Abstract
Examination of two pieces of amber from the mid-Cretaceous of Myanmar revealed seven inclusions of leafy liverworts that we assign to the extinct Frullania cretacea Hentschel et al. 2009. These inclusions show a suite of characters that were not visible in the type specimen of F. cretacea.
The new gametophytes consistently display rectangular to ovate underleaves that have two long-ciliate apical teeth in addition to 0-2 blunt lateral teeth. A narrow stylus is present on at least some leaves.
The lobules usually form water sacs that are 1.2-2.3 times longer than wide, and are arranged at some distance from the stem. The observed combination of character states is not present in extant crown group lineages of Frullania.
A syninclusion in one of the amber pieces is interpreted as a detached gynoecium of a second Cretaceous Frullania species and is described as F. baerlocheri, sp. nov. The subgynoecial underleaves of the syninclusion are suborbicular in shape, and allow for a separation of this species from F. cretacea.
The described amber inclusions are the oldest representatives of an extant genus of leafy liverworts known so far.