Ctenochasma
Name:
Ctenochasma
(Comb jaw).
Phonetic: Sten-oh-chaz-ma.
Named By: Christian Erich Hermann von Meyer -
1852.
Classification: Chordata, Reptilia,
Pterosauria, Pterodactyloidea, Ctenochasmatidae.
Species: C. roemeri (type),
C.
elegans, C. taqueti.
Type: Filter feeder.
Size: 25 centimetre wingspan for smaller species.
Known locations: Germany, Solnhofen limestone.
France.
Time period: Late Jurassic.
Fossil representation: A few specimens, some more
complete than others.
Ctenochasma
is one of the few known filter feeding pterosaurs,
and its name
heads up the group Ctenochasmatidae which includes similar pterosaurs
such as Pterodaustro
and Unwindia.
The method of pterosaurs filter
feeding is quite simple as instead of having the large needle like
teeth associated with catching fish and insects, pterosaurs like
Ctenochasma have several hundred smaller and finer
teeth creating a
comb. All Ctenochasma would have to do is scoop
up a beak full of
water and allow it to drain out though its teeth. The teeth would
filter out things like aquatic invertebrates leaving Ctenochasma
with a
mouthful of food.
Unlike
Pterodaustro which only had teeth for the bottom
jaw, Ctenochasma
had
specialised teeth in the top jaw as well, and when brought together
they could have formed a loose 'basket'. This could suggest that
while Ctenochasma employed filter feeding as its
chosen strategy, it
may have had slightly different prey to others of its kind. One
interesting feature that both Ctenochasma and Pterodaustro
do share
are similar scleral rings that indicate both of them lived
nocturnal lifestyles. This is often explained as niche partitioning,
for the nocturnal pterosaurs to avoid direct competition with other
pterosaurs that are active during the daytime. However the fact that
both of these pterosaurs were nocturnal may be explained by a greater
more abundant food supply at night.
Phytoplankton
actually has its greatest concentration several meters below the water
surface because when it is too close to the top it can actually become
damaged or killed off by stronger ultraviolet radiation from the sun.
This is why phytoplankton often rises nearer the surface at night,
and when it rises, all the other small aquatic vertebrates that feed
on it also rise up with it, into the range of any filter feeding
pterosaurs that might be waiting.
Further reading
- Un crane de Ctenochasma (Pterodactyloidea) du Portlandien infe rieur
de la Haute-Marne, dans les collections du Musee de St-Dizier. -
Comptes Rendus de l'Acad�mie des Sciences. 174: 362–364. - P. Taquet -
1972.
- Description of the skull of a Ctenochasma (Pterosauria) from the
latest Jurassic of eastern France, with a taxonomic revision of
European Tithonian Pterodactyloidea. - Journal of Vertebrate
Paleontology. 24 (3): 542–554. - S. Jouve - 2004.
- A review of the pterosaur Ctenochasma: taxonomy and ontogeny. - Neues
Jahrbuch f�r Geologie und Pal�ontologie, Abhandlungen 245:23-31.- S. C.
Bennet - 2007.
----------------------------------------------------------------------------
More about pterosaurs!
|
|
 |
 |