Promissum is an extinct genus of conodonts, primitive chordates, that lived during the Upper Ordovician period.

It had a primitive backbone and probably looked like a small eel or large worm, lacking any kind of fins except for perhaps a small one on the tail.

It was relatively large for a conodont, reaching about 40 cm (16 inch) in length.

[2] Well-preserved specimens were discovered in the Soom shale of South Africa in 1994.

This article related to an Ordovician animal is a stub.