| abstract | Only one quill mite species representing the subfamily Picobiinae Johnston & Kethley, 1973 (Acariformes, Syringophilidae) has been known from gruiform birds (Gruiformes, Rallidae) up to now, i. e., Rafapicobia melzeri Skoracki et al., 2014 recorded from hosts belonging to four genera of rails, Rallus, Pardirallus, Porzana, and Zapornia. Herein we describe the second species, Rafapicobia exilis sp. nov., collected from the Grey-breasted Crake Laterallus exilis (Temminck, 1831) from Brazil. Additionally, the key to the species of Rafapicobia is presented. |