Traumatic alterations in the exoskeleton of glyptodonts (Cingulata, Xenarthra) and associated to behavior

Abstract

Alterations in the exoskeleton of glyptodonts have provided valuable information about the behavior of these animals. Studying the exoskeleton of the most known genera of glyptodonts, we found traumatic alterations suggestive of impact provoked by armored parts of their bodies such as the tail. We linked our findings based on the anatomy and biomechanical traits and we used X-rays and digital microscopy to identify the lesions as complementary examination to the macroscopic analysis. Here we present the first records of traumatic alterations in Hoplophorus euphractus and Propalaeohoplophorus australis and we identified more cases of alterations in Panochthus and Glyptodon. The observed alterations were fractures, deformations and perforations with some of them associated with infections. These marks on the carapaces can be associated with caudal tube impacts, and the observed damages in the tails were made by the same nature of impact. The anatomy of the striking tail and the fighting behavior was probably guided by sexual selection, where males in intraspecific combats fought for territory or mates.