Microscopic structure of the tongue in the lesser hedgehog tenrec ( Echinops telfairi , Afrosoricida) and its relation to phylogenesis

Microscopic structure of the tongue in the lesser hedgehog tenrec ( Echinops telfairi , Afrosoricida) and its relation to phylogenesis:

Abstract

The tongue of the lesser hedgehog tenrec (Echinops telfairi) was evaluated by light and scanning electron microscopy. Dorsal and lateral surfaces of the tongue were densely covered with various types of lingual papillae. Two types of mechanical papillae (filiform and conical) and two types of sensory papillae (fungiform and vallate) were observed. Rostrocaudally, the number of spikes in filiform papillae increased. Filiform, crown-like papillae were found on the radix, as well as large conical papillae with a wide base and a caudally bent single spike. Fungiform papillae were scattered in four rows on the dorsal surface. Three vallate papillae in inverse triangular layout were developed in the area of the lingual radix. Taste buds were found in the sensory papillae, i.e., fungiform and vallate. The lingual glands were predominantly seromucous. These glands were evenly scattered from the caudal portion of the lingual apex to the lingual radix. Purely serous glands were localized close to vallate papillae. A histochemical analysis of glands was performed. Results were compared to the Afrotheria (tenrec’s relatives) and Eulipotyphla (animals with similar feeding habits to tenrecs). This study is the first description of the lingual morphology in the member of the Order Afrosoricida. Moreover, it compares the effect of the phylogenetic relation to the effect of the feeding habits on the lingual morphology.