Two new species of Guimaraesiella Eichler, 1949 (Phthiraptera: Ischnocera: Philopteridae) from Tristan da Cunha finches.

We describe Guimaraesiella (Guimaraesiella) inaccessibilis sp. nov. from the Inaccessible Island finch, Nesospiza acunhae Cabanis, 1873 (Passeriformes: Thraupidae), and Guimaraesiella (Guimaraesiella) aedon sp. nov. from the Nightingale Island finch, Nesospiza questi Lowe, 1923. Considering that the conservation status of both host species is "vulnerable", it can be assumed that G. (G.) inaccessibilis and G. (G.) aedon are also vulnerable.