Thylacosmilidae is an extinct
family of
metatherian predators, related to the modern
marsupials
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a po ...
, which lived in
South America between the
Miocene and
Pliocene epochs. Like other South American mammalian predators that lived prior to the
Great American Biotic Interchange, these animals belonged to the order
Sparassodonta
Sparassodonta (from Ancient Greek, Greek to tear, rend; and , gen. , '
The comma is a punctuation mark that appears in several variants in different languages. It has the same shape as an apostrophe or single closing quotation mark () in many typefaces, but it differs from them in being placed on the baseline ...
tooth) is an extinct order (biology), order of carnivore, carnivorous metatherian mammals native to South America, related to modern marsupials. They were once con ...
, which occupied the ecological niche of many
eutherian mammals of the order
Carnivora
Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...
from other continents. The family's most notable feature are the elongated, laterally flattened fangs, which is a remarkable evolutionary convergence with other saber-toothed mammals like ''
Barbourofelis
''Barbourofelis'' is an extinct genus of large, predatory, feliform carnivoran mammals of the family Barbourofelidae (false saber-tooth cats). The genus was endemic to North America and Eurasia during the Miocene until its extinction during t ...
'' and ''
Smilodon''.
Taxonomic history
The family Thylacosmilidae was originally erected by Riggs in 1933, to accommodate ''
Thylacosmilus'', found in the Pliocene
Brochero Formation of Argentina. Later, the family was demoted to a subfamily, as Thylacosmilinae, within
Borhyaenidae, a group