A new genus and species, Rebouliothallus huolinhensis sp. nov., and two uncertain species, Ricciopsis sp. and Hepaticites sp., are described. The fossils were collected from the Lower Cretaceous Huolinhe Formation of Huolinhe Basin, northeastern China. The new genus Rebouliothallus was established in the Aytoniaceae family of Marchantiales. Rebouliothallus huolinhensis appears to be quite similar to species of the extant genus Reboulia Raddi. The species is characterized by the relatively large ventral scales. Ventral scales are large, imbricate and arranged in two rows on the ventral surface. Rhizoids are either pegged or smooth. Ricciopsis sp. is characterized by the rosette- forming thallus. Hepaticites sp. shows some similarities to liverworts. Of the forty-nine Early Cretaceous floras of China, only two floras, one from the Huolinhe basin, Inner Mongolia and the other from the Jixi Basin, Heilongjiang Province, contain fossil liverworts. The rare fossil liverwort records in the Early Cretaceous floras of China may be the result of taphonomic bias.
LI RuiyunWANG XuelianJIN PeihongMA FujunYAN DefeiLIN ZhichengSUN Bainian
The present paper reports two new species of Buxus from the Oligocene Ningming Formation of Guangxi, South China, on the basis of several compressed fossil leaves.Buxus ningmingensis sp.nov.is characterized by an elliptic to ovate shape; pinnate venation with marginal secondary, long hairs on the adaxial side of the midvein base; and amphistomatic, anomocytic stomata with a prominent outer ring.All of these characteristics suggest a closest affinity to the living Buxus microphylla subsp.sinica.Another new species identified as Buxus preaustro-yunnanensis sp.nov.is characterized by the diagnostic formation of its admedially branched tertiaries, the trunks of which are often strongly thickened by sclereides.This species is most similar to the extant Buxus austroyunnanensis.The co-occurrence of Buxus ningmingensis sp.nov.and Buxus preaustro-yunnanensis sp.nov.suggests that these two Buxus lived during the Oligocene under a warm, tropical to subtropical climate, similar to the current climate of Ningming.Our findings provide the earliest fossil evidence of Buxus leaves with detailed illustrations of leaf architectural and cuticular features.The occurrence of these two species indicates that Buxus began to diversify in Guangxi no later than the Oligocene.
MA FujunWANG QiujunDONG JunlingYANG YiWANG WenjiaYAN DefeiSUN Bainian
