| The family Longidoridae Thorne,1935 is an important group of cosmopolitan obligate ectoparasites.Longidorids have attracted great attention from scientists all over the world because they can cause damage to a wide range of wild and cultivated plants by directly feeding on root cells and transmitting plant nepoviruses,some virus-transmitting species have been listed as quarantine pests by several countries and regions.In this study,integrative taxonomical approaches using morphological and molecular characterization of 18 S rRNA gene,D2-D3 expension segment of 28 S rRNA,ITS and coxI were carried out for nine species of three Longidorid genera isolated from different habitats in China and Spain.The main results obtained are as follows:1.Xiphinema hangzhouense n.sp.,a new species of Xiphinema in ChinaA new species of Xiphinema was isolated from the rhizosphere of Magnolia grandiflora in Hangzhou,Zhejiang,China.The new species belongs to the Group 1 of Xiphinema proposed by Loof & Luc(1990)and described herein as Xiphinema hangzhouense n.sp.It is characterized by female having a monodelphic reproductive system,no differenciation in uterus,slim body,odontostyle 117.0-128.0 ?m long and vulva located anteriorly at 27.6-31.2% of total body length,tail is elongated conoid with a rounded terminus.Four life stages juveniles were isolated.No males were found.Phylogenetic analyses of D2-D3 expension segment of D2-D3 expension segment of 28 S rRNA,ITS,18 S rRNA and coxI revealed that the new taxon clustered with X.radicicola and X.setariae in a high statistical support.It is also noted that the majority of Group 1 species were reported from Brazil,the USA,Malaysia,France,and India.Only three species,X.brasiliense,X.radicicola and X.hunaniense have been found in China.Discovery of Xiphinema hangzhouense n.sp.indicating that the diversity of group 1 has increased in China.2.A new recorded genus and species,Paralongidorus sali,in China with redescription of Longidorus jonesiPopulations of P.sali and L.jonesi were isolated from the rhizosphere of Cyclobalanopsis glauca in Hangzhou,Zhejiang,China.This is the first record of the occurrence of Paralongidorus in China coupled with a description of the first-stage juvenile and male of L.jonesi.P.sali is characterized by having a dome-shaped lip region,continuous with body contour,SEM observations showed a slit-like oral aperture surrounded by six inner and six outer labial papillaes,labial lobe distinct;amphidial fovea stirrup-shaped,with a conspicuous,crescent-shaped amphidal aperture having slightly rounded margins,odontostyle 112.0-124.5 ?m in length,tail short and hemispherical.No males were found.The juvenile has only three stages.Phylogenetic analysis based on 18 S and D2-D3 expension segment of 28 S rRNA,indicated that P.sali grouped with P.bikanerensis from Iran and L.jonesi clustered with L.jonesi reported from Japan.This study provided the detailed description of both species,and elucidated the difference of lip morphology and amphidial aperture between species of Longidorus,Paralongidorus and Xiphinema.3.New evidence of cryptic species in the family Longidoridae with description of two new speciesA new Longidorus species was isolated from Retama sphaerocarpa L.of Almería Province,and a new Xiphinema species was found from Asphodelus ramosus L.and pasture of Jaén Province of Spain,described herein as L.tabernensis n.sp.and X.subbaetense n.sp.,respectively.The morphological comparision showed that L.tabernensis n.sp.with L.iliturgiensis and L.indalus as cryptic species,and X.subbaetense n.sp.with X.hispanum and X.adenohystherum as cryptic species,strongly resemble the L.iliturgiensis-and X.hispanum-complexes,respectively.Different species delimitation methods(including multivariate and haploweb analyses)were performed to differentiate the cryptic species complexes.Multivariate analysis indicated that the morphometric value range of the majority of specimens are overlapped,and only a few specimens showed values outside of the overall mean values in both cryptic complexes,making it difficult for accurate identification.Inhaploweb analyses,L.tabernensis n.sp.and X.subbaetense n.sp.were clearly separated from L.iliturgiensis-and X.hispanum-complexes.The phylogenetic analyses of D2-D3 expension segment of 28 S rRNA,18 S rRNA and coxI confirmed that the species in above two cryptic complexes are independent and valid species.4.Desciption of two new Longidorus species and two new recorded Xiphinema species in SpainTwo new Longidorus species were isolated from the Pyrenean oaks in Córdoba province,southern Spain and described herein as L.oakcrassus n.sp.and L.oakgracilis n.sp.respectively.The main characteristics of L.oakcrassus n.sp.is having a robust and a very long(9.2-12.2 mm)body;amphidial fovea pocket-shaped,asymmetrically bilobed;odontostyle is 110.0-133.5 ?m long and odontophore weakly developed;tail short and bluntly conoid;male tail region has 23 to 25 mid-ventral supplements.L.oakgracilis n.sp.is characterized by having a thin and medium-sized(5.4-7.9 mm)body;amphidial fovea elongate,funnel-shaped,not lobed;odontostyle relatively long 94.0–106.0 ?m and odontphore typical of this genus;tail short,bluntly hemispherical;male tail region has 12 to 14 mid-ventral supplements.The phylogeny of D2-D3 expension segment of 28 S rRNA,18 S rRNA and coxI showed that these two new species clustered with several species found from the Iberian Peninsula and formed a main clade,while the other main clade is mainly composed of species in other parts of the world,providing insight into the speciation of some of these species specifically to the Iberian Peninsula.Two Xiphinema populations were isolated from the Quercus faginea and Pinus nigra of Jáen province,and identified as X.histriae;another Xiphinema population was isolated from Olea europaea of Huelva province and identified as X.lapidosum.This is the first record of both species in Spain.The present study,provides the molecular characterizations and the description of all juvenile developmental stages for both species.Meanwhile,the morphological comparision of Spanish populations and the paratypes of X.histriae,showed a pseudo-Z-organ with a weakly muscularized wall and containing numerous small dense granular bodies,which was different to the original description by Lamberti et al.(1993).This new findingsuggests that X.histriae must be considered a member of the Group 5 of Xiphinema proposed by Loof & Luc(1990).Phylogenetic analyses of D2-D3 expension segment of 28 S rRNA,ITS1 and coxI indicated that these two species are phylogenetically related to other Xiphinema species reported from Spain.Majority of the old species were described using classical approach,this study provides the morphological and molecular information,new host associations and phylogenetic position among Xiphinema species. |
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