|1st Species||Birkenia elegans|
|2nd Species||Birkenia robusta|
|Time Range||443.7-422.9 mya|
|Location||United Kingdom, Norway, Sweden, Finland, Denmark, Estonia, Canada|
|Physical Dimensions||10 centimeters long|
Birkenia is a birkeniid birkeniiform jawless fish from the Llandovery-Pridoli of the United Kingdom, Norway, Sweden, Finland, Denmark, Estonia, and Canada. It was named in 1899 by Ramsay H. Traquair. It was one of the many jawless fishes to swim in the Silurian seas, as well as one of the most successful.
Birkenia had a build similar to jawless fish; it had a mobile tail, a large, oval-shaped body, eyes positioned on the side of its head, and a toothless mouth. However, it is a bit different from all others, as it has a crown-shaped projection on its back (followed by smaller, spike-like projections running down its tail), its mouth was slightly bigger than those of other jawless fish, and the fleshy part of its fin faced downwards, as opposed to the upwards-facing tails of other jawless fish. Its body would have been covered in scaly skin.
Birkenia was a planktivore, sucking up colonies of plankton drifting through the water. Its small, toothless mouth would have been used to filter plankton from the water.
Not much is known about Birkenia.