Lasanius Jawless Fish Fossil

with Rare Organ Preservation

Lasanius problematicus

Class Agnatha, Order Anaspidiformes

Geological Time: Upper Silurian

Size: Fish fossil is 21 mm in length (if straight) on a 35 mm by 25 mm matrix

Fossil Site: Leshmagow, Scotland

Fossil Code: UKF261

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, visible in this lateral example. This one is quite rare in that it displays features that appear to be eyes. This is the first such example of this taxon I have come across preserving also the dorsal scales and gill arches 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

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