Morphological characterization of the laryngeal cartilages of the Bradypus variegatus sloth (Schinz, 1825)

Helen Lylyan da Silva; Priscilla Virgínio de Albuquerque; Cláudio Barboza de  Andrade; Érica Bruna de Andrade  Soares; Marcela Barbosa D'´Emery; Marina Cavalcanti  Pereira; Gilcifran Prestes de Andrade; Apolônio Gomes Ribeiro; Júlio Cézar dos Santos  Nascimento; Joaquim  Evêncio-Neto; Marleyne José Afonso Accioly Lins Amorim

doi:10.21708/avb.2023.17.4.12024

Autores

Helen Lylyan da Silva Universidade Federal Rural de Pernambuco, Department of Biology, Recife-PE, Brazil. https://orcid.org/0009-0009-5568-9515
Priscilla Virgínio de Albuquerque Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0000-0003-0531-7122
Cláudio Barboza de Andrade Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0000-0002-2348-3282
Érica Bruna de Andrade Soares Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0000-0002-4240-8907
Marcela Barbosa D'´Emery Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0000-0001-5000-9597
Marina Cavalcanti Pereira Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0009-0004-2896-1505
Gilcifran Prestes de Andrade Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0000-0001-6347-7242
Apolônio Gomes Ribeiro Universidade Federal da Paraíba https://orcid.org/0000-0001-6730-0209
Júlio Cézar dos Santos Nascimento Universidade Federal Rural de Pernambuco, Department of Animal Science, Recife-PE, Brazil. https://orcid.org/0000-0003-3107-5876
Joaquim Evêncio-Neto Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0000-0001-6026-1390
Marleyne José Afonso Accioly Lins Amorim Universidade Federal Rural de Pernambuco, Department of Morphology and Animal Physiology, Recife-PE, Brazil. https://orcid.org/0000-0002-7113-0377

DOI:

https://doi.org/10.21708/avb.2023.17.4.12024

Resumo

The common sloth, Bradypus variegatus is an arboreal mammal, belonging to the order Pilosa of the Xenarthra superorder. It has a wide geographical distribution in some countries in Central and South America. However, there is a need for anatomical studies on the B. variegatus larynx, as this organ is important for the functioning of the respiratory system and for vocalization. Thus, the objective was to describe macro and microscopically the cartilaginous structures of the larynx of the B. variegatus sloth. For this purpose, 10 specimens were used, obtained after natural death. Of these, six specimens were fixed with 20% formaldehyde and kept in a 30% saline solution tank, being subsequently submitted to dissection and separation of the laryngeal cartilages. In the remaining specimens, fixation took place in 10% buffered formaldehyde with 0.01M sodium phosphate buffer (PBS) and pH of 7.3, followed by the preparation of slides stained with hematoxylin-eosin. Macro and microscopic analysis were performed. The sloth's larynx is at the level of the first cervical vertebrae, and as for its composition, the presence of unpaired cartilages, cricoid, thyroid and epiglottis and pairs, the arytenoids, was verified. All of them of the hyaline type, being observed in the thyroid cartilage, process of endochondral synostosis. The epiglottis and cricoid cartilages showed different morphology in comparison with other mammals. The arytenoids showed very evident corniculate processes. And the thyroid cartilage stood out in size compared to the others.