Meiolania
Name: Meiolania
(Small roamer).
Phonetic: My-oh-lan-e-ah.
Named By: Richard Owen 1886.
Synonyms: Miolania, Ceratochelys.
Classification: Chordata, Reptilia, Testudines,
Cryptodira, Meiolaniidae.
Species: M. platyceps (type),
M.
brevicollis, M. damelipi, M. mackayi.
Diet: Herbivore.
Size: Carapace length for smaller species found on
smaller islands such as M. mackayi about 70
centimetres. Carapace
length for some individuals of larger species from main continent
however could approach 2
meters long. Average total body length for most individuals from the
main Australian continent about 2.5 meters long.
Known locations: Australia and some of the outlying
islands including as New Caledonia, Lord Howe Island and Vanuatu
amongst others. Possibly Viti Levu.
Time period: Oligocene to Holocene. Finally
disappeared around 1 BP (before present era).
Fossil representation: Numerous specimens.
When
first described from fossil skulls, Meiolania
was first thought to
have been a lizard, hence the name which means ‘small roamer’.
This is a reflection to the earlier description of Megalania
(today
known as Varanus
priscus) which means great roamer and was also
named
by Owen in 1859. In time however it was learned that Meiolania
was
actually a terrestrial turtle and one of if not the largest terrestrial
turtle to live.
Meiolania
species come in a number of sizes but smaller specimens are usually
attributed to smaller island populations, something that could be
attributed to insular dwarfism. The larger specimens of Meiolania
are
estimated at up to two hundred and fifty centimetres long, and
although some aquatic turtles such as Archelon
were bigger, Meiolania
is the biggest known land living turtle. The only real rival that
Meiolania has in terms of size is the giant Colossochelys
from Asia
which is estimated between two hundred and fifty and two hundred and
seventy centimetres long.
Although
we know that Meiolania was a turtle we still don’t
know what kind.
Turtles are classed as either being members of the Cryptodira which
fold their necks under their spines, while the Pleurodira group of
turtles fold their necks to their sides. Meiolania
however could not
do either of these things because of the arrangement of spikes on top
of its skull that would have prevented the head from sliding under the
shell. Despite this however, the Meiolaniidae family of turtles
which Meiolania belongs to is still grouped under
the Cryptodira.
Aside
from the large spikes on the head, Meiolania also
had a spiked tail
similar to some tails of the mammalian glyptodonts, and it’s
plausible that these may have been defensive features for protecting
the head and tail extremities from predators. Such adaptations would
have made it difficult for predators to close their mouths around these
spots without getting a mouthful of spikes.
The
disappearance of much of the Pleistocene megafauna is often attributed
to the arrival of humans and in the case of Meiolania
there is actually
strong evidence to support this. In Vanuatu the remains of the
species Meiolania damelipi have been found in the
rubbish dumps of
early human settlements. Of particular note is the fact that most of
these remains are of leg bones which strongly suggests that the body of
the animal was butchered elsewhere, possibly at the site of the kill
and more manageable parts like the legs were brought back for later
consumption. Study of the layers of these rubbish deposits also
points to an event where Meiolania went extinct
only three hundred
years after the first human contact. This fate was nearly shared by
the Gal�pagos tortoise (Chelonoidis nigra) after
the arrival of the
first Europeans on the Gal�pagos Islands.
Further reading
- Notes on the extinct Chelonian Meiolania, with a
record of a new
occurrence. - Records of the Australian Museum 14 (4): 223–242 - C.
Anderson - 1925.
- Meiolania brevicollissp. Nov. (Testudines:
Meiolaniidae): A new
horned turtle from the Australian Miocene. - Alcheringa: an
Australasian Journal of Palaeontology 16 (2): 93–10. - D. Megirian -
1925.
- Megafaunal expression in a land without mammals-the first fossil
faunas from terrestrial deposits in Fiji (Vertebrata: Amphibia,
Reptilia, Aves). - Senckenbergiana biologica 79 (2): 237–242. - T. H.
Worthy, A. J. Anderson & R. E. Molnar - 1999.
- Megafaunal meiolaniid horned turtles survived until early human
settlement in Vanuatu, Southwest Pacific. - Proceedings National
Academy Sciences USA 107 (35): 15512–15516 - A. W. White, T. H. Worthy,
S. Hawkins, S. Bedford, M. Spriggs - 2010.
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