Comparative morphology of tongue surface in Neotropical aerial insectivore bats (Mammalia: Chiroptera)

Abstract

Comparative morphological characters in Neotropical bats are mostly restricted to external and cranio-dentary complexes, and few studies focusing on other morphological complexes have been carried out. In the case of tongue morphology, comparative analyses of the structure have been restricted to the superfamily Noctilionoidea with a wide range of diets, and Molossidae, a strictly aerial insectivore family. In this paper, we studied the morphology of tongue papillae in 10 aerial insectivore Neotropical bat species, representing six families (Emballonuridae, Furipteridae, Thyropteridae, Mormoopidae, Natalidae, and Vespertilionidae), and data from the previous study of Molossidae were compared. We studied tongues in light and scanning electron microscopes following material preparation protocols. We observed two types of sensitive papillae, circumvallate and fungiform, the latter at times presenting a groove surrounding the papillae. Nine mechanic types were observed, one of them, which we called flaky-like, not hitherto described. All Vespertilionoidea families (Vespertilionidae, Natalidae, and Molossidae) presented, as diagnosing characters, fungiform papillae distributed throughout the tongue, as well as anteriorly at the dorsum, and scale-like papillae on the medial lobe directed laterally and anteriorly. Emballonuridae showed the simplest tongue morphology regarding the presence and abundance of some papillae. Families composing the clade Furipteridae + Thyropteridae + Mormoopidae presented small and non-grooved fungiform papillae, and mechanical bifid papillae were absent. In summary, this study has provided additional traits (putative synapomorphies) of the bat tongue to support the clades on the current bat phylogeny.