Lasanius
problematicus
Class Agnatha,
Anaspidiformes
Geological
Time: Upper Silurian
Size (25.4
mm = 1 inch): Fish fossil is 32 mm in length on a 52 mm by 22 mm matrix
Fossil Site:
Leshmagow, Scotland
Fossil Code:
UKF237
Price: Sold
Description:
The Anaspids were simple dorso-laterally compressed fish that probably
led a bottom-dwelling existence. Their main common feature was a
jawless mouth. Indeed the name means without jaws. They were mostly
quite small fishes that flourished during the Silurian and Devonian
that then became extinct except for their modern-day relatives the
Lampreys and Hagfishes. The gills opened as a row of holes along
the side of the animal, typically numbering from 6-15. One unusual
example from Canada holds the record for gills at 30 pairs! They
probably behaved much like the lampreys, and most lived in freshwater
environments. This fine example is known as Lasanius. It had an
elaborate array of dorsal scales, not visible in this dorsal example.
This one is quite rare in that it displays features that appear
to be eyes. They are actually posterior to the eyes which would
be on the sides of the body and are known as the otic capsules.
An otic capsule, also known as the bony labyrinth, is the bone surrounding
the organs of balance. This is the first such example of this taxon
I have come across. Additionally the dorsal scales and gill arches
can be seen in life position. Any specimen of the ansapids is highly
prized, so one displaying this much detail will surely be a trophy
piece for any collection.
Also
see: Paleozoic
Fish Fossils
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