Mamontov Y.S., J.Heinrichs, A. Schäfer-Verwimp, M.S. Ignatov & E.E. Perkovsky. Hepatics from Rovno amber (Ukraine), 2. Acrolejeunea ucrainica sp. nov.
Arctoa (2013) 22: 93-96
A fossil of Lejeuneaceae subfam. Ptychantoideae is described based on an inclusion in Late Eocene Rovno amber. The unbranched sterile shoot has obliquely spreading, squarrose, complicate-bilobed leaves with rounded lobes and some dorsal lobe margins curved backwards as well as suberect upper shoot sectors with small leaves possibly serving for vegetative distribution. Based on morphological similarities the fossil is assigned to the extant genus Acrolejeunea, as A. ucrainica Mamontov, Heinrichs et Schaf.-Verw. sp. nov., being the first fossil of this genus and the third liverwort from Rovno amber.