Name: Pharyngolepis.
Phonetic: Fah-rin-go-lep-is.
Classification: Chordata,‭ ‬Agnatha.
Diet: Uncertain.
Size: Around‭ ‬10‭ ‬centimetres long.
Known locations: Norway.
Time period: Late Silurian.
Fossil representation: Few specimens.

       Pharyngolepis was a jawless fish that seems to have been intermediate in its development towards a more open water lifestyle.‭ ‬The Anal fin was present,‭ ‬and the main tail lobe bent downwards to form a rudimentary for improved locomotion through the water.‭ ‬However,‭ ‬rather than having pectoral fins,‭ ‬Pharyngolepis only had a pair of spines,‭ ‬and a series of low crested scales than ran down its back instead of a dorsal fin.‭ ‬This‭ ‬means that Pharyngolepis could not swim for extended periods or at high speeds,‭ ‬because without pectoral fins to act as hydroplanes to stabilise pitch,‭ ‬Pharyngolepis would eventually just nosedive towards the bottom.‭ ‬For this reason,‭ ‬Pharyngolepis was probably a slow swimmer that stayed close to the sea floor where it searched for small marine organisms.‭

       A jawless fish with much better swimming adaptations that lived at the same time as Pharyngolepis is Thelodus.


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