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.
Known locations: Germany, Solnhofen limestone. France.
Time period: Late Jurassic.
Fossil representation: A few specimens, some more complete than others.
is one of the few known filter feeding pterosaurs, and its name
heads up the group Ctenochasmatidae which includes similar pterosaurs
such as Pterodaustro
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
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.