Exceptional preservation of tracheal rings in a fossil mammal: the case of Panochthus sp. (Xenarthra; Glyptodonti

ZAMORANO M.; GONZÁLEZ RUIZ L. R.; ºººººººººº

Congreso; 1st Palaeontological Virtual Congress; 2018

mammals, the trachea is a relatively non-collapsible tube that extends from the cricoid cartilage of the larynx to its bifurcation, where the bronchial tree begins. The skeleton of the trachea is formed by C-shaped hyaline tracheal cartilages (?tracheal rings?) that form a tube that connects the larynx with the bronchial tree, providing air flow to and from the lungs for respiration. In this contribution, we describe the presence of ?tracheal rings? in a glyptodont (Cingulata), an extremely rare occurrence in a fossil mammal. The exceptional preservation of specimen MHM-P87, assigned to Panochthus sp. (Glyptodontidae), allowed us to identify elements of the hyoid apparatus, fragments of the cricoid cartilage, and several tracheal rings. The specimen also includes mandible, postcranial bones, and the dorsal carapace, and was found in the margin of the Salado River (General Belgrano, Buenos Aires Province, Argentina; 111135° 45´ 5.52" S-58° 37´ 35.96" W) in sediments of the Luján Formation dated between ca. 14 and 12 ky BP (late Pleistocene). Twenty-three fragments of tracheal rings were found, and most of them (16/23) correspond to lateral segments that vary from 19 to 54 mm in length and 6 to 8 mm in width. Some of the fragments correspond to ventral portions of rings, and some of them (the largest) could correspond to the cricoid cartilage. We reconstructe more than one tracheal ring and compared it with tracheal rings of common domestic animals (e.g., dog, horse, sheep); the specimens are transversely ovoid in shape and very similar to those of the horse in general aspect. Although there are no studies on this structure, with future analyses we could obtain information about paleobiological implications of this structure in 0