Name: Jamoytius.
Phonetic: Jam-oi-te-us.
Named By: Errol White‭ ‬1946.
Classification: Chordata,‭ ‬Hyperoartia.
Species: J.‭ ‬kerwoodi‭ (‬type‭)‬.
Diet: Uncertain.
Size: Around‭ ‬27‭ ‬centimetres long.
Known locations: Scotland.
Time period: Llandovery to Ludlow of the Silurian.
Fossil representation: Few specimens.

       Jamoytius was a jawless fish‭ ‬of the Silurian,‭ ‬though its credibility has in the past been cast in doubt.‭ ‬Several researchers examined the original fossils and rather than interpreting them as the carbonised remains of muscles,‭ ‬they‭ ‬interpreted them as the scales of an anapsid reptile.‭ ‬Later fossil discoveries however,‭ ‬including specimens with the mouth preserved re-conformed White’s original interpretation that Jamoytius was indeed a jawless fish.‭ ‬That said,‭ ‬some past fossil specimens once attributed to Jamoytius have now been found not to belong to the genus.
       For lack of a better description,‭ ‬Jamoytius seems to resemble a modern lamprey in form,‭ ‬and may have lived in a similar manner,‭ ‬rasping away at the body of another fish before latching on and sucking blood from its target.‭ ‬However,‭ ‬hard teeth are so far unknown and so Jamoytius might have been swum around looking for small organisms to suck into its mouth.‭ ‬Jamoytius had an elongated body with long fins along its back and flanks.‭ ‬The jawless mouth of Jamoytius was faced forwards from the front.‭ ‬The position of the mouth makes it less likely that Jamoytius was a detritivore because most fish that lived that way during the Silurian had their mouths on the undersides of the head.

Further reading
- Jamoytius kerwoodi, a new chordate from the Silurian of Lanarkshire [Scotland]. - Geological Magazine. 83 (2): 89–97. - E. I. White - 1946.
- A new interpretation of Jamoytius kerwoodi White - A. Ritchie - 1960.
-‭ ‬New Evidence on Jamoytius kerwoodi White,‭ ‬An Important Ostracoderm From The Silurian of Lanarkshire,‭ ‬Scotland,‭ ‬Alexander Ritchie‭ ‬-‭ ‬1968.
- Taphonomy and Affinity of an Enigmatic Silurian Vertebrate, Jamoytius Kerwoodi White. - Palaeontology. 53 (6): 1393–1409. - Robert S. Sansom Kim Freedman Sarah E. Gabbott Richard J. Aldridge Mark A. Purnell - 2010.


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