Tongue papillae morphology of brown-throated sloth Bradypus variegatus (SCHINZ, 1825)

Abstract

The Bradypus variegatus inhabits the forests of South America and feeds from leaves, branches and sprouts from different plants. Due to its diet and the lack of literature on the morphological aspect of Xenarthras, five Bradypus variegatus tongues from animals which died from natural causes were evaluated, and they came from Pará State Museum Emílio Goeldi and were donated to the Laboratory of Animal Morphological Research (LaPMA) from UFRA, for revealing the different types of papillae and epithelial-connective tissue. Macroscopically, the tongues presented elongated shape, rounded apex, body, root, median sulcus in the root's apex, and two vallate papillae. The mucous membrane of the tongue revealed a keratinized stratified pavement epithelium, while the ventral surface of the tongue was thin and smooth, not provided with any type of papillae. However, the dorsal surface of the tongue was irregular with the presence of three types of papillae: filiform, fungiform and vallate papillae. The filiform papillae found were of a simple type, presenting a rounded base, irregularly distributed with a larger concentration and development on the tongue's apex and body. The fungiform papilla showed a practically smooth surface with irregular format, with the presence of gustatory pores; these were found all over the dorsal surface, with larger concentration at the rostral part of the apex. Only two vallate papillae were observed disposed in the root of the tongue, surrounded by a deep groove, and revealing several taste buds. The tongues from Bradypus variegatus presented gustatory papillae similar to the ones described for other Xenarthras species and wild mammals. Keywords: morphology, lingual papillae, Bradypus variegatus RESUMO A Bradypus variegatus habita florestas da América do Sul e alimenta-se de folhas, ramos e brotos de várias plantas. Em decorrência de sua dieta, bem como da escassez de literatura sobre aspectos morfológicos dos Xenarthras, avaliaram-se cinco línguas de Bradypus variegatus, que foram a óbito por causas naturais, provenientes do Museu Paraense Emílio Goeldi e doados ao Laboratório de Pesquisa

Morphology of the tongue of Vermilingua (Xenarthra: Pilosa) and evolutionary considerations

“…The axis of each circumvallate papillae is oriented obliquely to the main axis of the tongue in Cingulata, but not in Pilosa. By our observations of Myrmecophagidae and C. unicinctus and the data in the literature (Benetti et al, ; Cupa‐Caparo, ; Kubota et al, ; Martins et al, ), it is possible to conclude that the circumvallate papillae of armadillos and sloths present more taste buds when compared to anteaters, in agreement with the conclusion of Kubota et al () that the tongue in anteaters may be poorly developed for taste function.…”

“…The presence of two circumvallate papillae is consistent among xenartrans (Rapp, ; Sonntag, ). Some studies (Mayer, ; Münch, ; Silva et al, ) reported from three to eight circumvallate papillae in xenarthrans, but our observations and literature review suggest that these reports are mistaken or refers to a rare condition, not observed in the majority of the studies about the tongue of Xenarthra (Benetti et al, ; Dingler, ; Martins et al, ; Morais & Watanabe, ; Rapp, ; Sonntag, ; Sonntag & Duncan, ). The axis of each circumvallate papillae is oriented obliquely to the main axis of the tongue in Cingulata, but not in Pilosa.…”

“…Conversely, as the armadillos also use their tongue in processing varied types of food and uses mastication, their tongue is not as wormlike as in the obligatory myrmecophagous anteaters. In sloths, the tongue has a rounded tip, with lateral borders almost parallel through much of its length and oval in cross section, resulting in a compact, thick tongue (Benetti, ; Benetti et al, ; Martins et al, ; Rapp, ; Sonntag, ; Sonntag & Duncan, ). This conforms with the spatulate type of tongue (Type I), capable of intense intra‐oral manipulation of the food, required for processing the tough vegetal material which constitutes the greater part of the diet of folivorans.…”

“…There are some studies detailing the tongue morphology of Xenarthra in general (Bradley, ; Dingler, ; Gmelin, ; Grassé, ; Kühlhorn, ; Mayer, ; Münch, ; Oppel, ; Owen, ; Rapp, ; Sonntag, ; Stadtmüller, ; von Bayern, ), and others focusing on the tongues of Cingulata (Boulart & Pilliet, ; Ciuccio, Estecondo, & Casanave, ; Cupa‐Caparo, ; Estecondo, Codón, & Casanave, ; Morais & Watanabe, ; Morais, Watanabe, & König, ; Tuckerman, ; Watanabe, Morais, Yokoyama, Inokuchi, & Hamassaki, ), and Folivora (Benetti, ; Benetti et al, ; Martins et al, ; Sonntag, ; Sonntag & Duncan, ), which allows for a comparative analysis of tongue anatomy and histology in the group.…”

CARACTERÍSTICAS ANATÔMICAS DAS PAPILAS LINGUAIS DE Leopardus pardalis (Carnivora: Felidae) (Linnaeus, 1758)

“…A língua dos exemplares estudados assim como em outras espécies de mamíferos selvagens como Panthera pardus saxicolor (leopardo) (SADEGHINEZHAD et al, 2017), Panthera tigris altaica (tigre) (EMURA et al, 2004), Suricata suricatta, (suricato) (ERDOGAN et al, 2016) Cerdocyon thous (mão-pelada) Chrysocyon brachyurus (lobo-guará) (LIMA, 2015) apresentou as três regiões usuais deste órgão: raiz, corpo e ápice. Observou-se ainda a existência de um sulco mediano, que dividia o dorso em duas metades simétricas direita e esquerda, como em Cuniculus paca (paca) (BERALDO-MASSOLI et al, 2013), Nasua nasua (quati) (SOUZA et al, 2012), Bradypus torquatus (preguiça-comum) (MARTINS et al, 2014) e sagui-de-tufo-preto (BRANCO et al, 2012 (CORRÊA et al, 2012;LIMA, 2015) e Kerodon rupestris (mocó) (SANTOS et al, 2015) e Callithrix penicillata (sagui-de-tufo-preto), já as funções destas papilas estão relacionadas com percepções de caráter gustativo (DELMANN ; BROWN 2003).…”