Ricciopsis sandaolingensis sp. nov., a new fossil bryophyte from the Middle Jurassic Xishanyao Formation in the Turpan-Hami Basin, Xinjiang, Northwest China

Abstract

The liverwort family Ricciaceae has a very sparse fossil record in contrast to its large number of living species and its wide distribution. Fossil thalli collected from the Middle Jurassic Xishanyao Formation at the Sandaoling coal mine, Xinjiang, Northwest China are described. Based on detailed comparison of the gross morphology with related fossil and extant species, we assign these thalli to the fossil genus Ricciopsis and establish a new species Ricciopsis sandaolingensis sp. nov. (Ricciaceae). The new fossil species is characterized by its circular-shaped and rosette-forming thallus, dichotomous branching, linear segments, prominent median ridge and entire margins. Ricciopsis sandaolingenesis probably lived on wet or damp soil close to bodies of water, in the shade of ginkgoalean trees in warm and humid climatic conditions. This discovery represents the first fossil record of Marchantiopsida from the Middle Jurassic Xishanyao Formation in the Turpan-Hami Basin, Xinjiang, Northwest China.