| Ceratolejeunea(Lejeuneaceae)is mainly distributed in tropical regions.At present,47 species and 1 subspecies have been accepted in the world.Due to the small size and the easy decomposition of ocelli and oil bodies,it is extremely difficult to classify and identify Ceratolejeunea.The classification of many groups in the genus is controversial.So far,no worldwide revision of Ceratolejeunea has been available.With the worsening of the global climate and ecological environment,the global tropical rainforests have also been greatly reduced.The tropical Ceratolejeunea is also facing great challenges.Therefore,the phylogenetic research of Ceratolejeunea was done by combining morphological and molecular phylogenetic analyses.Besides,the evolutionary history and potential distribution areas of Ceratolejeunea were studied by biogeographical methods.One hundred and sixty-two specimens collected from Brazil,Malaysia,Indonesia,Thailand,Singapore,Brunei,etc were morphologically studied.The phylogenetic trees were constructed using the maximum parsimony method,the maximum likelihood method and the Bayesian inference analyses based on the chloroplast genes rbc L,trn L–F and the nuclear genes nr ITS of 97 specimens with typical morphological characters.Max Ent V3.4.1 was used to predict the potential distribution locations of apples in the last glacial maximum,mid-Holocene,modern and future,to understand the influence of climate factors of their distribution and the reasons for their distribution pattern.BEAST V2.6.0 was used to estimate the divergence time and RASP V3.2 was used to explore the ancestral areas of Ceratolejeunea.The main results are the following:1.A new subgenus Acantholejeunea with the type species,C.spinistipula(Herzog)R.L.Zhu et al.,is proposed.Subgenus Ceratolejeunea is supported and subgenus Ceratophora is treated as a new synonym of subgenus Ceratolejeunea;2.Four new species were discovered and described: C.zartmanii sp.nov.from Brazil,C.subminor sp.nov.and C.yongii sp.nov.from Malaysia,C.uniocellata sp.nov.from Brunei;3.Two species names were resurrected: C.caducifolia(Spruce)Steph.and C.oceanica(Mitt.)Steph.;4.Fifty-three species of Ceratolejeunea are recognized in the world.The key to subgenera and species is provided.Colorful plates of some species are provided;5.The isothermy has the greatest influence on the distribution of Ceratolejeunea.Only Taiwan and Hainan are suitable areas in China,while Yunnan is an unsuitable area.Ceratolejeunea sinensis P.C.Chen & P.C.Wu,an endemic species from Yunnan,is an identification error;6.According to the analysis of the suitable habitats of Ceratolejeunea in the modern and future,it is found that the habitat of Ceratolejeunea in the future mainly shows shrinkage trend,with the shrinkage degree of the habitat being 33.0143%;7.Ceratolejeunea likely originated in the middle Eocene(40.1 Ma).The diversification of two subgenera took place between the end of Eocene and the beginning of Oligocene(36.5 Ma),and the species evolutionary rate was the fastest from the end of Miocene to Pleistocene;8.Ceratolejeunea likely originated from tropical Asia,of which subgenus Ceratolejeunea originated from tropical America,and subgenus Acantholejeunea originated from tropical Asia.Through molecular and morphological evidence,a systematic research on worldwide Ceratolejeunea has solved some taxonomic problems.Through the prediction of the potential distribution area,the estimation of divergence time and ancestral areas,the evolutionary history and of Ceratolejeunea can be further understood.These studies can provide theoretical basis for the conservation of species diversity of bryophytes. |
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