Hepatics from Rovno amber (Ukraine). 12. Jubula polessica sp. nov.

Abstract

A new fossil leafy liverwort species is described based on its inclusion in Eocene Rovno amber. This species has morphology that is characteristic of extant representatives of the families Frullaniaceae and Jubulaceae, i.e., conduplicate-trilobed leaves with a ventral lobule forming a saccate-clavate watersac with its mouth directed towards the base of the stem, larger dorsal lobes and deeply bifid underleaves. The leaf lobes in the studied plant seem to be dentate near the apex, a character state together with the shape of the underleaves and the underleaf insertion, connects the new species with the Jubulaceae, particularly the extant genera Jubula and Neohattoria, rather than with the Frullaniaceae. The minute size of the fossilized plant, as well as the shape and size of the ventral lobules is reminiscent of Neohattoria, but the more distant lobule position and presence of terminal gynoecia with a single floral series of bracts having entire margins better fit species of Jubula. The fossil is therefore better placed in Jubula, as J. polessica sp. nov., based on its overall morphological similarity with extant members of that genus.