The Southern Bristle Tyrant is a small forest flycatcher. A regional account from Misiones, northeastern Argentina, records an adult feeding recently fledged young.
It has a short, pointed black bill with a pinkish base to the lower mandible. The dark gray crown, blackish nape, white brows, yellow ear region, black malar stripes, green back, and yellow belly are described in the museum guide.
The guide lists forests as habitat. At a provincial park in Misiones, an adult was observed carrying food to young that had fledged.
An extinction-risk assessment has not been added yet.