Light and scanning electron microscopy of the developing lingual papillae in the green iguana, Iguana iguana

Abstract

ABSTRACT:Reptiles have recently become a popular group of pet animals. A relatively large number of studies on the morphology of the oral cavity and method of feeding in adult individuals have been published. Nevertheless, embryological descriptions of reptile body parts or structures are rare. In this study, we describe the morphology of the developing tongue, in particular its dorsal surface, in pre-hatched green iguanas. Microscopic examination of the oral cavity of early embryos revealed that the tongue was divided into three different areas: apex, corpus and radix. The dorsal lingual surface was smooth and covered by nonkeratinised stratified squamous epithelium with slight prominences in some cases. In the underlying mesenchyme of the tongue, striated muscular tissue was formed. The epithelium thickness was reduced during formation of the lingual papillae and in later stages remained simple cuboidal. No developing taste buds could be recognised in the lingual epithelium.

Histological and morphological observations on tongue of Scincella tsinlingensis (Reptilia, Squamata, Scincidae)

“…Numerous studies have shown that, abundant lingual papillae are found on the dorsal side of the reptiles' tongue (Cizek et al, 2011). Lingual papillae covered with a stratified squamous epithe- lium that with thickness and keratinization in different extent (Smith, 1988), otherwise, also different in shape, size, number and function, all of these determined by the different of habitat, feeding habits and the processing of food (Iwasaki and Miyata, 1985).…”

“…In addition, Crocodilians generally have taste buds in the oral epithelium and lingual epithelium (Ferguson, 1981), and some Testudines have taste buds in the oropharyngeal mucosa (Iwasaki and Kumakura, 1994). Taste buds are not existing in lingual epithelium of T. scincoides and some Testudines (Abbate et al, 2009;Cizek et al, 2011).…”

“…Consequently, the reptiles' tongue has been concerned by scholars, and many related studies have been done on the structure of the tongue of reptiles Mohammed et al, 1998;Mohammed, 1991Mohammed, , 1992Schwenk, 1986;Wassif and Hawary, 1998). These studies show that great variety exist in lingual histology and morphology, especially variation in shape, size, number and function of the dorsal papillae (Cizek et al, 2011). All of these are determined by the different of habitat, feeding habits and the processing of food (Iwasaki and Miyata, 1985).…”

Light and scanning electron microscopy of the tongue of the sand lizard (Lacerta agilis)

“…Some lizards, as well as turtles, cannot protrude their tongue. Despite this fact, the lingual apex of many lizards is forked and the lingual radix also extends distally in the form of two processes [6]. However, the tongue of the rough tailed rock agama (Laudakia stellio) is not forked [16].…”

“…The dorsal surface of the tip of the tongue is smooth in many lizards such as the green anole, Anolis carolinensis [18], blue-tongued skink, Tiliqua scincoides [2], Japanese lizard, Takydromus tachydromoides [13], bearded dragon, Pogona vitticeps [21], Italian lizard, Podarcis sicula [3], rough tailed rock agama, Laudakia stellio [16] and green iguana, Iguana iguana [1,6].…”