No abstract

Rice and its relatives are a focal point in agricultural and evolutionary science, but a paucity of fossils has obscured their deep-time history. Previously described cuticles with silica bodies (phytoliths) from the Late Cretaceous period (67-65 ma) of India indicate that, by the latest Cretaceous, the grass family (Poaceae) consisted of members of the modern subclades PACmAD (Panicoideae-Aristidoideae-Chloridoideae-micrairoideae-ArundinoideaeDanthonioideae) and BEP (Bambusoideae-Ehrhartoideae-Pooideae), including a taxon with proposed affinities to Ehrhartoideae. Here we describe additional fossils and show that, based on phylogenetic analyses that combine molecular genetic data and epidermal and phytolith features across Poaceae, these can be assigned to the rice tribe, oryzeae, of grass subfamily Ehrhartoideae. The new oryzeae fossils suggest substantial diversification within Ehrhartoideae by the Late Cretaceous, pushing back the time of origin of Poaceae as a whole. These results, therefore, necessitate a re-evaluation of current models for grass evolution and palaeobiogeography.

Species of the genus Phylloporus in China were investigated based on morphology and molecular phylogenetic analysis of a three-locus (nrLSU, ITS and tef-1a) DNA sequence dataset. Twenty-one phylogenetic species were recognized among the studied collections. Seven of them are described as new: P. brunneiceps, P. imbricatus, P. maculatus, P. pachycystidiatus, P. rubeolus, P. rubrosquamosus, and P. yunnanensis. In addition, four of them correspond with the previous morphology-based taxa: P. bellus, P. luxiensis, P. parvisporus, and P. rufescens. The remaining ten phylogenetic species were not described due to the paucity of the materials. A key to the Chinese morphologically recognizable taxa was provided. A preliminary biogeographical analysis showed that (1) Pylloporus species in East Asia and Southeast Asia are mostly closely related, (2) species pairs or closely related species of Phylloporus between East Asia and North/Central America are relatively common, and (3) the biogeographic relationship of Phylloporus between East Asia and Europe was supported by only a single species pair. Unexpectedly, no taxa common either to both Europe and East Asia, or to both East Asia and North/Central America, were uncovered. Clades look to have taxa from both sides of the Pacific and Europe/Asia though.