Lasanius Silurian Agnathan Jawless Fossil Fish

with Rare Organ Preservation

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


Silurian Fossil Fish LasaniusDescription: 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.Silurian Fossil Fish Lasanius 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

Fish Fossils for Sale

click to enlarge

Silurian Fossil Fish Lasanius

Silurian Fossil Fish Lasanius

Silurian Fossil Fish Lasanius


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