Himalayasaurus
Name:
Himalayasaurus
(Himalaya lizard).
Phonetic: Him-ah-lay-ah-sore-us.
Named By: Dong - 1972.
Classification: Chordata, Reptilia,
Ichthyosauria, Shastasauridae.
Species: H. tibetensis
(type).
Diet: Carnivore?
Size: Roughly estimated at about 15 meters
long, possibly larger.
Known locations: Tibet, Qomolangma Feng -
Qulonggongba Formation.
Time period: Norian of the Triassic.
Fossil representation: Very fragmentary remains
including partial limbs, vertebrae and teeth.
Himalayasaurus
was named after the Himalaya Mountains where the holotype material
was first discovered. The description of Himalayasaurus
was based
upon very incomplete post cranial remains and most interestingly teeth
that were unlike any other Triassic aged ichthyosaur
that had been seen
at the time. These teeth were larger, more flattened and with
cutting edges, whereas all other previously known Triassic era
ichthyosaurs at that time had smaller and more conical teeth. This
led some to doubt the validity of the Himalayasaurus
genus, which in
term led to Himalayasaurus being labelled as a
nomen dubium.
Then
in 2013 another new ichthyosaur named Thalattoarchon
was formally
described, and this description ended up being the second time that a
Triassic aged ichthyosaur was identified as having unusually large
teeth. In fact, the teeth of Thalattoarchon are
so similar to those
of Himalayasaurus that the only noticeable
difference between them are
the grooves that run across the tooth crowns of the teeth of
Himalayasaurus. In addition to the teeth
similarity, Thalattoarchon
is known to have lived at an earlier time in the Triassic than
Himalayasaurus, which means that while
Himalayasaurus was the first
large toothed Triassic ichthyosaur genus to be discovered, it was not
the first to evolve.
Himalayasaurus
remains a slightly dubious genus because of difficulties in referring
further ichthyosaur remains to the genus, though the identification
of such unique teeth could conceivably help in attributing new
remains. The most recent analysis of the Himalayasaurus
remains has
led to the conclusion that Himalayasaurus was
probably a shastasaurid
ichthyosaur, a type that seems to have been most common during the
Triassic. The partial remains of Himalayasaurus
have been identified
as coming from an individual that has been estimated to be roughly
around fifteen meters in length. This might sound like a bit too
large, but individuals of the relative shastasaurid genus Shonisaurus
have been seen to have easily attained size of fifteen meters long,
while the type genus of the group, Shastasaurus,
was even bigger
than this.
Further reading
- An ichthyosaur fossil from the Qomolangma Feng (Mt. Everest)
region - Gu ji zhui dong wu yu gu ren lei yan jiu suo ji kan
9:7-10 - Z. -M. Dong - 1972.
- The status of Himalayasaurus tibetensis
(Ichthyopterygia). -
Paludicola 2 (2): 174–181 - R. Motani, M. Manabe
& Z. -M. Dong - 1999.
----------------------------------------------------------------------------
Random favourites
 |
 |
 |
 |