Pterodaustro
Name:
Pterodaustro
(Southern wing).
Phonetic: Teh-roe-daws-trow (The P is silent and
not pronounced).
Named By: Jos� Bonaparte - 1969.
Classification: Chordata, Reptilia,
Pterosauria, Pterodactyloidea, Ctenochasmatidae.
Species: P. guinazui (type),
P.
sp.
Type: Filter feeder.
Size: 2.5 meter wingspan.
Known locations: Argentina, San Luis Privince -
Lagarcito Formation. Chile - Santa Ana Formation.
Time period: Albian of the Cretaceous.
Fossil representation: Over 750 known individual
specimens.
The
discovery of Pterodaustro was a fantastic find,
as not only was it
the first pterosaur
to be discovered in South America, here was a
pterosaur that filtered for food in a similar manner to a modern day
flamingo. This is evidenced by the strongly upwards curing beak that
instead of having more normal pterosaur teeth, Pterodaustro
had
a series of several hundred bristle like teeth that extended upwards
from the lower jaw. The upper jaw did not have these bristle teeth,
but could be closed without contacting or damaging them.
This
jaw arrangement, unusual amongst the pterosaurs, would have allowed
Pterodaustro to scoop up a beak full of water that
contained food
sources such as invertebrates and plankton. The bristle teeth would
allow the water to drain out while keeping small invertebrates inside
so that they could be swallowed. The presence of small globular teeth
in the upper jaw suggests that the invertebrates were probably mashed
before they were swallowed.
Another
first for Pterodaustro is the presence of gizzard
stones. Considering
a diet of small invertebrates, these stones may have spilt and broken
the hard exoskeletons of the invertebrates to allow for more efficient
digestion. They may however simply have been swallowed along with its
food, as only a small number of specimens show these stones.
Because
flamingos have the same food sources, they also absorb their pink
pigment from their food, and because of this, it has been suggested
that Pterodaustro may have also had a pink hue to
its body. However a 2005 study by Shawkey and Hill has cast serious
doubt upon the idea that Pterodaustro may have been
pink as the result
of chosen diet.
The
scleral rings of Pterodaustro indicate a nocturnal
lifestyle. This
may be to avoid feeding competition with other creatures, or avoid
daytime predators that would have had an easy time spotting a pink
Pterosaur. It may have also simply been a case of its food supply
being more plentiful at night, or even a combination of these things.
Because
of the huge number of discovered remains, the growth cycle of
Pterodaustro can be easily established. The
fastest period of growth
took place over the first two years, and in this time the individual
would reach up to half its full size. It is then thought that they
reached reproductive maturity, although they would still continue to
grow for up to a further five years until fully grown. A fossilised
Pterodaustro egg, sixty millimetres long and
twenty-two millimetres
wide has also been found to contain a Pterodaustro
embryo inside.
Further reading
- Pterodaustro guinazui gen. et sp. nov.
Pterosaurio de la Formacion
Lagarcito, Provincia de San Luis, Argentina y su significado en la
geologia regional (Pterodactylidae) [Pterodaustro guinazui
gene. et sp.
nov. Pterosaur of Lagarcito Training, Province of San Luis, Argentina
and its significance in regional geology (Pterodactylidae)]. - Acta
Geologica Lilloana 10: 209–225. - Jose F. Bonaparte - 1970.
- The design of mineralised hard tissues for their mechanical
functions. - Journal of Experimental Biology 202 (23): 3285–3294. -
John D. Currey - 1999.
- Argentinian unhatched pterosaur fossil. - Nature 432 (7017): 571–572.
- L. M. Chiappe, L. Codorni�, G. Grellet-Tinner & D. Rivarola -
2004.
- Carotenoids need structural colours to shine. - Biology Letters 1
(2): 121–4. - M. D. Shawkey & G. E. Hill - 2005.
- Developmental growth patterns of the filter-feeder pterosaur,
Pterodaustro guinazui. - Biology Letters 4 (3):
282–285. - A. Chinsamy,
L. Codorni� & L. M. Chiappe - 2008.
- First occurrence of gastroliths in Pterosauria (Early Cretaceous,
Argentina). - XXIV Jornadas Argentinas de Paleontolog�a de Vertebrados.
- L. Codorni�, L. M. Chiappe, A. Arcucci & A. Ortiz-Suarez -
2009.
- The first pterosaur 3-D egg: Implications for Pterodaustro
guinazui
nesting strategies, an Albian filter feeder pterosaur from central
Argentina. - Geoscience Frontiers. - G. Grellet-Tinner, M. Thompson, L.
E. Fiorelli, E. S. Arga�araz, L. Codorni� & E. M. N.
Hechenleitner - 2014.
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