First fossil liverwort with in situ flask-shaped receptacles from the Lower Cretaceous of Inner Mongolia, China

We describe a new fossil liverwort assignable to the Blasiaceae from the Lower Cretaceous Huolinhe Formation in the Huolinhe Basin of Inner Mongolia, northeastern China. The new species, Blasiites huolinhensis sp. nov., resembles the extant Blasia in having prominent costae, strap-like segments and flask-shaped receptacles. This is the first report of a fossil liverwort with in situ flask-shaped receptacles. Based on the flask-shaped receptacles and its morphological similarities to the extant genus Blasia, the fossil genus Blasiites is assigned to the extant Blasiaceae (Blasiales, Blasiidae). The divergence time of the Blasiales can date back to the Mississippian (323.2-358.9 Ma, Late Carboniferous) according to fossil records of Blasiites. The occurrence of B. huolinhensis fills a major gap in the fossil record of the Blasiaceae in the Mesozoic, and provides additional evidence for the humid environment in the Huolinhe Basin during the Valanginian-Hauterivian (Early Cretaceous). (C) 2020 Elsevier Ltd. All rights reserved.