Pampatheriidae
Encyclopedia
Pampatheridae is an ancient family, now extinct
, of large armadillo-like plantigrade
armored xenarthra
ns. They are related to Glyptodontidae
, an extinct family of much larger and more heavily armored xenarthrans, as well as to smaller extant armadillo
s (Dasypodidae). However, Pampatheriidae has existed as a separate lineage at least since the middle Eocene
Mustersan
age, 45-48 million years ago. Pampatheres evolved in South America
during its long period of Cenozoic
isolation. Although widespread, they were less diverse and abundant than the armadillos. Holmesina
spread to North America
after the formation of the Isthmus of Panama
as part of the Great American Interchange
. They finally disappeared on both continents in the end-Pleistocene
extinctions
, about 12 000 years ago.
Pampatheres are believed to have attained a weight of up to 200 kg. Like three-banded armadillos
, and unlike glyptodonts, their armored shell was given some flexibility by three movable lateral bands of scute
s. The osteoderm
s (bony plates in the skin comprising the armor) of pampatheres were each covered by a single keratin
ized scute, unlike osteoderms of armadillos, which have more than one scute.
A study of pampathere jaw biomechanics showed that their masticatory muculature 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 grazers
, 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 H. occidentalis, which lived in humid lowlands.
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
, of large armadillo-like plantigrade
Plantigrade
right|151px|thumb|Human skeleton, showing plantigrade habitIn terrestrial animals, plantigrade locomotion means walking with the podials and metatarsals flat on the ground. It is one of three forms of locomotion adopted by mammals...
armored xenarthra
Xenarthra
The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...
ns. They are related to Glyptodontidae
Glyptodontidae
Glyptodonts were large, more heavily armored relatives of extinct pampatheres and modern armadillos.They first evolved during the Miocene in South America, which remained their center of species diversity...
, an extinct family of much larger and more heavily armored xenarthrans, as well as to smaller extant armadillo
Armadillo
Armadillos are New World placental mammals, known for having a leathery armor shell. Dasypodidae is the only surviving family in the order Cingulata, part of the superorder Xenarthra along with the anteaters and sloths. The word armadillo is Spanish for "little armored one"...
s (Dasypodidae). However, Pampatheriidae has existed as a separate lineage at least since the middle Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
Mustersan
Mustersan
The Mustersan age is a period of geologic time within the Eocene epoch of the Paleogene used more specifically with South American Land Mammal Ages. It follows the Casamayoran and precedes the Divisaderan age....
age, 45-48 million years ago. Pampatheres evolved in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
during its long period of Cenozoic
Cenozoic
The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...
isolation. Although widespread, they were less diverse and abundant than the armadillos. Holmesina
Holmesina
Holmesina is a genus of pampathere, an extinct group of armadillo-like creatures that were distantly related to extant armadillos. Like armadillos, and unlike the other extinct branch of Cingulata, the glyptodonts, the shell was made up of flexible plates which allowed the animal to move more easily...
spread to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
after the formation of the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...
as part of the Great American Interchange
Great American Interchange
The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...
. They finally disappeared on both continents in the end-Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
extinctions
Quaternary extinction event
The Quaternary period saw the extinctions of numerous predominantly larger, especially megafaunal, species, many of which occurred during the transition from the Pleistocene to the Holocene epoch. However, the extinction wave did not stop at the end of the Pleistocene, but continued especially on...
, about 12 000 years ago.
Pampatheres are believed to have attained a weight of up to 200 kg. Like three-banded armadillos
Tolypeutes
The genus Tolypeutes contains the two species of three-banded armadillos. They are restricted to South America, mostly Brazil.- Species :There are two recognized species:* Tolypeutes matacus – Southern Three-banded Armadillo...
, and unlike glyptodonts, their armored shell was given some flexibility by three movable lateral bands of scute
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
s. The osteoderm
Osteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...
s (bony plates in the skin comprising the armor) of pampatheres were each covered by a single keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
ized scute, unlike osteoderms of armadillos, which have more than one scute.
A study of pampathere jaw biomechanics showed that their masticatory muculature 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 grazers
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
, 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 H. occidentalis, which lived in humid lowlands.