Calkinsia is a genus of alga comprising one species. It lives in low-oxygen seafloor environments. It is not classified in any of the three well-known groups of the Euglenozoa (Kinetoplastida, Euglenida or Diplonemida), but is placed in its own group, the Symbiontida (along with some DNA sequences which were found in marine environments but not identified with known organisms). Some authors have classified Calkinsia alongside Postgaardi

Postgaardi

Postgaardi mariagerensis is a species of single-celled eukaryote in the Euglenozoa. Some have classified it in a class called Postgaardea along with Calkinsia, but as of 2009, Postgaardi is not well enough known to confidently determine its relationship with other organisms in the Euglenozoa...

, but Postgaardi has not been studied well enough to test this hypothesis.