Morphological features of lower respiratory tract of nine-banded armadillo (Dasypus novemcinctus, Linnaeus, 1758).

The nine-banded armadillo (Dasypus novemcinctus) is a mammal of the Xenarthra Superorder, which inhabits Central, South and North America. Few morphological descriptions are observed in this species, including the respiratory tract; therefore, the objective of this study was to describe morphologically the lower respiratory tract of the nine-banded armadillo. Five animals were dissected, and the macroscopic and microscopic aspects were analysed. In the anatomical analysis, the perfusion technique was performed with vinyl acetate and the fragments of tissue from respiratory organs (trachea, bronchi, bronchioles and pulmonary lobes) were stained with haematoxylin-eosin for visualization under optical microscopy. Containing about 30 cartilage rings, the trachea is lined internally with ciliated pseudostratified epithelial tissue. The lungs are subdivided into lobes by deep interlobar fissures, with two lobes in the right lung and three lobes in the left lung. Microscopically, the primary, secondary and tertiary bronchi have non-ciliated pseudostratified epithelium with goblet cells. It was found that macro- and microscopically the respiratory tract of this species is similar to existing xenarthras and other excavator animals. These data provide subsidies for the clinic and preservation of this species.