Keichousaurus
Name: Keichousaurus
(keichow lizard).
Phonetic: kay-chow-sore-us.
Named By: Young - 1958.
Classification: Chordata, Reptilia,
Sauropterygia, Nothosauroidea, Pachypleurosauria
Species: K. hui, K.
yuananensis.
Type: Piscivore.
Size: Most known individuals range between 15-30
centimetres long.
Known locations: China.
Time period: Anisian through to the Norian of the
Triassic.
Fossil representation: Specimens are so numerous it
is hard to estimate.
Keichousaurus
looks like a miniature plesiosaur, and indeed many have looked into
the possibility that it may either be a direct ancestor, or
representative of an ancestral form that led to the evolution of the
giant plesiosaurs.
As
well as resembling the
later plesiosaurs, Keichousaurus may have moved
like them too,
using their flattened fore limbs to push themselves along. Study of
the caudal vertebrae also suggests strong muscle attachment, implying
that the tail could have also provided some form of propulsion,
perhaps as a throwback to its earlier terrestrial ancestors.
Because
of these specialised
limbs, it is thought by many that Keichousaurus
would have spent most
of its time in the water. However, there are some specimens that
show a differently developed ulna that could have supported limited
movement on the land. Study of Keichousaurus
individuals of different
ages has also shown aliometric growth, meaning that different body
parts grew at different rates to other parts.
Some
fossils of Keichousaurus
have been recovered with what appear to be young Keichousaurus
inside
of the main specimen. Their position and completion inside of the
main fossil suggest that they are not in the stomach, but are
actually young waiting to be born. This implies that Keichousaurus
was viviparous and gave birth to live young as opposed to laying
eggs. This further reinforces the view that Keichousaurus
was a
primarily marine creature.
Because
Keichousaurus
skeletons are often so well preserved, they make popular collectors
pieces. However, care should be taken as some fossils that are sold
as genuine, are actually reproductions of original fossils. The
reproductions still make nice collectors pieces, but do not warrant
the price tags of the originals. As with anything, try to find a
reputable dealer.
Further reading
- On the new Pachypleurosauroidea from Keichow, south-west China. -
Vertebrata PalAsiatica 2(2-3):72-81 - C. -C. Young - 1958.
- On the new nothosaurs from Hupeh and Kweichou, China. - Vertebrata
PalAsiatica 9(4):337-356. - C. -C. Young - 1965.
- New information on sexual dimorphism and allometric growth in
Keichousaurus hui, a pachypleurosaur from the Middle
Triassic of
Guizhou, South China. - Acta Palaeontologica Polonica 60 (3): 681–687.
- Yifan Xue, Dayong Jiang, Ryosuke Motani, Olivier Rieppel, Yuanlin
Sun, Zuoyu Sun, Cheng Ji & Pengfei Yang - 2013.
----------------------------------------------------------------------------
More marine creatures
 |
 |
 |
 |