First evidence of Ricciaceae in the Jurassic of the Iberian Peninsula (Asturias, NW Spain): Ricciopsis asturicus sp. nov

ABSTRACT A new species of liverwort, Ricciopsis asturicus sp. nov., is described from dinosaur-bearing Kimmeridgian (Upper Jurassic) deposits of the Lastres Formation in Asturias (NW Spain, Iberian Peninsula) based on a new combination of taxonomic characters, including differences in thallus shape, branching, segment surface, size, and shape. This new species represents the oldest evidence of bryophyte from the Mesozoic of the Iberian Peninsula so far, and it also represents the first evidence of the genus Ricciopsis in this area. In addition to the description of the Ricciaceae remains, palynological analyses were carried out in order to understand the paleoenvironmental context. The remains of Ricciopsis asturicus sp. nov. were found in life position on grey marly siltstones forming dense mats, suggesting that some areas of the Lastres Formation presented shallow freshwater pools placed in channel abandonment areas into an upper deltaic plain, where these mats of liverworts could proliferate during the apparent semiarid climatic conditions occurring during the deposit of the Lastres Formation. This interpretation is supported by the palynological study, which reveals the presence of ferns and Cheirolepidaceae plants (Leptolepidites sp., Klukisporites sp., and tetrads of Classopollis sp.) in nearby areas.