Bohart and Griswold (1997) describe this species from the Death Valley region of southeastern California and adjacent Nevada, USA, and provide illustrations. The genus Protodufourea as a whole is apparently restricted to pollen from the plant family Hydrophyllaceae, with known host plants from the genera Phacelia and Emmenanthe.
Protodufourea koso is 6-7 mm long, and black, with a red abdomen. No information on nesting biology or social behavior is given.
