Engelhardia,a genus of Juglandaceae(the walnut family),is endemic to tropical and subtropical Asia.The rich Cenozoic fossil records and distinctive morphological characters of the living plants have been used to explo...Engelhardia,a genus of Juglandaceae(the walnut family),is endemic to tropical and subtropical Asia.The rich Cenozoic fossil records and distinctive morphological characters of the living plants have been used to explore the evolutionary history and geographic distribution of Juglandaceae.However,the taxonomy of this genus has been suffered from a lack of in-depth investigation and good specimens across its distribution ranges.Species delimitation of Engelhardia was defined with seven species in 2020,but detailed information on the circumscription of the species still remains poorly understood.In this study,two new species are described from Sulawesi and Borneo,Engelhardia anminiana and E.borneensis.We also revised and reconstructed the phylogeny within Engelhardia using morphological,molecular(plastid and ribosomal),and distribution data.We sampled 787 individuals in 80 populations,and all the samples were genotyped using plastid regions,trnS-trnG,rps16,trnL-trnF,psbA-trnH,and rpl32-trnL;one ribosomal region,nuclear ribosomal internal transcribed spacer(nrITS).The all datasets were used to reconstruct the phylogenetic relationships.Then,the molecular analyses were combined for 738 sheets of specimens with 15 morphological characteristics to further explore the morphological clusters of Engelhardia.Cluster analysis using morphological data confirmed the delimitation of nine Engelhardia species.Also,phylogenetic analysis based on molecular data(i.e.,plastid and ribosomal)supported the monophyly of Engelhardia and generated phylogenetic trees that included E.fenzelii,E.roxburghiana,E.borneensis,E.hainanensis,E.anminiana,E.serrata,E.villosa,E.apoensis and the varieties of E.spicata(i.e.,E.spicata var.spicata,E.spicata var.rigida,E.spicata var.aceriflora,and E.spicata var.colebrookeana).Our comprehensive taxonomic revision of Engelhardia will provide an insight into understanding the plant diversity in tropical and subtropical Asia.展开更多
We investigated the diversity and structure of free-living marine nematode communities at three sandy beaches representing typical intertidal environments of a temperate zone in Qingdao,Shandong Province,China.Average...We investigated the diversity and structure of free-living marine nematode communities at three sandy beaches representing typical intertidal environments of a temperate zone in Qingdao,Shandong Province,China.Average nematode abundance ranged from 1006 to 2170 ind.10 cm-2,and a total of 34 nematode genera were recorded,of which only 8 were common in all the studied beaches.Pielou's evenness and Shannon-Wiener diversity index were the lowest at the second beach where nematode abundance was the highest.The highest species diversity index coincided with the lowest nematode abundance at Shilaoren beach.Sediment median grain size,sorting coefficient,and chlorophyll-a content were essential for differentiation in nematode abundance and species diversity,whereas taxonomic diversity of nematode was homogeneous across the three beaches.In 0–20 cm sediment profile,nematode abundance declined abruptly with depth,whereas nematode diversity changed gently with obvious difference in 16–20 cm layer.Sediment granulometry and chlorophyll-a content were the two foremost factors which influenced the vertical distribution pattern of nematode generic diversity.Non-selective deposit feeders constituted the most dominant trophic group,followed by epistratum feeders.Bathylaimus(family:Tripyloididae) dominated at the second and Yangkou beach,while Theristus(family:Xyalidae) prevailed at Shilaoren beach.Omnivores and predators became important at Shilaoren beach because of the high proportion of Enoplolaimus.Even though,nematode community of the studied beaches did not differ significantly from each other.展开更多
基金the National Natural Science Foundation of China (No.42171063)Southeast Asia Biodiversity Research Institute,Chinese Academy of Sciences (No. Y4ZK111B01)+1 种基金Youth Innovation Promotion Association,CAS (No. 2018432)the CAS "Light of West China" Program
文摘Engelhardia,a genus of Juglandaceae(the walnut family),is endemic to tropical and subtropical Asia.The rich Cenozoic fossil records and distinctive morphological characters of the living plants have been used to explore the evolutionary history and geographic distribution of Juglandaceae.However,the taxonomy of this genus has been suffered from a lack of in-depth investigation and good specimens across its distribution ranges.Species delimitation of Engelhardia was defined with seven species in 2020,but detailed information on the circumscription of the species still remains poorly understood.In this study,two new species are described from Sulawesi and Borneo,Engelhardia anminiana and E.borneensis.We also revised and reconstructed the phylogeny within Engelhardia using morphological,molecular(plastid and ribosomal),and distribution data.We sampled 787 individuals in 80 populations,and all the samples were genotyped using plastid regions,trnS-trnG,rps16,trnL-trnF,psbA-trnH,and rpl32-trnL;one ribosomal region,nuclear ribosomal internal transcribed spacer(nrITS).The all datasets were used to reconstruct the phylogenetic relationships.Then,the molecular analyses were combined for 738 sheets of specimens with 15 morphological characteristics to further explore the morphological clusters of Engelhardia.Cluster analysis using morphological data confirmed the delimitation of nine Engelhardia species.Also,phylogenetic analysis based on molecular data(i.e.,plastid and ribosomal)supported the monophyly of Engelhardia and generated phylogenetic trees that included E.fenzelii,E.roxburghiana,E.borneensis,E.hainanensis,E.anminiana,E.serrata,E.villosa,E.apoensis and the varieties of E.spicata(i.e.,E.spicata var.spicata,E.spicata var.rigida,E.spicata var.aceriflora,and E.spicata var.colebrookeana).Our comprehensive taxonomic revision of Engelhardia will provide an insight into understanding the plant diversity in tropical and subtropical Asia.
基金supported by the National Natural Science Foundation of China (Nos.40906063,41106122,40730847,and 41576153)
文摘We investigated the diversity and structure of free-living marine nematode communities at three sandy beaches representing typical intertidal environments of a temperate zone in Qingdao,Shandong Province,China.Average nematode abundance ranged from 1006 to 2170 ind.10 cm-2,and a total of 34 nematode genera were recorded,of which only 8 were common in all the studied beaches.Pielou's evenness and Shannon-Wiener diversity index were the lowest at the second beach where nematode abundance was the highest.The highest species diversity index coincided with the lowest nematode abundance at Shilaoren beach.Sediment median grain size,sorting coefficient,and chlorophyll-a content were essential for differentiation in nematode abundance and species diversity,whereas taxonomic diversity of nematode was homogeneous across the three beaches.In 0–20 cm sediment profile,nematode abundance declined abruptly with depth,whereas nematode diversity changed gently with obvious difference in 16–20 cm layer.Sediment granulometry and chlorophyll-a content were the two foremost factors which influenced the vertical distribution pattern of nematode generic diversity.Non-selective deposit feeders constituted the most dominant trophic group,followed by epistratum feeders.Bathylaimus(family:Tripyloididae) dominated at the second and Yangkou beach,while Theristus(family:Xyalidae) prevailed at Shilaoren beach.Omnivores and predators became important at Shilaoren beach because of the high proportion of Enoplolaimus.Even though,nematode community of the studied beaches did not differ significantly from each other.
