Pampatheriidae ("Pampas beasts") is an Extinction family of large Cingulata related to . They first appeared in South America during the mid-Miocene, and Holmesina and Pampatherium spread to North America during the Pleistocene after the formation of the Isthmus of Panama as part of the Great American Interchange. They became extinct as part of the end-Pleistocene extinction event, about 12,000 years ago.
Taxonomy
The placement of the
Eocene genus
Machlydotherium in the family is considered doubtful. The oldest undoubted member of the group is
Scirrotherium from La Venta, Colombia, dating to the mid-Miocene.
Analysis of ear morphology suggests that they are most closely related to the much larger
Glyptodont, which genetic evidence indicates is nested with modern armadillos as part of the family
Chlamyphoridae, which by extension also places pampatheres within this group.
Phylogeny after Tambusso et al. (2021):
Description
Pampatheres are believed to have attained a weight of up to . Like
Tolypeutes, and unlike
, their armored shell was given some flexibility by three movable lateral bands of
.
The
(bony plates in the skin comprising the armor) of pampatheres were each covered by a single
scute, unlike osteoderms of armadillos, which have more than one scute.
A study of pampathere jaw biomechanics showed that their masticatory musculature was more powerful and more adapted for transverse movements than that of armadillos, leading to the conclusion that much of their diet was coarse vegetation. They are thought to have been primarily
grazing, unlike armadillos, which are omnivorous or insectivorous.
The variation between species in the expression of adaptations for grinding coarse vegetation correlates with the aridity of their habitat; such adaptations are most pronounced in
Pampatherium typum, which lived in the arid
Pampas, and least pronounced in
Holmesina occidentalis, which lived in humid lowlands.
Distribution
Pampatheres were widely distributed across South America during the Pleistocene ranging from northern Argentina, eastwards to northeastern Brazil, and westwards to Colombia and Peru.
As part of the Great American Interchange, pampatheres dispersed northwards into Central and North America, with members of the genus
Holmesina reaching the United States, as far north as Kansas, and as far east as Florida and South Carolina.
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