Hepatics from Rovno amber (Ukraine), 6. Frullania rovnoi, sp. nov.

Abstract

A fossil species of the extant liverwort genus Frullania Raddi is described and illustrated, based on a single inclusion in a piece of Rovno amber (Ukraine) that shares its age with Late Eocene Baltic amber, its northern contemporary. Frullania rovnoi is characterised by leaves with a rounded dorsal lobe and the absence of ocelli. The ventral lobe is inflated and forms a saclike lobule, which is bell-shaped and somewhat constricted above the mouth. The bifid underleaves have several blunt teeth or angulations along the shoulder. The Rovno fossil differs sufficiently from morphologically similar species preserved in Baltic and Bitterfeld amber as to be described as new to science. The shape of the lobules and underleaves, as well as the absence of ocelli, indicate an affiliation to F. sect. Australes, hitherto represented in Eocene amber inclusions solely by F. schumannii (Casp.) Grolle. The Rovno fossil is distinguished from extant species of F. subg. Australes and from F. schumannii by having roughly and irregularly dentate-angulate underleaf margins.