Revision of the leafy liverwort genus Radula (Porellales, Jungermanniopsida) in Baltic and Bitterfeld amber

The phylogenetically isolated leafy liverwort genus Radula comprises ~ 200 extant species and has a near-worldwide distribution. Most species are obligate or facultative epiphytes on tree bark or leaves in humid, tropical or warm-temperate regions. The fossil record of the genus is limited to a few specimens in amber that all deserve re-examination. Based on a revision of Baltic and Bitterfeld amber inclusions from the Geoscientific Museum Göttingen, the Museum für Naturkunde Berlin, and the collection Gröhn we accept three fossil Radula species, R. baltica sp. nov., R. oblongifolia and R. sphaerocarpoides. Radula baltica is known from only a single piece of Baltic amber, whereas the other two species have been reported in Baltic and Bitterfeld amber. A neotype is designated for Radula oblongifolia. Radula oblongifolia and R. sphaerocarpoides are both morphologically variable, yet we are currently unable to discriminate accessions from the different deposits.