Named By: Edward Drinker Cope - 1870.
Classification: Chordata, Synapsida, Therapsida, Anomodontia, Dicynodontia, Lystrosauridae.
Species: L. murrayi (type), L. declivus, L. curvatus, L. maccaigi, L. georgi.
Size: Approx 1 meter long.
Known locations: Widespread across southern continents with the main concentration of remains found in South Africa. Other specimens have been recovered from Antarctica, China, India, Mongolia and Russia.
Time period: Late Permian to the Early Triassic.
Fossil representation: Lystrosaurus is one of the most common fossil species dated from the Early Triassic.
in the usual sense, Lystrosaurus had two tusks,
typical of the
dicynodonts. These tusks projected downwards from the maxilla, and
are thought to have been used to dig up the nutritious roots of plants
that grew in the arid climates of the time. It is also thought that
Lystrosaurus had a horny beak for snipping off
vegetation above ground
which would then be ground against a horny second palate in its mouth.
Study of the lower jaw shows that it was adapted to move back and
forth to aid in this grinding process.
The stout body of Lystrosaurus was supported by four legs that were in a semi sprawling position. This means that while Lystrosaurus carried itself up off the ground, the legs would stick out to the sides as opposed to supporting its weight underneath like columns.
Lystrosaurus was exceptionally common in the early Triassic, and may have formed as much of ninety-five per cent of the total known vertebrate population. It is thought that the aftermath of the Permian extinction involved a lack of both competitive herbivorous animals and large predators capable of taking down a fully grown Lystrosaurus caused this, the result of which was Lystrosaurus becoming the dominant land vertebrate of the time.
During the course of its discovery many more species have been attributed to the Lystrosaurus genus, but they are not recognised by all. The huge amount of fossil material that exists for Lystrosaurus means that the total accepted species can and are likely to fluctuate over coming years.