Lystrosaurus
Name: Lystrosaurus
(Shovel lizard).
Phonetic: Liss-tro-sore-us.
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.
Type: Herbivore.
Size: Between 0.6 and 2.5 meters long depending upon
the species. Average about 0.9 meters 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.
Lacking teeth 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.
Further reading
- Contributions to the knowledge of the reptiles of the Karroo
Formation. 3. The skull and other remains of Lystrosaurus
putterilli,
n. sp. - Annals of the Transvaal Museum 5:214-216. - E. C. N. Van
Hoepen - 1915.
- Preliminary description of some new lystrosauri. - Annals of the
Transvaal Museum 5:214-216 - E. C. N. Van Hoepen - 1916.
- On two skeletons of Dicynodontia from Sinkiang. - Bulletin of the
Geological Survey of China 14:483-517 - C. C. Young - 1935.
- On some new genera and species of fossil reptiles from the Karroo
Beds of Graaff-Reinet. Annals of the Transvaal Museum 20:157-192 - R.
Broom - 1940.
- On the genus Lystrosaurus Cope. - Transactions of
the Royal Society
of South Africa 33(1):107-120 - A. S. Brink - 1951.
- Lystrosaurus primitivus, sp. nov. and the origin of the genus
Lystrosaurus. - Annals and Magazine of Natural
History 7:407-426 - M.
J. Toerien - 1954.
- [Preliminary report of a new species of Lystrosaurus
of Sinkiang]. -
Vertebrata PalAsiatica 8(2):216-217 - A. L. Sun - 1964.
- The first Lystrosaurus find from the territory of
the European part
of the USSR. - Palaeontologicheskiy Zhurnal 4:140-142 - N. N.
Kalandadze - 1975.
- Lystrosaurus georgi, a dicynodont from the Lower
Triassic of Russia.
- Journal of Vertebrate Paleontology 25 (2): 402–413. - M. V. Surkov,
N. N. Kalandadze, M. J. Benton - 2005.
- Lystrosaurus species composition across the Permo–Triassic boundary
in the Karoo Basin of South Africa. - Lethaia 40 (2): 125–137. - J.
Botha & R. M. H. Smith - 2005.
- Cranial variability, ontogeny and taxonomy of Lystrosaurus
from the
Karoo Basin of South Africa. - Amniote paleobiology. Perspectives on
the Evolution of Mammals, Birds, and Reptiles,. University of Chicago
Press. pp. 432–503. - F. E. Grine, C. A. Forster, M. A. Cluver
& J. A. Georgi - 2006.
- Evidence of torpor in the tusks of Lystrosaurus from the Early
Triassic of Antarctica. - Communications Biology. 3 (1): 471. - Megan
R. Whitney & Christian A. Sidor - 2020.
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