture of the lingual papillae in various animal species including the rabbit (Abumandour, 2014; Abumandour & El‐Bakary, 2013a; Elnasharty, El Sharaby, & Noreldin, 2013; Fujimoto, Yamamoto, Yoshizuka, & Yokoyama, 1993; Kulawik & Godynicki, 2007; Kulawik & Godynicki, 2009; Kulawik & Godynicki, 2013; Nonaka, Zheng, & Kobayashi, 2008), rat (Massoud & Abumandour, 2019), and (Iwasaki, Yoshizawa, & Kawahara, 1996) in the mouse. While the general structure of the tongue in rabbit was published (Barone et al, 1973).…”

“…While the general structure of the tongue in rabbit was published (Barone et al, 1973). The mammalian tongue has a characteristic structure of lingual papillae (Abumandour, 2014; El‐Mansi, Al‐Kahtani, & Abumandour, 2019; Iwasaki, 2002; Kobayashi, Jackowiak, Frackowiak, Yoshimura, & Kumakura, 2005; Massoud & Abumandour, 2019, 2020). (Abumandour, 2014; Abumandour & El‐Bakary, 2013b; Haddad et al, 2019) in rabbit, bat, and cats added that, there are strong adaptation between the lingual papillae development and feeding and mastication behaviour in suckling and adult feral cats.…”

Ultrastructural features on the oral cavity floor (tongue, sublingual caruncle) of the Egyptian water buffalo (Bubalus bubalis): gross, histology and scanning electron microscope

“…The ruminant's species similar to the herbivorous mammals characterized by the presence of the large, rounded prominence named the torus linguae that bordered rostrally by the deep fossa named the fossa linguae on the dorsal lingual surface of the body as described in the published textbooks about the ruminant's species (27), in addition to the some published articles about the ruminant's species as in; Egyptian water buffalo (12,13), cattle-yak Bos taurus (6), reeves' muntjac deer Muntiacus reevesi (28), Alpaca Vicugna pacos (29). Also, the characteristic lingual prominence was described in other herbivorous mammalian species as in; New Zealand white rabbits (26), Nile grass rat Arvicanthis niloticus (30). Meanwhile, this lingual prominence was absent in the tongue of the carnivorous, omnivorous monkeys and pigs (24,31).…”