Preliminary Taxonomic Studies On Dictyosteliaceae In China

The dictyostelids(cellular slime molds) are common components of the animal dung,soil, rot wood and leaf litter micro-organismal complement.They are difficult to be found for their small,transitory presence sorocarps.The main approach of obtaining dictyostelids is collecting samples and isolation in laboratory.The dictyostelids researches especially taxonomy researches were poor in China.So far, thirteen species in two genera in dictyostelids were reported from China.No one studied in this field since 1991.More than 200 samples were obtained from Tibet,Jilin and Liaoning provinces.The isolation procedures described by Cavender and Raper were adopted and improved.Ten new species,two new Chinese records and one new variaty of Dictyostelium,one new species and three new Chinese records of Polysphondylium were obtained during this study. Total 23 species of dictyostelids were obtained during this study.(1) More than 40 samples and 6 species were obtained from Linzhi and Lhasa,Tibet, including D.delicatum,D.sphareocephalum,P.anisocaule,D.multicellularium and D. microsorocarpium.Among them,D.sphareocephalum,P.anisocaule are new records to China, D.sphareocephalum var.evespigium is a new variety,D.multicellularium and D. microsorocarpium are new species.This is the first study of dictyostelids from Tibet.(2) More than 160 samples and 18 species were obtained from Jilin and Liaoning provinces, including P.violaceum,D.minutum,D.giganteum,D.purpurm,D.mucoroides,D.aureo-stipes, P.tikaliensis,P.candium,P.anisocaule,P.symbasimum,D.roridum,D.biserialis,D. cespitosum,D.gregarium,D.membranosum,D.culliculosum,D.confertum and D.parvulum. Among them,D.roridum,D.biserialis,D.cespitosum,D.gregarium,D.membranosum,D. culliculosum,D.confertum,D.parvulum and P.symbasimum are new species,D.aureo-stipes, P.tikaliensis,P.anisocaule and P.candium are new Chinese records.Detailed descriptions and discussions and photographs of the important stages in their life cycles were given to each species;illustrations drawn by hand were given to the new species. Furthermore,keys to the Dictyostelium and Polysphondylium were compiled.Though the prophase studies on dictyostelids were poor,this research could clearly show:dictyostelids are widely distributed in China.This research is not only a supplement for the dictyostelids studies in China,but also discover the new species of dictyostelids in China.And it fills up the blank in this field from 1991,and it establishes firm bases for the further studies in the future.