Lasanius problematicus Anaspid Fossil Fish

from Silurian Scotland

Lasanius problematicus

Class Agnatha, Order Anaspidiformes

Geological Time: Upper Silurian (385 Million Years Old)

Size: 27 mm

Fossil Site: Seggholm, Muikirk, Ayrshire, Scotland

Lasanius problematicus silurian fossil fishDescription: 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 Lasaniusfor 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 that are seen here quite clearly. Complete examples of the Anaspida are quite rare, with few ever available to the general public All the diagnostic features of the taxon are displayed within this high-quality specimen that has recently been obtained from a 50 year old collection.

Also see: Paleozoic Fish Fossils

click fossil pictures to enlarge


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