The subject of the present study was a tongue of the ring-tailed lemur (Lemur catta), which was provided by the Cooperation Research Program of the Primate Research Institute, Kyoto University. Using a scanning electron microscope, we observed the fine structures of the lingual papillae, which are distributed on or just under the surface of the body of the tongue of this animal. We compared our results with other primates and other mammalian species, and discussed the evolution of the papillae from the viewpoint of comparative anatomy.
The filiform and fungiform papillae were observed on the dorsum of the tongue body in the ring-tailed lemur. The filiform papillae are arranged in a circular pattern chracteristic of the primates. Each circle consists of 13-18 cone-like papillae. There are some differences in size and shape of the papillae between the anterior and posterior parts of the tongue. The general morphology is similar both in the epithelial and connective tissue papillae. In contrast, the fungiform papillae show a hemispheric shape on the epithelium, while they are of a cactus-like shape in the connective tissue. This feature of the fungiform papillae is quite similar to those observed in several species of insectivores and lagomorphs.
According to the present study, together with the results by previous authors, it appears that in lemurs, which are classified in prosimians, the filiform papillae show a morphology chracteristic of the order primates, but the fungiform papillae still retain a primitive feature relative to the Anthropoidea.
