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

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.