Brachauchenius
Name:
Brachauchenius
(Short neck).
Phonetic: Brak-ow-ken-ee-us.
Named By: Samuel Wendell Williston - 1903.
Classification: Chordata, Reptilia,
Sauropterygia, Plesiosauria, Pliosauridae.
Species: B. lucasi (type).
Diet: Carnivore.
Size: Skull about 90 centimetres long.
Known locations: USA, Kansas. Colombia. England?
Time period: Barremian through to the Turonian of
the Cretaceous.
Fossil representation: Skulls, mandibles (lower
jaws) as well as partial post cranial remains such as vertebrae.
Brachauchenius
was once regarded as one of the largest pliosaurs,
and this was down to
the addition of a skull measuring 170 centimetres in length to the
genus.
However, in 2013 this skull was used to establish a new genus called
Megacephalosaurus.
This in turn has led to a size revision for
Brachauchenius, one based upon the holotype skull
size which is 90
centimetres in length. This means that the Brachauchenius
genus is now
though to have been much small than before, but still not something you
would want to get on the wrong side of.
Brachauchenius
represents one of the last of the pliosaurs known to have swum in
the Mesozoic oceans. The heyday for the pliosaurs seems to have been
around the end of the Jurassic when others such as Pliosaurus
and
Liopleurodon
were at their most
numerous. As the
Cretaceous continued however new competition in the form of mosasaurs
such as Tylosaurus
and Hainosaurus
displaced the pliosaurs from their
position as the top predators of the oceans.
Like
its predecessors Brachauchenius would have
specialised in hunting
prey such as fish, but possibly some other marine reptiles too. Long
associated with the Western Interior seaway
(specifically Kansas) the discovery of Brachauchenius
in Colombia,
South America, proves that Brachauchenius was
certainly not
restricted to the United States. This is not all that surprising when
you consider that a population of large predators like Brachauchenius
cannot concentrate in one area otherwise they would exhaust the local
supply of prey species. As such these predators have to spread out in
order to maintain a balance between them and their prey so that
their own species can survive.
Additionally
the Colombian material not only extends the geographical range of
Brachauchenius, but the temporal range as well.
Further,
Brachauchenius is one of the first of the large
short necked pliosaurs
to appear in the Cretaceous after an apparent disappearance between the
end of the Jurassic and early-mid Cretaceous. Of course this does not
mean to say that these pliosaurs disappeared completely just to
reappear later, just that their remains are not as well documented.
Further reading
- The skull of Brachauchenius, with special
observations on the
relationships of the plesiosaurs. - United States National Museum
Proceedings 32: 477-489. - S. W. Williston.
- Considerations on a Brachauchenius skeleton
(Pliosauroidea) from the
lower Paja Formation (late Barremian) of Villa de Leyva area
(Colombia). - Fossil Record - Mitteilungen aus dem Museum f�r
Naturkunde in Berlin 8 (1): 37-51. - O. Hampe - 2005.
- Historical note on the 1884 discovery of Brachauchenius
lucasi
(Plesiosauria; Pliosauridae) in Ottawa County, Kansas. Transactions of
the Kansas Academy of Science 110 (3/4): 255-258. - M. J. Everhart -
2007.
- A new Cretaceous pliosaurid (Reptilia, Plesiosauria) from the Carlile
Shale (Middle Turonian) of Russell County, Kansas. - Journal of
Vertebrate Paleontology 33(3):613-628. - B. A. Schumacher, K. Carpenter
& M. J. Everhart - 2013.
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