Bing Liu, S. Blanco, L. Ector, Zhu-xiang Liu, Juan Ai
Two Surirella species from China are studied using light and scanning electron microscopy. Surirella wulingensis sp. nov., discovered from Li River (located in Wuling Mountains, China), bears five undulations from pole to pole throughout the whole valve diminution series and parallel valve margins, which differ from other similar taxa. Based on the observations of the fine structure, an amended description is provided for S. tientsinensis which possesses a unique character within the genus Surirella: rounded and rimmed outer openings of areolae. Three new morphological terms are proposed: costa-stria bundle (CSB), over-fibula costa (OFC), and mantle sinking against a fibula (MSAF), which can be used for describing some Surirella taxa more succinctly and explicitly including these taxa in this study.
{"title":"Surirella wulingensis sp. nov. and fine structure of S. tientsinensis Skvortzov (Bacillariophyceae) from China","authors":"Bing Liu, S. Blanco, L. Ector, Zhu-xiang Liu, Juan Ai","doi":"10.5507/FOT.2019.006","DOIUrl":"https://doi.org/10.5507/FOT.2019.006","url":null,"abstract":"Two Surirella species from China are studied using light and scanning electron microscopy. Surirella wulingensis sp. nov., discovered from Li River (located in Wuling Mountains, China), bears five undulations from pole to pole throughout the whole valve diminution series and parallel valve margins, which differ from other similar taxa. Based on the observations of the fine structure, an amended description is provided for S. tientsinensis which possesses a unique character within the genus Surirella: rounded and rimmed outer openings of areolae. Three new morphological terms are proposed: costa-stria bundle (CSB), over-fibula costa (OFC), and mantle sinking against a fibula (MSAF), which can be used for describing some Surirella taxa more succinctly and explicitly including these taxa in this study.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46874756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Stancheva, P. Škaloud, M. Pusztai, Chad L. Loflen, R. Sheath
This study presents the first record of the ochrophyte alga Tetrasporopsis fuscescens in North America, confirmed with light and transmission electron microscopic photomicrographs, cytochemical and molecular phylogenetic analyses. T. fuscescens was recorded rarely, being found in the benthos of only twelve stream sites: nine locations in Southern California and three in Northern California. More than half of the streams were non-perennial, characterized by long dry periods. Tetrasporopsis cells were gold-colored, spherical, with a distinct wall, assembled in the periphery of macroscopical gelatinous colonies, which start as tubular or sac-like structures, but later become membranous. The cells have 1-2 parietal chloroplasts, without a stigma or pyrenoid, and reproduction occurs by longitudinal cell division. Other features of the genus are as follows: cells in the colonies also divide by what appears to be smaller autospores with remnant cell walls remaining, the colonial mucilage consists of cylindrical dichotomously branched tubes radiating from the center of the colony to which attach the peripheral cells, and older cells become filled with large oil droplets. A combined gene tree of sequences from nuclear SSU rDNA, plastid rbcL, psaA, psbA and psbC showed that T. fuscescens specimens from Europe and U. S. A. formed a clade, which clustered with taxa classified in the class Chrysomerophyceae.
{"title":"First record of the rare freshwater alga Tetrasporopsis fuscescens (Chrysomerophyceae, Ochrophyta) in North America","authors":"R. Stancheva, P. Škaloud, M. Pusztai, Chad L. Loflen, R. Sheath","doi":"10.5507/FOT.2019.007","DOIUrl":"https://doi.org/10.5507/FOT.2019.007","url":null,"abstract":"This study presents the first record of the ochrophyte alga Tetrasporopsis fuscescens in North America, confirmed with light and transmission electron microscopic photomicrographs, cytochemical and molecular phylogenetic analyses. T. fuscescens was recorded rarely, being found in the benthos of only twelve stream sites: nine locations in Southern California and three in Northern California. More than half of the streams were non-perennial, characterized by long dry periods. Tetrasporopsis cells were gold-colored, spherical, with a distinct wall, assembled in the periphery of macroscopical gelatinous colonies, which start as tubular or sac-like structures, but later become membranous. The cells have 1-2 parietal chloroplasts, without a stigma or pyrenoid, and reproduction occurs by longitudinal cell division. Other features of the genus are as follows: cells in the colonies also divide by what appears to be smaller autospores with remnant cell walls remaining, the colonial mucilage consists of cylindrical dichotomously branched tubes radiating from the center of the colony to which attach the peripheral cells, and older cells become filled with large oil droplets. A combined gene tree of sequences from nuclear SSU rDNA, plastid rbcL, psaA, psbA and psbC showed that T. fuscescens specimens from Europe and U. S. A. formed a clade, which clustered with taxa classified in the class Chrysomerophyceae.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46384775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A novel filamentous, nonheterocytous cyanobacterium was isolated from Lagos Lagoon, Nigeria. The isolate was <3.0 µm wide, untapered, with small rounded polar bodies (aerotopes or cyanophycin granules) visible at the crosswalls, and consequently fit the morphological description of Limnothrix planctonica. Although morphologically inseparable from that species, it was molecularly distant from that taxon, with genetic identities between the two taxa ranging 90.73-92.49%, a degree of separation typical of different genera. Both taxa, as well as Limnothrix rosea, are phylogenetically in the Prochlorotrichaceae, distant from the type species of Limnothrix, L. redekei, which is in the Pseudanabaenaceae. The isolate is herein described as Lagosinema tenuis gen. et sp. nov.
{"title":"Lagosinema tenuis gen. et sp. nov. (Prochlorotrichaceae, Cyanobacteria): a new brackish water genus from Tropical Africa","authors":"S. C. Akagha, J. Johansen, D. Nwankwo, K. Yin","doi":"10.5507/FOT.2018.012","DOIUrl":"https://doi.org/10.5507/FOT.2018.012","url":null,"abstract":"A novel filamentous, nonheterocytous cyanobacterium was isolated from Lagos Lagoon, Nigeria. The isolate was <3.0 µm wide, untapered, with small rounded polar bodies (aerotopes or cyanophycin granules) visible at the crosswalls, and consequently fit the morphological description of Limnothrix planctonica. Although morphologically inseparable from that species, it was molecularly distant from that taxon, with genetic identities between the two taxa ranging 90.73-92.49%, a degree of separation typical of different genera. Both taxa, as well as Limnothrix rosea, are phylogenetically in the Prochlorotrichaceae, distant from the type species of Limnothrix, L. redekei, which is in the Pseudanabaenaceae. The isolate is herein described as Lagosinema tenuis gen. et sp. nov.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47555138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fangfang Cai, Xiaochuang Li, Ruozhen Geng, Xin Peng, Renhui Li
Two cyanobacterial strains morphologically identified to the genus Nostoc were isolated from a wet rocky wall in a mid-subtropical region in China, and they were taxonomically and phylogenetically characterized based on the polyphasic approach combining morphological and genetic characteristics. 16S rRNA gene sequence analysis showed that the two strains containing six clones were all >99.6% similar to each other, but had < 94.3% similarities to the existing cyanobacterial genera. The phylogenies based on 16S rRNA and rpoC1 gene sequences indicated that their sequences grouped into a unique and robust cluster with high bootstrap values. This unique cluster was separated from the clade of the 'Nostoc sensu stricto' and the respective clades formed by the morphologically similar genera Mojavia, Desmonostoc, Aliinostoc, Komarekiella and Halotia. The 16S-23S rRNA ITS secondary structure of the both strains exhibited the unique pattern of D1-D1´, Box-B and V3 helix, distinguishing it from the other heterocytous genera. Such a clear cluster leads to the establishment of Minunostoc gen. nov., with the type species as Minunostoc cylindricum sp. nov.
{"title":"Phylogenetically distant clade of Nostoc-like taxa with the description of Minunostoc gen. nov. and Minunostoc cylindricum sp. nov","authors":"Fangfang Cai, Xiaochuang Li, Ruozhen Geng, Xin Peng, Renhui Li","doi":"10.5507/FOT.2018.013","DOIUrl":"https://doi.org/10.5507/FOT.2018.013","url":null,"abstract":"Two cyanobacterial strains morphologically identified to the genus Nostoc were isolated from a wet rocky wall in a mid-subtropical region in China, and they were taxonomically and phylogenetically characterized based on the polyphasic approach combining morphological and genetic characteristics. 16S rRNA gene sequence analysis showed that the two strains containing six clones were all >99.6% similar to each other, but had < 94.3% similarities to the existing cyanobacterial genera. The phylogenies based on 16S rRNA and rpoC1 gene sequences indicated that their sequences grouped into a unique and robust cluster with high bootstrap values. This unique cluster was separated from the clade of the 'Nostoc sensu stricto' and the respective clades formed by the morphologically similar genera Mojavia, Desmonostoc, Aliinostoc, Komarekiella and Halotia. The 16S-23S rRNA ITS secondary structure of the both strains exhibited the unique pattern of D1-D1´, Box-B and V3 helix, distinguishing it from the other heterocytous genera. Such a clear cluster leads to the establishment of Minunostoc gen. nov., with the type species as Minunostoc cylindricum sp. nov.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41380860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Psammothidium manguinii is a common constituent of the limnoterrestrial diatom flora of the Antarctic Region. The species shows a broad variability in several morphological and morphometrical features such as valve outline, valve width, striation pattern and length/width ratio. Analysis of the type material of Achnanthes manguinii, described by Hustedt in 1952, and A. manguinii var. elliptica, described by Manguin two years later, together with an analysis of a large number of P. manguinii populations from the sub-Antarctic Region (with samples from all major islands in the southern Atlantic, Indian and Pacific Ocean), resulted in a clear morphological revision of the species. Four new species are described, P. acutomanguinii sp. nov., P. antarcticum sp. nov., P. mannensianum sp. nov. and P. hodgsonii Van de Vijver et Verleyen sp. nov., whereas the former variety elliptica is brought to species level: P. ellipticomanguinii nom. et stat. nov. The morphology, ecology and distribution of all species are discussed and a morphological comparison is made.
{"title":"Revision of the Psammothidium manguinii complex (Bacillariophyta) in the sub-Antarctic Region with the description of four new taxa","authors":"B. Vijver","doi":"10.5507/FOT.2019.001","DOIUrl":"https://doi.org/10.5507/FOT.2019.001","url":null,"abstract":"Psammothidium manguinii is a common constituent of the limnoterrestrial diatom flora of the Antarctic Region. The species shows a broad variability in several morphological and morphometrical features such as valve outline, valve width, striation pattern and length/width ratio. Analysis of the type material of Achnanthes manguinii, described by Hustedt in 1952, and A. manguinii var. elliptica, described by Manguin two years later, together with an analysis of a large number of P. manguinii populations from the sub-Antarctic Region (with samples from all major islands in the southern Atlantic, Indian and Pacific Ocean), resulted in a clear morphological revision of the species. Four new species are described, P. acutomanguinii sp. nov., P. antarcticum sp. nov., P. mannensianum sp. nov. and P. hodgsonii Van de Vijver et Verleyen sp. nov., whereas the former variety elliptica is brought to species level: P. ellipticomanguinii nom. et stat. nov. The morphology, ecology and distribution of all species are discussed and a morphological comparison is made.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46725084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We describe three new Achnanthidium species, A. lacustre sp. nov., A. sublanceolatum sp. nov., and A. taipingensis sp. nov., from Taiping Lake, Anhui Province (China) based on light and scanning electron microscopy. A. lacustre sp. nov. belongs to the "A. minutissimum complex" of the genus, based on it having straight external distal raphe fissures and round to elliptical areolae. Both A. sublanceolatum sp. nov., and A. taipingensis sp. nov. belong to the "A. pyrenaicum complex" of the genus, based on them having transpically-elongated areolae and deflected external distal raphe fissures. All three species are sufficiently different from other similar species based on valve outline, shape of the axial and center areas, and striae density. These three new species are all observed in benthic collections from Taiping Lake.
{"title":"Three new freshwater species of the genus Achnanthidium (Bacillariophyta, Achnanthidiaceae) from Taiping Lake, China","authors":"P. Yu, Q. You, J. Kociolek, Quanxi Wang","doi":"10.5507/FOT.2018.015","DOIUrl":"https://doi.org/10.5507/FOT.2018.015","url":null,"abstract":"We describe three new Achnanthidium species, A. lacustre sp. nov., A. sublanceolatum sp. nov., and A. taipingensis sp. nov., from Taiping Lake, Anhui Province (China) based on light and scanning electron microscopy. A. lacustre sp. nov. belongs to the \"A. minutissimum complex\" of the genus, based on it having straight external distal raphe fissures and round to elliptical areolae. Both A. sublanceolatum sp. nov., and A. taipingensis sp. nov. belong to the \"A. pyrenaicum complex\" of the genus, based on them having transpically-elongated areolae and deflected external distal raphe fissures. All three species are sufficiently different from other similar species based on valve outline, shape of the axial and center areas, and striae density. These three new species are all observed in benthic collections from Taiping Lake.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44004041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One green algal specimen from China was identified as Gongrosira fluminensis Fritsch, due to its unique morphology that pseudoparenchymal basal stratum with rounded or polygonal cells grew into dense little-branched upright threads that reached approximately the same height with specific akinete formation and germination and formed strong cushions without calcification. Examination of the ultrastructural characteristics of plasmodesmata and pyrenoid confirmed that Gongrosira fluminensis Fritsch should be excluded from the order Chaetophorales. The phylogenetic evidence based on DNA sequence data from the nucleus (18S rDNA, ITS rDNA) and chloroplast (tufA) sequences clearly revealed that the Gongrosira fluminensis Fritsch should be classified in the Ulvales (Ulvophyceae) as the new combination species of the genus Lithotrichon Darienko et Proschold, instead of the Chaetophorales (Chlorophyceae). More specimens in conjunction with natural morphological investigation and molecular analyses are required to reevaluate the microfilamentous genus Gongrosira Kutzing and reveal hidden diversities among the Ulvophyceae.
{"title":"Taxonomic transfer of Gongrosira fluminensis Fritsch (Chaetophorales, Chlorophyceae) to Lithotrichon Darienko et Pröschold (Ulvales, Ulvophyceae) based on morphological observation and phylogenetic analyses","authors":"Benwen Liu, Qinghua Wang, Shuyin Li, Jiao Fang, Guoxiang Liu, Zhengyu Hu","doi":"10.5507/FOT.2018.014","DOIUrl":"https://doi.org/10.5507/FOT.2018.014","url":null,"abstract":"One green algal specimen from China was identified as Gongrosira fluminensis Fritsch, due to its unique morphology that pseudoparenchymal basal stratum with rounded or polygonal cells grew into dense little-branched upright threads that reached approximately the same height with specific akinete formation and germination and formed strong cushions without calcification. Examination of the ultrastructural characteristics of plasmodesmata and pyrenoid confirmed that Gongrosira fluminensis Fritsch should be excluded from the order Chaetophorales. The phylogenetic evidence based on DNA sequence data from the nucleus (18S rDNA, ITS rDNA) and chloroplast (tufA) sequences clearly revealed that the Gongrosira fluminensis Fritsch should be classified in the Ulvales (Ulvophyceae) as the new combination species of the genus Lithotrichon Darienko et Proschold, instead of the Chaetophorales (Chlorophyceae). More specimens in conjunction with natural morphological investigation and molecular analyses are required to reevaluate the microfilamentous genus Gongrosira Kutzing and reveal hidden diversities among the Ulvophyceae.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47245147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thirteen Planothidium species are illustrated and discussed in a detailed morphological account based on light and scanning electron microscopy analysis of modern and historic materials related to the names Planothidium rostratum (Ostrup) Lange-Bertalot and Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot. Eight species from freshwater environments in Europe, Asia and South America are proposed as new. All taxa here discussed and illustrated belong to the group of species characterized by the presence of a cavum in the rapheless valve. Additional information concerning their distribution and ecology is briefly commented based on a thorough literature revision.
{"title":"On some common and new cavum-bearing Planothidium (Bacillariophyta) species from freshwater","authors":"C. E. Wetzel, B. Vijver, S. Blanco, L. Ector","doi":"10.5507/FOT.2018.016","DOIUrl":"https://doi.org/10.5507/FOT.2018.016","url":null,"abstract":"Thirteen Planothidium species are illustrated and discussed in a detailed morphological account based on light and scanning electron microscopy analysis of modern and historic materials related to the names Planothidium rostratum (Ostrup) Lange-Bertalot and Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot. Eight species from freshwater environments in Europe, Asia and South America are proposed as new. All taxa here discussed and illustrated belong to the group of species characterized by the presence of a cavum in the rapheless valve. Additional information concerning their distribution and ecology is briefly commented based on a thorough literature revision.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45401740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Members of Quadricoccus-like algae are characterized by oval to ellipsoid cells adherent to the bowl-shaped or stretched, empty mother cell walls and are common in phytoplankton of inland waters. To date, the morphologically similar genera Quadricoccus and Lobocystis are accepted for this group and the former had been phylogenetic positioned in Oocystaceae. In this study, seven strains of Quadricoccus-like algae were identified and successfully cultured in the laboratory. Light and electron microscope observations and phylogenetic analysis revealed that the strains represent three different species within a new genus, described here as Quadricoccopsis gen. nov. It differed from genus Quadricoccus by characteristically cell adherent mode that two pairs of daughter cells connected to the mother cell remnant respectively by the pole and median portion and distinguished from Lobocystis by variable 2-4-8 autospores, characteristically cell adherent mode and only found in limnetic water. The three new species, described here as Q. simplex, Q. parva and Q. glomerata, differed in cell size, colony morphology and autospore number. Phylogenetic analysis revealed the genus Quadricoccopsis in Oocystaceae and a close relationship with Oocystidium, which is far away from the phylogenetic position of Quadricoccus in one of the granulated clades. The Quadricoccus-like algae were, therefore, proved to be a paraphyly. Furthermore, apart from Planctonema-like algae, the Oocystaceae characteristic cell wall ultrastructure, which is multi-layered with cellulose fibrils in each layer perpendicular to those of the adjoining layer, is not shown again in genus Quadricoccopsis. Different cell wall substructures may be related to the colony formation mechanism. Whether the ultrastructure criterion is applied to all the Oocystaceae needs to be re-evaluated and, further, the definition of this family should be discussed.
四轴藻类藻类的特点是卵形到椭球状的细胞附着在碗状或拉伸的空母细胞壁上，在内陆水域的浮游植物中很常见。迄今为止，在形态上相似的Quadricoccus属和Lobocystis属被认为是这一类群，前者在系统发育上被定位在卵囊科。本研究鉴定了7株Quadricoccus-like algae，并在实验室成功培养。光镜、电镜观察和系统发育分析表明，这些菌株代表了一个新属中的三个不同种，这里称之为Quadricoccopsis gen. 11 .它与Quadricoccus属的区别在于两对子细胞分别通过极部和中部与母细胞残体连接的典型细胞贴壁模式，与Lobocystis属的区别在于变异的2-4-8常孢子。典型的细胞贴壁模式，只存在于海水中。这三个新种在细胞大小、菌落形态和自孢子数量上均存在差异，分别为单纯性棉球、小棉球和小球棉球。系统发育分析表明，Quadricoccopsis属属于卵囊科，与卵囊门亲缘关系较近，距离Quadricoccus在粒化分支中的系统发育位置较远。因此，这种类四角藻被证明是一种纲藻。此外，除了类似planctonoma的藻类外，卵囊科的细胞壁超微结构是多层的，每层纤维素原纤维与相邻层垂直，在Quadricoccopsis属中没有再次显示。细胞壁亚结构的不同可能与菌落形成机制有关。超微结构标准是否适用于所有卵囊科，需要重新评估，并进一步讨论这个科的定义。
{"title":"Quadricoccopsis gen. nov., a new genus of Quadricoccus-like algae in Oocystaceae from China (Trebouxiophyceae, Chlorophyta)","authors":"Xudong Liu, Huan Zhu, Huiyin Song, Benwen Liu, Qinghua Wang, Guoxiang Liu, Zhengyu Hu","doi":"10.5507/FOT.2018.005","DOIUrl":"https://doi.org/10.5507/FOT.2018.005","url":null,"abstract":"Members of Quadricoccus-like algae are characterized by oval to ellipsoid cells adherent to the bowl-shaped or stretched, empty mother cell walls and are common in phytoplankton of inland waters. To date, the morphologically similar genera Quadricoccus and Lobocystis are accepted for this group and the former had been phylogenetic positioned in Oocystaceae. In this study, seven strains of Quadricoccus-like algae were identified and successfully cultured in the laboratory. Light and electron microscope observations and phylogenetic analysis revealed that the strains represent three different species within a new genus, described here as Quadricoccopsis gen. nov. It differed from genus Quadricoccus by characteristically cell adherent mode that two pairs of daughter cells connected to the mother cell remnant respectively by the pole and median portion and distinguished from Lobocystis by variable 2-4-8 autospores, characteristically cell adherent mode and only found in limnetic water. The three new species, described here as Q. simplex, Q. parva and Q. glomerata, differed in cell size, colony morphology and autospore number. Phylogenetic analysis revealed the genus Quadricoccopsis in Oocystaceae and a close relationship with Oocystidium, which is far away from the phylogenetic position of Quadricoccus in one of the granulated clades. The Quadricoccus-like algae were, therefore, proved to be a paraphyly. Furthermore, apart from Planctonema-like algae, the Oocystaceae characteristic cell wall ultrastructure, which is multi-layered with cellulose fibrils in each layer perpendicular to those of the adjoining layer, is not shown again in genus Quadricoccopsis. Different cell wall substructures may be related to the colony formation mechanism. Whether the ultrastructure criterion is applied to all the Oocystaceae needs to be re-evaluated and, further, the definition of this family should be discussed.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45999937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The infraspecific relationships of the two most variable species, Pediastrum boryanum and P. duplex s.l. identified on the basis of morphological criteria, have been poorly studied so far. The present study focused on 12 original strains isolated from Polish water bodies and 29 strains from the GenBank database, which represent P. boryanum, P. duplex s.l. varieties and other morphologically similar taxa, against the background of 14 other strains of the family Hydrodictyaceae. In order to estimate the level of congruence between the phylogeny and the classical taxonomic system based on morphological criteria, the strains of P. boryanum and P. duplex s.l., and other morphologically similar taxa were subjected to parallel phylogenetic analyses applying Bayesian and Maximum Likelihood methods to combined molecular data (26S rDNA and rbcL cpDNA) and morphological analyses based on light and scanning electron microscopy, and iconographic documentation of almost all strains published elsewhere. The gene topologies revealed many discrepancies in the morphological features used to delimit the analysed taxa. The polyphyly of both P. boryanum and P. duplex s.l. was confirmed. Pseudopediastrum boryanum var. cornutum (formerly P. boryanum var. cornutum) formed a well supported monophyletic clade, whereas other varieties, including var. boryanum, brevicorne and longicorne, proved to be complex taxa. Previous description of Lacunastrum gracillimum (formerly P. duplex var. gracillimum) was well supported. A clade composed mostly of European strains identified as P. duplex var. rugulosum should be regarded as this taxon, whereas clades containing strains exhibiting P. duplex var. rugulosum-like morphology represent new taxa. Taxonomical changes within both P. boryanum and P. duplex s.l. are required on the basis of a higher number of strains and detailed morphometric data.
{"title":"Evolutionary relationships between the varieties of green algae Pediastrum boryanum and P. duplex s.l. (Chlorophyceae, Hydrodictyaceae)","authors":"J. Lenarczyk, M. Saługa","doi":"10.5507/FOT.2018.004","DOIUrl":"https://doi.org/10.5507/FOT.2018.004","url":null,"abstract":"The infraspecific relationships of the two most variable species, Pediastrum boryanum and P. duplex s.l. identified on the basis of morphological criteria, have been poorly studied so far. The present study focused on 12 original strains isolated from Polish water bodies and 29 strains from the GenBank database, which represent P. boryanum, P. duplex s.l. varieties and other morphologically similar taxa, against the background of 14 other strains of the family Hydrodictyaceae. In order to estimate the level of congruence between the phylogeny and the classical taxonomic system based on morphological criteria, the strains of P. boryanum and P. duplex s.l., and other morphologically similar taxa were subjected to parallel phylogenetic analyses applying Bayesian and Maximum Likelihood methods to combined molecular data (26S rDNA and rbcL cpDNA) and morphological analyses based on light and scanning electron microscopy, and iconographic documentation of almost all strains published elsewhere. The gene topologies revealed many discrepancies in the morphological features used to delimit the analysed taxa. The polyphyly of both P. boryanum and P. duplex s.l. was confirmed. Pseudopediastrum boryanum var. cornutum (formerly P. boryanum var. cornutum) formed a well supported monophyletic clade, whereas other varieties, including var. boryanum, brevicorne and longicorne, proved to be complex taxa. Previous description of Lacunastrum gracillimum (formerly P. duplex var. gracillimum) was well supported. A clade composed mostly of European strains identified as P. duplex var. rugulosum should be regarded as this taxon, whereas clades containing strains exhibiting P. duplex var. rugulosum-like morphology represent new taxa. Taxonomical changes within both P. boryanum and P. duplex s.l. are required on the basis of a higher number of strains and detailed morphometric data.","PeriodicalId":55149,"journal":{"name":"Fottea","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44639926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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