Morphology and Morphometry of Lingual Papillae in Adult and Newborn Egyptian Fruit Bats (Rousettus aegyptiacus)

Abstract

The paper presents a comparison of the microscopic structure and morphometric traits of gustatory and mechanical lingual papillae in newborn and adult frugivorous Egyptian fruit bats (Rousettus aegyptiacus). All of the four types of lingual papillae found in adult animals were observed on the tongue surface in the newborn Egyptian fruit bats. After the birth, the gustatory papillae (fungiform and vallate papillae) were especially well-developed, as their structural characteristics, such as morphology of the epithelium and presence of the taste buds, indicate that they have reached almost complete functional traits. Mechanical papillae, particularly filiform papillae, in newborns are still fetal in character. Keratinization processes in the epithelium of these papillae are not advanced and specific structures, such as elongated processes, are missing. The morphometric analysis of the size of papillae and thickness of the mucosal epithelium showed that a complete development of keratinized structures in Egyptian fruit bats occurs at later stages of postnatal development.

Anatomical and surface ultrastructural investigation of the tongue in the straw‐coloured fruit bat (Eidolon helvum, Kerr 1972)

“…Earlier studies on the tongue of some species of nectarivory, frugivory and insectivory showed remarkable variations in lingual papillae resulting from adaptations to the intake of liquid and semi‐liquid food relative to varying seasonal environmental needs (Abumandour & El‐Bakary, 2013; Abumandour, 2014; Emura et al., 2001; Emura, 2009; Heiss et al., 2017; Kobayashi & Shimamura, 1982; Mqokeli & Downs, 2013; Sharma et al., 1999; Taki‐El‐Deen et al., 2013). The present report showed some structural features similar to those seen in fruit‐eating bats previously studied (Birt et al., 1997; Emura et al., 2001; Gunawan et al., 2019; Jackowiak et al, 2009; Shindo et al., 2009; Trzcielinska‐Lorych et al., 2009). Such remarkable similarities as shape and size, variable forms of mechanical papillae (filiform and conical); location, distribution and number of gustatory fungiform and vallate papillae, and with their taste buds (and taste pores) seem to reflect the adaptation of the E. helvum to fruit diets and their ability to switch between diet of fruit, nectar and/or leaves depending on seasonal availability of food type in the challenging tropical West African rain forests habitat.…”

“…Feeding habits and mechanisms are important factors that ensure the success of adaptations of many vertebrates to their environment (Darwish, 2012). The tongue and its papillae structures enhance the ability to feed on nectar and fruit and show significant morphological variations that reflect feeding ecology (Birt et al., 1997; Iwasaki, 2002; Trzcielinska‐Lorych et al., 2009). In this regard, available literature indicates little attention to the morphology of the tongue of megachiropteran species of Africa origin.…”

“…Previous studies on the tongue of some species of nectivory, frugivory and insectivory megachiropterans indicated significant variations in lingual papillae resulting from adaptations to the intake of liquid and semi‐liquid food within the geographical environment (Abayomi et al. 2009; Abumandour & El‐Bakary, 2013; Abumandour, 2014; Emura et al., 2001; Emura et al., 2012; Masuko et al., 2007; Mqokeli & Downs, 2013; Sharma et al., 1999; Taki‐El‐Deen et al, 2013; Trzcielinska‐Lorych et al., 2009).…”

Morphology of the Filiform Lingual Papillae in Porcupine (Hystrix cristata)

“…The morphology and distribution of the lingual papillae has recently been well documented in a wide range of animal species, ranging from reptiles (Abbate et al., 2009) to feral and domestic mammals (Benetti et al., 2009; Jackowiak et al., 2009; Trzcielińska‐Lorych et al., 2009) including rodents such as rats (Iida et al., 1985; Kullaa‐Mikkonen et al., 1987; Iwasaki et al., 1997, 1999), mice (Iwasaki et al., 1987b, 1996; Meisel et al., 1987), hamsters (Fernandez et al., 1978), guinea pigs (Kobayashi, 1990) and flying squirrels (Emura et al., 1999). However, the morphology of the filiform papillae of porcupine has not yet been described before.…”

Comparative evaluation of the ultrastructural morphology and distribution of filiform and fungiform tongue papillae in Egyptian mice, fruit bats and long-eared hedgehogs

“…In addition, it was demonstrated that the filiform papillae form the preliminary pathway of food conveyance which comes into contact with the palate during chewing and deglutition so these papillae possess a good mechanical function. They also supply the tongue with a roughened surface www.acbjournal.org suitable for food movement and grinding [49,50]. Filiform papillae contain no taste buds suggesting that they have no role in taste sensation and have only mechanical function during the masticatory process [50][51][52].…”