This is the second most abundant morphospecies in Pitilla among the Orthocladiinae clade. They are most similar to Orthocladiinae sp. [nigripes] though it differs by having brown posterior parapods instead of black. Though it’s difficult to see the color difference without a microscope, Orthocladiinae sp. [nigripes] usually try to climb in trays or containers and go down rarely, unlike Orthocladiinae sp. [brunnipes] that uses to stay underwater and hug the detritus. They also move differently. When bothered, Orthocladiinae sp. [brunnipes] usually swims with C-movements, mostly staying in the same place; while Orthocladiinae sp. [nigripes] swims with more serpent-like movements and moves forward more efficiently.

We identified one species with molecular species delimitation – five individuals were sequenced.