Tail blow energy and carapace fractures in a large glyptodont (Mammalia, Xenarthra)

Glyptodonts had muscular tails terminating, in many cases, with a rigid bon y sheath which, in Doedicurus and Panochthus, was a formidable club. Some c arapaces show fractures which have been interpreted as resulting from intra specific fights. We estimate the energy that the tail muscles could have su pplied for a blow and the energy required to fracture the carapace, and obt ain results of the same order of magnitude. Thus it is not unreasonable to interpret the observed damage as resulting from fights. A space between the thoracic and lumbar vertebral column and the carapace may have been occupi ed by a fatty pad which would have served as a protective cushion, reducing the force of impacts. (C) 1999 The Linnean Society of London.