Nyssopsora eocaenica Tykhonenko and Hayova sp. nov., the only fossil species of the genus Nyssopsora (Pucciniales), is described from the middle Eocene Sakhalinian amber (Russian Far East). It differs from the other known representatives of the genus by the presence of unbranched hooked appendages on the surface of teliospores. The spores are embedded in the amber sample in close proximity to a syninclusion, Heterotrissocladius naibuchi (Diptera, Chironomidae); most of them are clinged to the insect’s wing or entangled in the bristles on its legs and body. This fossil is ca. 45 myr old and provides useful information for future phylogeny-based calibration and dating of the rust fungi.

Yuri Tykhonenko [yu.ya.tykhonenko@gmail.com; ORCID: https://orcid.org/0000-0001-9000-7406] and Vera Hayova [v.hayova@gmail.com, https://orcid. org/0000-0002-7038-1633] (corresponding author); Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2 Tereshchenkivska Str., Kyiv, 01601, Ukraine. Mikhail Ignatov [misha_ignatov@list.ru; ORCID: https://orcid.org/0000-0001-6096-6315], Tsytsin Main Moscow Botanical Garden of Academy of Sciences, Russian Academy of Sciences, 4 Botanicheskaya Str., Moscow,127276, Russia. Dmitry Vasilenko [damageplant@mail.ru], Borissiak Paleontological Institute, Russian Academy of Sciences, 123 Profsoyuznaya Str, Moscow, 117647, Russia and Cherepovets State University, Lunacharsky Avenue, 5, Cherepovets, 162600, Russia. Evgeny E. Perkovsky [perkovsk@gmail.com; ORCID: https://orcid.org/0000-0002-7959-4379], Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, 15 Bogdan Khmelnitski Str., Kyiv, 01601, Ukraine.