The lineage that led to " Thylacosmilus " was the first to split off, in the late Cretaceous.
2.
The family Thylacosmilidae was originally erected by Riggs in 1933, to accommodate " Thylacosmilus ", found in Pliocene strata of Argentina.
3.
Body mass estimates of " Thylacosmilus " suggest this animal weighed between, and one estimate suggesting up to, about the same size as a modern jaguar.
4.
He and his team discovered over 500 fossil vertebrates including seven new species such as the saber-toothed marsupial, Thylacosmilus atrox and flightless terror bird, Andalgalornis ferox.
5.
The third appearance of long canines is " Thylacosmilus ", which is the most distinctive of the saber-tooth mammals and is also easy to tell apart.
6.
Later, with the discovery of fragmentary specimens of new sparassodonts related to " Thylacosmilus " from Miocene and Pliocene strata, Thylacosmilidae was promoted back to familial status.
7.
They also had a flange on the front of the mandible, not as prominent as those on " Thylacosmilus ", that projected downward as long as the canine tooth.
8.
One particularly notable find was the saber-toothed marsupial " Thylacosmilus ", which he found in Late Miocene-age rocks of Argentina in 1927 and named in 1933.
9.
Sparassodonts spanned a wide range of body sizes, from 2.2 pound ( 1 kg ) weasel or civet-like forms to " Thylacosmilus ", which was the size of a leopard.
10.
""'Thylacosmilus atrox " "'is an extinct species of saber-toothed metatherian that inhabited South America from the late Miocene to Piacenzian Entre R�os, and La Pampa Provinces in northern Argentina.
