Phylogeny And Classification Of The Entodon In East Asia Based On Morphological And Molecular Data

The Entodontaceae is one of the largest pleurocarpus families characterized by diverse sporophytic and gametophytic morphologies.Entodon,the core genus of the Entodontaceae,is a large,cosmopolitan genus,with approximately 117 species globally. Traditionally,the genus was divided into two subgenera:Subgenus Entodon,characterized by mostly complanate-foliation,yellow-green to bright green plants with weekly coata, yellowish seta and exannulated capsules and a usually reddish-brown and striolate exostome;and Subgenus Erythropus,recognized by mostly terete-foliation,dark green with strongly costa,reddish seta and annulated capsules,and a usually and yellow-brown to reddish-brown with densely papillose exostome teeth.However,the specimens of Entodon are commonly sterile,and identification is often difficult because gametophyte characteristics for some species in the genus are not easily defined.It is surprising that no fully resolved relationship among species for this genus.This is the first study to improve both classification and phylogeny,on the basis of morphological and molecular characters.East Asia is one of the centers of distribution of Entodon(the other is northern South America),although the Japanese taxa were revised by Mizushima(1960),the Chinese taxa by Hu(1983),about 100 species were reported from the region.However, on the basis of the online database of eastern Asian mosses "An Introduction to the East Asian Moss Database",just 43 species of Entodon have been accepted.Some species have no any further research since they were established e.g.E.armittii C.Muell.,E.buckii Lin.,E.diffusinervis Card.,E.sinense Dix.,E.luteonitens Ren & Card.,E.nepalensis Miz.,E. ovicarpus Dix.,E.seubertianus Fleisch.,E.subplicatus Ren & Card.,E.toba(e|¨)nsis Fleisch.,and E.verrucubsus Wen.Therefore,further phylogenetic analysis,detailed observations of morphological characters and further discussion were strongly needed.In the present study,the genus in East Asia was taxonomically revised,using more than 2000 specimens,which mainly housed at HSNU and NY,some of which were collected by ourselves,and other borrowed from various herbaria all of the world, including 104 samples of type specimens.Among the morphological observations, special attention is paid to peristome structure by means of the scanning electron microscope(SEM).The relationships among members of this genus were discussed.The main conclusions are as follows:(1).Thirty three species of Entodon are recognized as occurring in the region:E. calycinus,E.challengeri,E.chloropus,E.cladorrhizans,E.conchophyllus,E.concinnus,E. curvatirameus,E.divergens,E.diversinervis,E.dolichocucullatus,E.flavescens,E.giraldii,E. kungshanensis,E.longifolius,E.luridus,E.macropodus,E.morrisonensis,E.myurus,E.nepaknsis, E.obtusatus,E.plicatus,E.prorepens,E.pulchellus,E.pylaisioides,E.scabridens,E.scariosus,E. schensianus,E.schleicheri,E.smaragdinus,E.sullivantii,E.taiwanensis,E.viridulus,and E. yunnanensis.(2).Nineteen species of Entodon are newly treated as synonyms of other species: Entodon nanocarpus Müll.Hal.= Entodon challengeri,Entodon zikaiwiensis Paris = Entodon challengeri,Entodon microthecius Broth.= Entodon challengeri,Entodon buckii S.H.Lin = Entodon challengeri,Entodon compressus var.parvisporus X.-S.Wen & Z.-T.Zhao = Entodon challengeri,Entodon verruculosus X.-S.Wen = Entodon cladorrhzans,Entodon excavatus Broth.= Entodon dolichocucullatus,Entodon punctulatus Thér.& P.de la Varde = Entodon giraldii, Entodon diffusinervis Cardot = Entodon luddus,Entodon tereticaulis Nog.= Entodon luridus, Entodon isopterygioides Dixon = Entodon obtusatus,Entodon micropodus Besch.= Entodon prorepens,Entodon myurus var.hokinensis Besch.= Entodon prorepens,Entodon longicostatus W.R. Buck = Entodon prorepens,Entodon aeruginosus Müll.Hal.= Entodon schleicheri,Entodon aeruginosus Müll.Hal.fo.flavescens Müll.Hal.= Entodon schleicheri,Entodon purus Müll.Hal. = Entodon schleicheri,Entodon acutifolius Hu = Platygyriella aurea,and Entodon schensianus var. denticuspis Dixon = Pleurozium schreberi(3).Four species of Entodon are excluded from this genus of this region:Entodon acutifolius Hu transferred to Platygyriella aurea;Entodon schensianus var.denticuspis Dixon transferred to Pleurozium schreberi,Entodon giraldii var.longisetus Müll.Hal.,I am unable to find the original description and original specimens;Entodon seductrix(Hedw.) Mull.Hal., I have been unable find material referred to E.seductrix in the study region. Phylogenetic relationship among the species of Entodon were also investigated.Five genomic regions,two from the nuclear genome(ITS1 and ITS2),and three from the chloroplast genome(trnL intron,trnL-F,and trnG intron).About 500 fresh specimens of this genus in the region were obtained and examined.Nucleotide sequences were determined in 67 species of Entodon and eight outgroup species,the chosen Entodon species represented the majority of those found in East Asia.Phylogenetic trees were constructed by the maximum-paesimony(MP) method,based on individual region and combined regions analysis.The results indicate that(1) the genus Entodon is a monophylous;(2) the genus Entodon could be separated into two subgena,which are identical to the research results of Mizushima(1960) and Buck(1980) on the basis of the morphological characters;(3) Entodon acutifolius is best excluded from the genus Entodon.This is the first significant study of the genus Entodon in East Asia in which both morphological and molecular characters were increased.Through this study,a monograph of Entodon in East Asia is expected to compile,which may provide detailed information for bryophyte research throughout the world.