[2] P. phaneronema originates from the Magdalena and Cauca River basins of Colombia.

[3] P. oxyptera inhabits rivers with sandy to muddy bottom.

It forages both during the day and at night, seeking the gill chambers of larger fishes, especially catfishes.

It enters and leaves the gill chamber during the host's ventilating movements.

When gorged with blood, the fish moves to the bottom and buries itself in the sand.