Ultrastructural comparison between the tongue of two reptilian species endemic in Egyptian fauna; Bosc's fringe‐toed lizard Acanthodactylus boskianus and Sinai fan‐fingered gecko Ptyodactylus guttatus

Abstract

The current observations focused on the ultrastructure comparison between the tongue of two reptile species endemic the Egyptian fauna; Bosc's fringe‐toed lizard Acanthodactylus boskianus and Sinai fan‐fingered gecko Ptyodactylus guttatus to exhibit the relationship between the lingual epithelium and its function according to their specific feeding strategy. A. boskianus possessed triangular elongated tongue with bifurcated tapering apex and wide base while; the P. guttatus had a triangular flattened tongue with conical shallow bifurcated apex and broad base. The ventral surface of the lingual apex of A. boskianus had transverse while in P. guttatus had two oval pads and median ventral groove. Both surfaces of the tongue of both examined species are covered by stratified squamous epithelium with great variability of degree of keratinization. The dorsal epithelium formed flattened and conical filiform papillae in A. boskianus, while in P. guttatus formed cylindrical papillae, conical, and tall filiform ones. Few taste buds are observed on the fore‐tongue but increase on the mid‐tongue of A. boskianus, while in P. guttatus, numerous taste buds are distributed on the fore‐tongue and mid‐tongue. Both surfaces of the laryngeal mound of both examined species provided with numerous of cilia and orifices of laryngeal gland. The present results confirmed that the tongue of A. boskianus acts as a chemoreceptor organ to follow pheromone trails of prey and mates. While in P. guttatus the tongue may play an important role in the feeding mechanism and act as a chemoreceptor organ.

Scanning electron microscopic and histological features of the oral cavity of the Egyptian tortoise (Testudo kleinmanni)

“…The current histological investigation into the Egyptian tortoise tongue reveals that the dorsal surface is covered with keratinized stratified squamous epithelium and the keratinized layer extends to cover the lingual papillae, as reported previously in Egyptian tortoise, rat and bat (Al-Zahaby et al, 2018;Massoud & Abumandour, 2019. The stratified squamous lining epithelium of the dorsal lingual surface of the currently examined species is similar to that observed in; the juvenile Hawksbill turtle (Iwasaki, Asami, & Wanichanon, 1996a), the juvenile Pacific Ridley turtle (Iwasaki, Wanichanon, & Asami, 1996) and Bosc's fringe-toed lizard and Sinai fan-fingered gecko (Gewily et al, 2021). However, it is in contrast with the reports of previous authors (Iwasaki, 1992;Iwasaki, Asami, & Wanichanon, 1996b)in the freshwater turtle and the softshell turtle, in which the presence of the stratified cuboidal epithelium was reported.…”

“…Meanwhile, a heart‐shaped tongue is described in the semiaquatic giant Asian pond turtle (Lintner et al, 2012). The segmentation of the tongue into three portions (fore‐, mid‐ and hindtongue with caudolateral lingual wings) has been observed in numerous reptile species (Gewily et al, 2021). The triangular tongue is also described in other reptile species (Abbate et al, 2008; Abbate et al, 2020; Gewily et al, 2021)in Leopard Gecko, green iguana, Bosc's fringe‐toed lizard and Sinai fan‐fingered gecko, while the V‐appearance of the tongue was observed in the blue‐tongued lizard(Abbate et al, 2009).…”

“…The four upper and lower parts of the oral cavities with their lips, tongues, laryngeal entrance and palates from the Egyptian tortoises ( Testudo kleinmanni ) were prepared for the SEM techniques (Gewily et al, 2021). The samples (lips, tongue with their laryngeal entrance, and palates) were rinsed in 2.0% glutaraldehyde dissolved in 0.1 M phosphate buffer at pH 7.4.…”

“…Most published data focused on describing the lingual structure and its papillae in various reptilian species (El‐Mansi, Al‐Kahtani, Abumandour, Ezzat, & El‐Badry, 2020; Gewily et al, 2021), with few data on the turtle species (Iwasaki, Asami, & Wanichanon, 1996b; Iwasaki, Wanichanon, & Asami, 1996; Lintner et al, 2012) meanwhile, there are scanty data describing the tongue of the Egyptian tortoises in Egyptian nature (Al‐Zahaby et al, 2018). Furthermore, the anatomical description of the palate is the most ignored part of the oral cavity.…”

Structural and functional adaptation of the lingual papillae of the Egyptian fruit bat (Rousettus aegyptiacus): specific adaptive feeding strategies

“…Then, samples were sectioned in 5 microns using Leica rotatory microtome (RM 20352035; Leica Microsystems, Wetzlar, Germany) and stained by haematoxylin and eosin according to Suvarna et al [58] to demonstrate the general histological structure. Extra sections were stained by Masson's trichrome [21,39] to visualise collagen and muscle fibres.…”