#thelodus

[sinasinasinas]

Thelodus scoticus/Loganellia scotica. Mutationella podolica Community , Lower Devonian.

Ormoceras sp. , an actinocerid nautiloid that was found in the same formation.

[theyshapedlikefriends]

Thelodus (aka prehistoric funny fish)

[palaeopedia]

The feeble teeth, Thelodus (1839)

Phylum : Chordata Class : Thelodonti Family : Thelodontidae Genus : Thelodus Species : T. parvidens, T. calvus, T. hoskinsi

Late Silurian

15 cm long (size)

Northern Europe (map)

Although in fish terms Thelodus were very primitive,‭ ‬this genus shows a development towards stronger open water swimming.‭ ‬Thelodus possessed a better developed tail,‭ ‬a dorsal fin‭ (‬on the back‭)‬,‭ ‬and anal fin‭ (‬underside,‭ ‬near the tail‭) ‬as well as rudimentary pectoral fins in the shape of flaps that could be angled‭ ‬to‭ ‬control pitch when swimming.‭ ‬Add to this a mouth that was faced forwards,‭ ‬not down as seen in bottom feeders of the time,‭ ‬and it‭’‬s easy to appreciate that Thelodus were more likely open water fish that either filtered plankton or sucked in small organisms as they swam forward.‭ ‬Additionally,‭ ‬the lack of heavier body commonly seen in other fish genera of the time,‭ ‬further‭ ‬supports an open water,‭ ‬and reliance upon speed instead of armour for defence.