Pub Date : 2021-09-07DOI: 10.1080/09670262.2021.1948614
U. Tillmann, A. Beran, M. Gottschling, Stephan Wietkamp, M. Hoppenrath
ABSTRACT The Prorocentrales are a unique group of dinophytes based on several apomorphic traits, but species delimitation is challenging within the group. Prorocentrum triestinum was described by Josef Schiller in 1918 as an important bloom-forming species from Trieste (Mediterranean, Adriatic Sea) with a conspicuous asymmetric outline and a small, asymmetrically located subapical spine. All subsequent records under this name fail to conform to Schiller’s original description. These inconsistencies have their origin in John Dodge’s 1975 revision of Prorocentrum, which placed Prorocentrum redfieldii, a more symmetrical, slender species with a long apical spine, into synonymy under P. triestinum. To clarify this confusion, we collected samples at the type locality of P. triestinum in Trieste and established a strain that is morphologically consistent with the protologue and suitable for use in epitypification. Morphology and rRNA sequence data of this strain were compared with four new strains identified as P. redfieldii from the Mediterranean Sea and the North Atlantic Ocean. Cells of P. triestinum had an asymmetric outline in lateral view and a small, dorso-subapical spine. These features, which are readily resolved by light microscopy, were distinct from those of the nearly symmetrical and slender cells of P. redfieldii, which had a long, apically located spine. The species are nevertheless closely related and share an identical architecture of the periflagellar area with a distinctive, largely reduced accessory pore together with a very small platelet 7. This apomorphy clearly differentiates both species from other species of Prorocentrum. Both species differ in their primary rRNA sequences, and ITS and LSU sequence differences will enable them to be distinguished in future meta-barcoding studies. The present study demonstrates that P. triestinum and P. redfieldii are distinct species and thus contributes to a reliable biodiversity assessment of Prorocentrum. HIGHLIGHTS Prorocentrum triestinum is characterised molecularly for the first time and delimited from P. redfieldii. The identity of important bloom-forming species is clarified. Structural details of the periflagellar area are described.
{"title":"Clarifying confusion – Prorocentrum triestinum J.Schiller and Prorocentrum redfieldii Bursa (Prorocentrales, Dinophyceae) are two different species","authors":"U. Tillmann, A. Beran, M. Gottschling, Stephan Wietkamp, M. Hoppenrath","doi":"10.1080/09670262.2021.1948614","DOIUrl":"https://doi.org/10.1080/09670262.2021.1948614","url":null,"abstract":"ABSTRACT The Prorocentrales are a unique group of dinophytes based on several apomorphic traits, but species delimitation is challenging within the group. Prorocentrum triestinum was described by Josef Schiller in 1918 as an important bloom-forming species from Trieste (Mediterranean, Adriatic Sea) with a conspicuous asymmetric outline and a small, asymmetrically located subapical spine. All subsequent records under this name fail to conform to Schiller’s original description. These inconsistencies have their origin in John Dodge’s 1975 revision of Prorocentrum, which placed Prorocentrum redfieldii, a more symmetrical, slender species with a long apical spine, into synonymy under P. triestinum. To clarify this confusion, we collected samples at the type locality of P. triestinum in Trieste and established a strain that is morphologically consistent with the protologue and suitable for use in epitypification. Morphology and rRNA sequence data of this strain were compared with four new strains identified as P. redfieldii from the Mediterranean Sea and the North Atlantic Ocean. Cells of P. triestinum had an asymmetric outline in lateral view and a small, dorso-subapical spine. These features, which are readily resolved by light microscopy, were distinct from those of the nearly symmetrical and slender cells of P. redfieldii, which had a long, apically located spine. The species are nevertheless closely related and share an identical architecture of the periflagellar area with a distinctive, largely reduced accessory pore together with a very small platelet 7. This apomorphy clearly differentiates both species from other species of Prorocentrum. Both species differ in their primary rRNA sequences, and ITS and LSU sequence differences will enable them to be distinguished in future meta-barcoding studies. The present study demonstrates that P. triestinum and P. redfieldii are distinct species and thus contributes to a reliable biodiversity assessment of Prorocentrum. HIGHLIGHTS Prorocentrum triestinum is characterised molecularly for the first time and delimited from P. redfieldii. The identity of important bloom-forming species is clarified. Structural details of the periflagellar area are described.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"207 - 226"},"PeriodicalIF":2.4,"publicationDate":"2021-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43527139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-06DOI: 10.1080/09670262.2021.1959653
H. Kawai, T. Hanyuda, Q. Cheng, K. Miller, A. Peters
ABSTRACT Dictyosiphon asiaticus sp. nov. and D. sparsus sp. nov. are newly described from Japan and the north-western Pacific. Molecular phylogenies based on the mitochondrial cox1 and cox3 and chloroplast atpB, psaA, psbA and rbcL DNA sequences revealed that Dictyosiphon comprises at least seven lineages worldwide. Japanese Dicytosiphon species formed two clades with high support and were sister to a clade including specimens from the cold-water regions of the northern Pacific, the Arctic, and the north-western Atlantic. Specimens of one of the Japanese clades (= D. asiaticus sp. nov.) were morphologically similar to D. foeniculaceus (generitype described from Scotland, UK), having densely branched thalli with fine branches, and were epiphytic on Scytosiphon spp. and Chordaria spp. Specimens of the other Japanese clade (= D. sparsus sp. nov.) were morphologically similar to D. chordaria, having somewhat thicker, sparse branches with blunt tips, and were epiphytic on Chordaria spp. We assign the third clade distributed on both sides of the North Pacific to D. sinicola, which was described from Washington, USA, for the following reasons: Dictyosiphon specimens in the region having relatively densely branched thalli with fine tips have been identified as D. foeniculaceus, and D. sinicola was distinguished from them by its remarkably larger thallus, while anatomically they are very similar. However, D. foeniculaceus is not widely distributed in the region, with only one genetic lineage (species) reported, so that those two taxa are considered to be ecotypes of the same species, and D. sinicola is the valid name for the taxon.
{"title":"Taxonomic revision of Dictyosiphon (Ectocarpales s.l., Phaeophyceae) from the north-western Pacific, with descriptions of D. asiaticus sp. nov. and D. sparsus sp. nov","authors":"H. Kawai, T. Hanyuda, Q. Cheng, K. Miller, A. Peters","doi":"10.1080/09670262.2021.1959653","DOIUrl":"https://doi.org/10.1080/09670262.2021.1959653","url":null,"abstract":"ABSTRACT Dictyosiphon asiaticus sp. nov. and D. sparsus sp. nov. are newly described from Japan and the north-western Pacific. Molecular phylogenies based on the mitochondrial cox1 and cox3 and chloroplast atpB, psaA, psbA and rbcL DNA sequences revealed that Dictyosiphon comprises at least seven lineages worldwide. Japanese Dicytosiphon species formed two clades with high support and were sister to a clade including specimens from the cold-water regions of the northern Pacific, the Arctic, and the north-western Atlantic. Specimens of one of the Japanese clades (= D. asiaticus sp. nov.) were morphologically similar to D. foeniculaceus (generitype described from Scotland, UK), having densely branched thalli with fine branches, and were epiphytic on Scytosiphon spp. and Chordaria spp. Specimens of the other Japanese clade (= D. sparsus sp. nov.) were morphologically similar to D. chordaria, having somewhat thicker, sparse branches with blunt tips, and were epiphytic on Chordaria spp. We assign the third clade distributed on both sides of the North Pacific to D. sinicola, which was described from Washington, USA, for the following reasons: Dictyosiphon specimens in the region having relatively densely branched thalli with fine tips have been identified as D. foeniculaceus, and D. sinicola was distinguished from them by its remarkably larger thallus, while anatomically they are very similar. However, D. foeniculaceus is not widely distributed in the region, with only one genetic lineage (species) reported, so that those two taxa are considered to be ecotypes of the same species, and D. sinicola is the valid name for the taxon.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"251 - 263"},"PeriodicalIF":2.4,"publicationDate":"2021-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49647391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-16DOI: 10.1080/09670262.2021.1923809
Benwen Liu, J. Ge, Huan Zhu, Shuyin Li, Xiaoqi Dong, Guoxiang Liu, Zhengyu Hu
ABSTRACT Chaetophora lobata is the type species of the polyphyletic genus Chaetophora. Clarification of its species identification, phylogenetic relationships, and plastome characteristics is helpful for taxonomic revisions and evolutionary studies of this genus. This study presents detailed information on morphology, culture, phylogenetic analysis, phylogenomics and comparative genomics of C. lobata. The complete morphological description and phylogenetic analyses based on nuclear rDNA and chloroplast protein-coding genes were robust for the identification of C. lobata. Moreover, de novo sequencing was used to determine the 222 213 bp chloroplast genome, which lacked inverted repeats as in all other members of the Chaetophorales. The chloroplast DNA (cpDNA) of C. lobata was found to be AT-rich (68.2%), consisting of 67 protein-coding genes, among which 62 genes were encoded on the plus strand and five genes were encoded on the minus strand with significant imbalance in distribution. Additionally, 28 tRNA genes, three rRNA genes, 16 introns and 18 putative open reading frames (ORFs) were annotated. Eight ORFs arranged in a row occupied about 18 kbp between psaA and atpI genes, and 16 introns (14 group I introns and 2 group II introns) were annotated in nine genes. Six genes contained nine intronic ORFs. Synteny and rearrangements analysis clearly showed the closest relationships between Chaetophora sp. and C. lobata. Substitution rate estimation indicated that the cpDNA of Chaetophorales was under purifying selection and most species were under similar evolutionary pressure. These findings can help advance research on the taxonomy and phylogeny of the order Chaetophorales.
{"title":"Complete chloroplast genome of the green alga Chaetophora lobata (Chlorophyceae, Chlorophyta): morphological features and phylogenetic and comparative analysis","authors":"Benwen Liu, J. Ge, Huan Zhu, Shuyin Li, Xiaoqi Dong, Guoxiang Liu, Zhengyu Hu","doi":"10.1080/09670262.2021.1923809","DOIUrl":"https://doi.org/10.1080/09670262.2021.1923809","url":null,"abstract":"ABSTRACT Chaetophora lobata is the type species of the polyphyletic genus Chaetophora. Clarification of its species identification, phylogenetic relationships, and plastome characteristics is helpful for taxonomic revisions and evolutionary studies of this genus. This study presents detailed information on morphology, culture, phylogenetic analysis, phylogenomics and comparative genomics of C. lobata. The complete morphological description and phylogenetic analyses based on nuclear rDNA and chloroplast protein-coding genes were robust for the identification of C. lobata. Moreover, de novo sequencing was used to determine the 222 213 bp chloroplast genome, which lacked inverted repeats as in all other members of the Chaetophorales. The chloroplast DNA (cpDNA) of C. lobata was found to be AT-rich (68.2%), consisting of 67 protein-coding genes, among which 62 genes were encoded on the plus strand and five genes were encoded on the minus strand with significant imbalance in distribution. Additionally, 28 tRNA genes, three rRNA genes, 16 introns and 18 putative open reading frames (ORFs) were annotated. Eight ORFs arranged in a row occupied about 18 kbp between psaA and atpI genes, and 16 introns (14 group I introns and 2 group II introns) were annotated in nine genes. Six genes contained nine intronic ORFs. Synteny and rearrangements analysis clearly showed the closest relationships between Chaetophora sp. and C. lobata. Substitution rate estimation indicated that the cpDNA of Chaetophorales was under purifying selection and most species were under similar evolutionary pressure. These findings can help advance research on the taxonomy and phylogeny of the order Chaetophorales.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"181 - 192"},"PeriodicalIF":2.4,"publicationDate":"2021-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41926359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-23DOI: 10.1080/09670262.2021.1938240
M. M. Barreto Filho, Pierre M. Durand, Nathan E. Andolfato, A. Jordaan, H. Sarmento, I. L. Bagatini
Abstract Reports of programmed cell death (PCD) across the taxonomic spectrum of photosynthetic unicellular organisms raise questions concerning its ecological and evolutionary roles. However, prior to ecological studies or evolutionary interpretations, it is essential to document phenotypic changes associated with PCD at the single-cell level, since death-related responses vary between taxa and within a single taxon depending on environmental stimuli. Here, we report responses to rapidly changing light, temperature and fluctuations in macronutrients in the model selenastracean green microalga Ankistrodesmus densus (Chlorophyta, Chlorophyceae, Sphaeropleales). We used stringent, but environmentally appropriate, conditions of prolonged darkness, nitrogen starvation (4 days), heat (1 h at 44°C) and cold shock (3 h at 2 ± 2°C). PCD phenotypes were examined by ultrastructural changes, phosphatidylserine (PS) externalization and DNA degradation. Flow cytometric Annexin V FITC analyses revealed that darkness and nitrogen-deprived cultures had significantly higher proportions of cells with PS externalization compared with controls (p < 0.05). Heat and cold treatments did not affect PS externalization (p = 0.44 and p = 0.99, respectively). Transmission electron microscopy (TEM) of light-deprived cells demonstrated, among other ultrastructural changes, marked cytoplasmic vacuolization suggesting a subtype of PCD known as vacuolar cell death. Nitrogen-starved cells had less vacuolization but presented more typical ultrastructural markers of PCD such as chromatin condensation and marginalization. In contrast, the more severe heat and cold shock treatments resulted in necrotic-like features. These findings suggest that prolonged darkness and nitrogen starvation induce PCD in a small (8.4 3.5 and 7.42 2.6%, respectively) but significant (p < 0.05) fraction of the A. densus population. Documenting these different death-related phenotypes depending on different environmental inducers is essential for interpreting ecological studies. Furthermore, our data support the hypothesis that autophagic/vacuolar cell death (VCD), which is central to organism homeostasis in plants (Streptophyta), occurs in Chlorophyta. VCD probably arose long before the evolution of multicellularity in plants. HIGHLIGHTS Darkness and nitrogen deprivation induce different programmed cell death markers in Ankistrodesmus densus; Plant vacuolar-like cell death occurs in Chlorophyta; There is crossover between the vacuolar and apoptosis-like death morphotypes.
关于光合单细胞生物的程序性细胞死亡(PCD)的报道提出了关于其生态和进化作用的问题。然而，在生态学研究或进化解释之前，有必要在单细胞水平上记录与PCD相关的表型变化，因为死亡相关的反应在分类群之间和单个分类群内取决于环境刺激而变化。在这里，我们报道了模型硒纲绿色微藻Ankistrodesmus densus(绿藻，绿藻科，球形藻)对快速变化的光、温度和常量营养素波动的响应。我们使用严格但环境适宜的条件，包括长时间黑暗、氮饥饿(4天)、加热(44°C下1小时)和冷休克(2±2°C下3小时)。通过超微结构变化、磷脂酰丝氨酸(PS)外化和DNA降解检测PCD表型。流式细胞仪Annexin V FITC分析显示，暗培养和无氮培养中PS外化细胞比例显著高于对照组(p < 0.05)。冷热处理对PS外化无显著影响(p = 0.44, p = 0.99)。光剥夺细胞的透射电镜(TEM)显示，在其他超微结构变化中，细胞质空泡化明显，提示PCD的一种亚型，即空泡细胞死亡。氮饥饿细胞空泡化程度较低，但呈现出染色质凝聚和边缘化等典型的PCD超微结构标记。相比之下，更严重的热和冷休克治疗导致坏死样特征。上述结果表明，长时间黑暗和氮饥饿对密度白蚁种群PCD的诱导作用虽小，但显著(p < 0.05)(分别为8.3.4 %和7.42 2.6%)。根据不同的环境诱导剂记录这些不同的死亡相关表型对于解释生态学研究至关重要。此外，我们的数据支持了自噬/液泡细胞死亡(VCD)的假设，这是植物(链藻类)生物稳态的核心，发生在绿藻中。VCD可能早在植物多细胞进化之前就出现了。黑暗和氮剥夺诱导密度按蚊不同的程序性细胞死亡标记;植物液泡样细胞死亡发生在绿藻中;在空泡型和细胞凋亡样死亡形态之间存在交叉。
{"title":"Programmed cell death in the coccoid green microalga Ankistrodesmus densus Korshikov (Sphaeropleales, Selenastraceae)","authors":"M. M. Barreto Filho, Pierre M. Durand, Nathan E. Andolfato, A. Jordaan, H. Sarmento, I. L. Bagatini","doi":"10.1080/09670262.2021.1938240","DOIUrl":"https://doi.org/10.1080/09670262.2021.1938240","url":null,"abstract":"Abstract Reports of programmed cell death (PCD) across the taxonomic spectrum of photosynthetic unicellular organisms raise questions concerning its ecological and evolutionary roles. However, prior to ecological studies or evolutionary interpretations, it is essential to document phenotypic changes associated with PCD at the single-cell level, since death-related responses vary between taxa and within a single taxon depending on environmental stimuli. Here, we report responses to rapidly changing light, temperature and fluctuations in macronutrients in the model selenastracean green microalga Ankistrodesmus densus (Chlorophyta, Chlorophyceae, Sphaeropleales). We used stringent, but environmentally appropriate, conditions of prolonged darkness, nitrogen starvation (4 days), heat (1 h at 44°C) and cold shock (3 h at 2 ± 2°C). PCD phenotypes were examined by ultrastructural changes, phosphatidylserine (PS) externalization and DNA degradation. Flow cytometric Annexin V FITC analyses revealed that darkness and nitrogen-deprived cultures had significantly higher proportions of cells with PS externalization compared with controls (p < 0.05). Heat and cold treatments did not affect PS externalization (p = 0.44 and p = 0.99, respectively). Transmission electron microscopy (TEM) of light-deprived cells demonstrated, among other ultrastructural changes, marked cytoplasmic vacuolization suggesting a subtype of PCD known as vacuolar cell death. Nitrogen-starved cells had less vacuolization but presented more typical ultrastructural markers of PCD such as chromatin condensation and marginalization. In contrast, the more severe heat and cold shock treatments resulted in necrotic-like features. These findings suggest that prolonged darkness and nitrogen starvation induce PCD in a small (8.4 3.5 and 7.42 2.6%, respectively) but significant (p < 0.05) fraction of the A. densus population. Documenting these different death-related phenotypes depending on different environmental inducers is essential for interpreting ecological studies. Furthermore, our data support the hypothesis that autophagic/vacuolar cell death (VCD), which is central to organism homeostasis in plants (Streptophyta), occurs in Chlorophyta. VCD probably arose long before the evolution of multicellularity in plants. HIGHLIGHTS Darkness and nitrogen deprivation induce different programmed cell death markers in Ankistrodesmus densus; Plant vacuolar-like cell death occurs in Chlorophyta; There is crossover between the vacuolar and apoptosis-like death morphotypes.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"193 - 206"},"PeriodicalIF":2.4,"publicationDate":"2021-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09670262.2021.1938240","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44436718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-03DOI: 10.1080/09670262.2020.1814423
A. Prazukin, N. Shadrin, D. Balycheva, Yu. K. Firsov, Raisa Lee, E. Anufriieva
ABSTRACT Cladophora spp. constantly or periodically form floating and benthic mats in Crimean hypersaline lakes and lagoons. In 2017–2018, characteristics of the Cladophora mats and the microalgae on Cladophora filaments were studied employing field research and microscopy. The whole Cladophora mat has a vertical structure, including the upper and lower layers of the floating mat and benthic mat. In total, 50 species of microalgae were found: 40 of them belonged to Bacillariophyta (Bacillariophyceae and Mediophyceae), two to Haptophyta (Coccolithophyceae), four to Miozoa (Dinophyceae), one to Chlorophyta (Zygnematophyceae) and three to Cyanobacteria (Cyanophyceae). Floating layers of the mat differed significantly in species composition from the benthic mat. The total abundance of microalgae and their biomass on Cladophora (per unit area of filaments) varied widely within sampling sites from 3.79 × 106 to 5.04 × 108 cells m–2 and 2.6 to 2197.8 mg m–2. The total mass of microalgae achieved more than 32% of the mass of Cladophora, averaging 7.7% (standard deviation = 13.3).
{"title":"Cladophora spp. (Chlorophyta) modulate environment and create a habitat for microalgae in hypersaline waters","authors":"A. Prazukin, N. Shadrin, D. Balycheva, Yu. K. Firsov, Raisa Lee, E. Anufriieva","doi":"10.1080/09670262.2020.1814423","DOIUrl":"https://doi.org/10.1080/09670262.2020.1814423","url":null,"abstract":"ABSTRACT Cladophora spp. constantly or periodically form floating and benthic mats in Crimean hypersaline lakes and lagoons. In 2017–2018, characteristics of the Cladophora mats and the microalgae on Cladophora filaments were studied employing field research and microscopy. The whole Cladophora mat has a vertical structure, including the upper and lower layers of the floating mat and benthic mat. In total, 50 species of microalgae were found: 40 of them belonged to Bacillariophyta (Bacillariophyceae and Mediophyceae), two to Haptophyta (Coccolithophyceae), four to Miozoa (Dinophyceae), one to Chlorophyta (Zygnematophyceae) and three to Cyanobacteria (Cyanophyceae). Floating layers of the mat differed significantly in species composition from the benthic mat. The total abundance of microalgae and their biomass on Cladophora (per unit area of filaments) varied widely within sampling sites from 3.79 × 106 to 5.04 × 108 cells m–2 and 2.6 to 2197.8 mg m–2. The total mass of microalgae achieved more than 32% of the mass of Cladophora, averaging 7.7% (standard deviation = 13.3).","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"56 1","pages":"231 - 243"},"PeriodicalIF":2.4,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09670262.2020.1814423","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49305171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-28DOI: 10.1080/09670262.2021.1914863
T. Lajeunesse, J. Wiedenmann, P. Casado-Amezúa, I. D’Ambra, Kira E. Turnham, M. R. Nitschke, Clinton A. Oakley, S. Goffredo, C. Spano, V. Cubillos, S. Davy, D. Suggett
ABSTRACT The dinoflagellate family Symbiodiniaceae comprises numerous genera and species with large differences in diversity, ecology and geographic distribution. An evolutionarily divergent lineage common in temperate symbiotic cnidarians and designated in the literature by several informal names including ‘temperate–A’, AI, Phylotype A´ (A-prime) and ‘Mediterranean A’, is here assigned to the genus Philozoon. This genus was proposed by Geddes (1882) in one of the earliest papers that recognized ‘yellow cells’ as distinct biological entities separate from their animal and protist hosts. Using phylogenetic data from nuclear (rDNA), chloroplast (cp23S) and mitochondrial genes (cob and cox1), as well as morphology (cell size), ecological traits (host affinity) and geographic distributions, we emend the genus Philozoon Geddes and two of its species, P. medusarum and P. actiniarum, and describe six new species. Each symbiont species exhibits high host fidelity for particular species of sea anemone, soft coral, stony coral and a rhizostome jellyfish. Philozoon is most closely related to Symbiodinium (formerly Clade A), but, unlike its tropical counterpart, occurs in hosts in shallow temperate marine habitats in northern and southern hemispheres including the Mediterranean Sea, north-eastern Atlantic Ocean, eastern Australia, New Zealand and Chile. The existence of a species-diverse lineage adapted to cnidarian hosts living in high latitude habitats with inherently wide fluctuations in temperature calls further attention to the ecological and biogeographic reach of the Symbiodiniaceae. HIGHLIGHTS A dinoflagellate genus symbiotic with temperate invertebrates is characterized and named using a discarded taxonomic term revived from the golden age of Natural Historians. The work highlights how animal–algal mutualisms are evolved to thrive under a broad range of environmental conditions.
共生鞭毛科(dioflagellate family Symbiodiniaceae)由众多属、种组成，在多样性、生态和地理分布上存在较大差异。在温带共生刺胞动物中常见的进化上不同的谱系，在文献中被指定为几个非正式名称，包括“温带A”，AI, A ' (A-prime)和“地中海A”，这里被分配给Philozoon属。这个属是由Geddes(1882)在最早的一篇论文中提出的，该论文认为“黄细胞”是与动物和原生宿主分离的独特生物实体。利用核(rDNA)、叶绿体(cp23S)和线粒体基因(cob和cox1)的系统发育数据，以及形态(细胞大小)、生态性状(寄主亲和力)和地理分布，对Philozoon Geddes属及其两个种P. medusarum和P. actiniarum进行了修订，并描述了6个新种。每种共生体物种对特定种类的海葵、软珊瑚、石珊瑚和根茎水母都有很高的寄主保真度。Philozoon与symbiodiium(以前的进化门A)关系最密切，但与热带的同类物种不同，它的宿主生活在北半球和南半球的浅温带海洋栖息地，包括地中海、大西洋东北部、澳大利亚东部、新西兰和智利。在高纬度、温度波动较大的生境中，存在一种适应刺胞动物宿主的物种多样性谱系，这进一步引起了人们对共生体科生态和生物地理范围的关注。与温带无脊椎动物共生的鞭毛属被表征并使用从自然历史学家的黄金时代复兴的废弃分类术语命名。这项工作强调了动物-藻类的共生关系是如何在广泛的环境条件下进化而茁壮成长的。
{"title":"Revival of Philozoon Geddes for host-specialized dinoflagellates, ‘zooxanthellae’, in animals from coastal temperate zones of northern and southern hemispheres","authors":"T. Lajeunesse, J. Wiedenmann, P. Casado-Amezúa, I. D’Ambra, Kira E. Turnham, M. R. Nitschke, Clinton A. Oakley, S. Goffredo, C. Spano, V. Cubillos, S. Davy, D. Suggett","doi":"10.1080/09670262.2021.1914863","DOIUrl":"https://doi.org/10.1080/09670262.2021.1914863","url":null,"abstract":"ABSTRACT The dinoflagellate family Symbiodiniaceae comprises numerous genera and species with large differences in diversity, ecology and geographic distribution. An evolutionarily divergent lineage common in temperate symbiotic cnidarians and designated in the literature by several informal names including ‘temperate–A’, AI, Phylotype A´ (A-prime) and ‘Mediterranean A’, is here assigned to the genus Philozoon. This genus was proposed by Geddes (1882) in one of the earliest papers that recognized ‘yellow cells’ as distinct biological entities separate from their animal and protist hosts. Using phylogenetic data from nuclear (rDNA), chloroplast (cp23S) and mitochondrial genes (cob and cox1), as well as morphology (cell size), ecological traits (host affinity) and geographic distributions, we emend the genus Philozoon Geddes and two of its species, P. medusarum and P. actiniarum, and describe six new species. Each symbiont species exhibits high host fidelity for particular species of sea anemone, soft coral, stony coral and a rhizostome jellyfish. Philozoon is most closely related to Symbiodinium (formerly Clade A), but, unlike its tropical counterpart, occurs in hosts in shallow temperate marine habitats in northern and southern hemispheres including the Mediterranean Sea, north-eastern Atlantic Ocean, eastern Australia, New Zealand and Chile. The existence of a species-diverse lineage adapted to cnidarian hosts living in high latitude habitats with inherently wide fluctuations in temperature calls further attention to the ecological and biogeographic reach of the Symbiodiniaceae. HIGHLIGHTS A dinoflagellate genus symbiotic with temperate invertebrates is characterized and named using a discarded taxonomic term revived from the golden age of Natural Historians. The work highlights how animal–algal mutualisms are evolved to thrive under a broad range of environmental conditions.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"166 - 180"},"PeriodicalIF":2.4,"publicationDate":"2021-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09670262.2021.1914863","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45453756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-16DOI: 10.1080/09670262.2021.1888390
Neha Wadmare, A. Baghela, J. Kociolek, B. Karthick
ABSTRACT Stauroneis Ehrenberg is a species-rich genus that is common and widespread with some variation in frustule morphology. Recently, studies have explored the molecular diversity of the Stauroneis from the temperate region, but there are no molecular data for tropical species. In the present study, four species of Stauroneis were investigated using morphological and molecular data. Morphological characters were analysed using light microscopy (LM) and scanning electron microscopy (SEM), and the features of each taxon were compared with similar species within the genus. For the molecular analyses, Stauroneis strains were isolated, cultured, DNA was extracted, and sequences from rbcL and 18S genes were analysed to determine phylogenetic relationships. Our analysis describes three new species and records one previously known species. The new species are: (1) Stauroneis lateritica Wadmare, Kociolek & B.Karthick, characterized by small frustules with elliptical lanceolate valves and short subrostrate apices, broad central bow-tie shaped stauros, and few moderate striae centrally becoming strongly radiate towards the poles; (2) Stauroneis sholaii Wadmare, Kociolek & B.Karthick, which has broad lanceolate valves with short rectangular stauros and radiate striae; and (3) Stauroneis bartii Wadmare, Kociolek & B.Karthick, which has large, lanceolate valves with rounded apices, a stauros with 4–7 shortened striae and radiate striae. Ultrastructure and molecular data from India for the previously known, widespread species Stauroneis gracilis Ehrenberg are presented. The combined morphological and molecular approach supports recognition of S. lateritica, S. sholaii and S. bartii as new species. This study is the first-ever attempt at molecular species discovery of diatoms from the Indian subcontinent.
{"title":"Description and phylogenetic position of three new species of Stauroneis Ehrenberg (Bacillariophyceae: Stauroneidaceae) from the Indian Subcontinent","authors":"Neha Wadmare, A. Baghela, J. Kociolek, B. Karthick","doi":"10.1080/09670262.2021.1888390","DOIUrl":"https://doi.org/10.1080/09670262.2021.1888390","url":null,"abstract":"ABSTRACT Stauroneis Ehrenberg is a species-rich genus that is common and widespread with some variation in frustule morphology. Recently, studies have explored the molecular diversity of the Stauroneis from the temperate region, but there are no molecular data for tropical species. In the present study, four species of Stauroneis were investigated using morphological and molecular data. Morphological characters were analysed using light microscopy (LM) and scanning electron microscopy (SEM), and the features of each taxon were compared with similar species within the genus. For the molecular analyses, Stauroneis strains were isolated, cultured, DNA was extracted, and sequences from rbcL and 18S genes were analysed to determine phylogenetic relationships. Our analysis describes three new species and records one previously known species. The new species are: (1) Stauroneis lateritica Wadmare, Kociolek & B.Karthick, characterized by small frustules with elliptical lanceolate valves and short subrostrate apices, broad central bow-tie shaped stauros, and few moderate striae centrally becoming strongly radiate towards the poles; (2) Stauroneis sholaii Wadmare, Kociolek & B.Karthick, which has broad lanceolate valves with short rectangular stauros and radiate striae; and (3) Stauroneis bartii Wadmare, Kociolek & B.Karthick, which has large, lanceolate valves with rounded apices, a stauros with 4–7 shortened striae and radiate striae. Ultrastructure and molecular data from India for the previously known, widespread species Stauroneis gracilis Ehrenberg are presented. The combined morphological and molecular approach supports recognition of S. lateritica, S. sholaii and S. bartii as new species. This study is the first-ever attempt at molecular species discovery of diatoms from the Indian subcontinent.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"48 - 67"},"PeriodicalIF":2.4,"publicationDate":"2021-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09670262.2021.1888390","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46079488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-16DOI: 10.1080/09670262.2021.1880643
V. Peña, D. Bélanger, P. Gagnon, J. Richards, L. le Gall, Jeffery R. Hughey, G. Saunders, S. Lindstrom, E. Rinde, V. Husa, H. Christie, S. Fredriksen, J. Hall‐Spencer, R. Steneck, Kathryn M. Schoenrock, J. Gitmark, E. S. Grefsrud, M. A. Anglès d’Auriac, E. Legrand, J. Grall, T. Mumford, N. Kamenos, P. Gabrielson
ABSTRACT Coralline red algae in the non-geniculate genera Clathromorphum, Phymatolithon and Lithothamnion are important benthic ecosystem engineers in the photic zone of the Arctic and Subarctic. In these regions, the systematics and biogeography of Clathromorphum and Phymatolithon have mostly been resolved whereas Lithothamnion has not, until now. Seventy-three specific and infraspecific names were given to Arctic and Subarctic Lithothamnion specimens in the late 19th and early 20th century by Frans R. Kjellman and Mikael H. Foslie. DNA sequences from 36 type specimens, five historical specimens, and an extensive sampling of recent collections resulted in the recognition of four Arctic and Subarctic Lithothamnion species, L. glaciale, L. lemoineae, L. soriferum and L. tophiforme. Three genes were sequenced, two plastid-encoded, rbcL and psbA, and the mitochondrial encoded COI-5P; rbcL and COI-5P segregated L. glaciale from L. tophiforme but psbA did not. Partial rbcL sequences obtained from type collections enabled us to correctly apply the earliest available names and to correctly place the remainder in synonymy. We were unable to sequence another 22 type specimens, but all of these are more recent names than those that are now applied. It is difficult to identify these species solely on morpho-anatomy as they can all occur as encrusting corallines or as maerl (rhodoliths). We demonstrate the importance of sequencing historical type specimens by showing that the recently proposed North-east Atlantic L. erinaceum is a synonym of one of the earliest published Arctic species of Lithothamnion, L. soriferum, itself incorrectly placed in synonymy under L. tophiforme based on morpho-anatomy. Based on sequenced specimens, we update the distributions and ecology of these species.
珊瑚红藻属(Clathromorphum、Phymatolithon和Lithothamnion)是北极和亚北极光带重要的底栖生态系统工程师。在这些地区，毛藻门(Clathromorphum)和藻石门(Phymatolithon)的系统学和生物地理学已基本解决，而石石门(Lithothamnion)至今尚未解决。19世纪末和20世纪初，Frans R. Kjellman和Mikael H. Foslie给北极和亚北极石岩鼠标本起了73个特定的和非特定的名字。通过对36个模式标本、5个历史标本和最近收集的大量标本进行DNA序列分析，鉴定出4个北极和亚北极石岩属物种:L. glaciale、L. lemoineae、L. soriferum和L. tophiforme。三个基因测序，两个质体编码，rbcL和psbA，线粒体编码COI-5P;rbcL和COI-5P对L. glaciale和L. tophiforme有分离作用，而psbA没有。从类型集合中获得的部分rbcL序列使我们能够正确地应用最早的可用名称，并将其余部分正确地放置在同义词中。我们无法对另外22个模式标本进行测序，但所有这些都是比现在使用的名称更近的名称。仅从形态解剖学上识别这些物种是困难的，因为它们都可能以嵌壳珊瑚状或珊瑚状(菱形)的形式出现。我们通过展示最近提出的东北大西洋L. erinaceum是最早发表的Lithothamnion的北极物种之一L. soriferum的同义词，证明了历史模式标本测序的重要性，L. soriferum本身基于形态解剖学被错误地置于L. tophiforme的同义词下。根据测序标本，更新了这些物种的分布和生态。
{"title":"Lithothamnion (Hapalidiales, Rhodophyta) in the changing Arctic and Subarctic: DNA sequencing of type and recent specimens provides a systematics foundation*","authors":"V. Peña, D. Bélanger, P. Gagnon, J. Richards, L. le Gall, Jeffery R. Hughey, G. Saunders, S. Lindstrom, E. Rinde, V. Husa, H. Christie, S. Fredriksen, J. Hall‐Spencer, R. Steneck, Kathryn M. Schoenrock, J. Gitmark, E. S. Grefsrud, M. A. Anglès d’Auriac, E. Legrand, J. Grall, T. Mumford, N. Kamenos, P. Gabrielson","doi":"10.1080/09670262.2021.1880643","DOIUrl":"https://doi.org/10.1080/09670262.2021.1880643","url":null,"abstract":"ABSTRACT Coralline red algae in the non-geniculate genera Clathromorphum, Phymatolithon and Lithothamnion are important benthic ecosystem engineers in the photic zone of the Arctic and Subarctic. In these regions, the systematics and biogeography of Clathromorphum and Phymatolithon have mostly been resolved whereas Lithothamnion has not, until now. Seventy-three specific and infraspecific names were given to Arctic and Subarctic Lithothamnion specimens in the late 19th and early 20th century by Frans R. Kjellman and Mikael H. Foslie. DNA sequences from 36 type specimens, five historical specimens, and an extensive sampling of recent collections resulted in the recognition of four Arctic and Subarctic Lithothamnion species, L. glaciale, L. lemoineae, L. soriferum and L. tophiforme. Three genes were sequenced, two plastid-encoded, rbcL and psbA, and the mitochondrial encoded COI-5P; rbcL and COI-5P segregated L. glaciale from L. tophiforme but psbA did not. Partial rbcL sequences obtained from type collections enabled us to correctly apply the earliest available names and to correctly place the remainder in synonymy. We were unable to sequence another 22 type specimens, but all of these are more recent names than those that are now applied. It is difficult to identify these species solely on morpho-anatomy as they can all occur as encrusting corallines or as maerl (rhodoliths). We demonstrate the importance of sequencing historical type specimens by showing that the recently proposed North-east Atlantic L. erinaceum is a synonym of one of the earliest published Arctic species of Lithothamnion, L. soriferum, itself incorrectly placed in synonymy under L. tophiforme based on morpho-anatomy. Based on sequenced specimens, we update the distributions and ecology of these species.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"56 1","pages":"468 - 493"},"PeriodicalIF":2.4,"publicationDate":"2021-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09670262.2021.1880643","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48445350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-08DOI: 10.1080/09670262.2021.1914862
Jeffery R. Hughey, P. Gabrielson, C. Maggs, F. Mineur
ABSTRACT Species of Ulva Linnaeus are nearly impossible to identify using morpho-anatomy due to their simple thallus structure and phenotypic plasticity. The current solution to this problem is to sequence DNA from field-collected specimens and match these sequences to those available in public DNA databases. However, because type specimens of many species have not been sequenced, the accuracy of these identifications is highly doubtful. Ulva rigida C.Agardh is reported to be one of the most widespread and ecologically important Ulva species, but these records are based on either morpho-anatomy or, more recently, on DNA sequences. High-throughput sequencing (HTS) was performed on the lectotype specimen of U. rigida from Cádiz, Spain to determine the correct application of the name. The analysis yielded its complete plastid genome. rbcL, tufA and ITS sequences from the lectotype specimen differed at the species level from all U. rigida sequences deposited in public databases. Instead, the lectotype sequences of U. rigida were identical or very similar to sequences identified as U. rotundata Bliding (referred to by some as U. pseudorotundata Cormaci, G.Furnari & Alongi) from Ireland and Portugal, but not to the holotype of U. rotundata from Italy, which was identical to U. lactuca L. HTS of the lectotype of U. lacinulata (Kützing) Wittrock from Lesina, Croatia, a species morphologically similar to U. rigida with macroscopic marginal teeth, also yielded a complete plastid genome, with sequences identical or highly similar to GenBank U. armoricana Dion, Reviers & Coat, U. ‘laetevirens’, U. ‘rigida’ and U. scandinavica Bliding. Since U. lacinulata is the oldest validly published name, it is the correct one to apply to the globally distributed species that was previously but incorrectly known as U. rigida. Based on this genetic evidence, U. rigida is restricted to European waters and confirmed by DNA sequences from Ireland, Portugal and Spain. This analysis shows that many barcode species identifications and taxonomic conclusions in the genus Ulva are incorrect. Highlights Ulva rigida was misapplied and is restricted to Atlantic Europe. Ulva lacinulata is the dentate species of Ulva distributed worldwide. Ulva rotundata is a heterotypic synonym of U. lactuca.
{"title":"Genomic analysis of the lectotype specimens of European Ulva rigida and Ulva lacinulata (Ulvaceae, Chlorophyta) reveals the ongoing misapplication of names","authors":"Jeffery R. Hughey, P. Gabrielson, C. Maggs, F. Mineur","doi":"10.1080/09670262.2021.1914862","DOIUrl":"https://doi.org/10.1080/09670262.2021.1914862","url":null,"abstract":"ABSTRACT Species of Ulva Linnaeus are nearly impossible to identify using morpho-anatomy due to their simple thallus structure and phenotypic plasticity. The current solution to this problem is to sequence DNA from field-collected specimens and match these sequences to those available in public DNA databases. However, because type specimens of many species have not been sequenced, the accuracy of these identifications is highly doubtful. Ulva rigida C.Agardh is reported to be one of the most widespread and ecologically important Ulva species, but these records are based on either morpho-anatomy or, more recently, on DNA sequences. High-throughput sequencing (HTS) was performed on the lectotype specimen of U. rigida from Cádiz, Spain to determine the correct application of the name. The analysis yielded its complete plastid genome. rbcL, tufA and ITS sequences from the lectotype specimen differed at the species level from all U. rigida sequences deposited in public databases. Instead, the lectotype sequences of U. rigida were identical or very similar to sequences identified as U. rotundata Bliding (referred to by some as U. pseudorotundata Cormaci, G.Furnari & Alongi) from Ireland and Portugal, but not to the holotype of U. rotundata from Italy, which was identical to U. lactuca L. HTS of the lectotype of U. lacinulata (Kützing) Wittrock from Lesina, Croatia, a species morphologically similar to U. rigida with macroscopic marginal teeth, also yielded a complete plastid genome, with sequences identical or highly similar to GenBank U. armoricana Dion, Reviers & Coat, U. ‘laetevirens’, U. ‘rigida’ and U. scandinavica Bliding. Since U. lacinulata is the oldest validly published name, it is the correct one to apply to the globally distributed species that was previously but incorrectly known as U. rigida. Based on this genetic evidence, U. rigida is restricted to European waters and confirmed by DNA sequences from Ireland, Portugal and Spain. This analysis shows that many barcode species identifications and taxonomic conclusions in the genus Ulva are incorrect. Highlights Ulva rigida was misapplied and is restricted to Atlantic Europe. Ulva lacinulata is the dentate species of Ulva distributed worldwide. Ulva rotundata is a heterotypic synonym of U. lactuca.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"143 - 153"},"PeriodicalIF":2.4,"publicationDate":"2021-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09670262.2021.1914862","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48831086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-08DOI: 10.1080/09670262.2021.1892196
M. Pusztai, P. Škaloud
ABSTRACT Until recently, there was no agreement on species delimitation within the morphologically similar chrysophycean genera Uroglena, Uroglenopsis and Urostipulosphaera. In this study, we aimed at a modern taxonomic revision based on the combination of morphological characters (ultrastructure of cysts, cell and colony features) and a multigene phylogeny (SSU, ITS rDNA and rbcL sequences), with ecology taken into account. Of more than 650 explored localities, only approximately one in 10 hosted a viable and detectable population of these colonial chrysophytes at the time of sampling. We established and examined 189 short-term cultures along with single colony isolates, derived mostly from blooming or encysting populations. We obtained the cyst morphology for four species and two lineages of Uroglena, two species of Uroglenopsis, and four species of Urostipulosphaera. A total of 12 resolved lineages could be attributed to previously described species or new species (Uroglena imitata sp. nov., Urostipulosphaera granulata sp. nov.). Based on our molecular analyses and morphological observations, we assign all the previously described Uroglena-like taxa to newly recognized genera and propose a key to identification. Consequently, Uroglena now includes 16 species and two varieties, Uroglenopsis contains four species and Urostipulosphaera encompasses nine species. Within Uroglena and Urostipulosphaera, species are defined by the ultrastructure of their cysts. On the contrary, as Uroglenopsis has simple cysts, species are defined by cell and colony characteristics.
{"title":"Species delimitation within the colonial flagellates Uroglena, Uroglenopsis and Urostipulosphaera (Chrysophyceae)","authors":"M. Pusztai, P. Škaloud","doi":"10.1080/09670262.2021.1892196","DOIUrl":"https://doi.org/10.1080/09670262.2021.1892196","url":null,"abstract":"ABSTRACT Until recently, there was no agreement on species delimitation within the morphologically similar chrysophycean genera Uroglena, Uroglenopsis and Urostipulosphaera. In this study, we aimed at a modern taxonomic revision based on the combination of morphological characters (ultrastructure of cysts, cell and colony features) and a multigene phylogeny (SSU, ITS rDNA and rbcL sequences), with ecology taken into account. Of more than 650 explored localities, only approximately one in 10 hosted a viable and detectable population of these colonial chrysophytes at the time of sampling. We established and examined 189 short-term cultures along with single colony isolates, derived mostly from blooming or encysting populations. We obtained the cyst morphology for four species and two lineages of Uroglena, two species of Uroglenopsis, and four species of Urostipulosphaera. A total of 12 resolved lineages could be attributed to previously described species or new species (Uroglena imitata sp. nov., Urostipulosphaera granulata sp. nov.). Based on our molecular analyses and morphological observations, we assign all the previously described Uroglena-like taxa to newly recognized genera and propose a key to identification. Consequently, Uroglena now includes 16 species and two varieties, Uroglenopsis contains four species and Urostipulosphaera encompasses nine species. Within Uroglena and Urostipulosphaera, species are defined by the ultrastructure of their cysts. On the contrary, as Uroglenopsis has simple cysts, species are defined by cell and colony characteristics.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"57 1","pages":"79 - 95"},"PeriodicalIF":2.4,"publicationDate":"2021-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09670262.2021.1892196","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44389514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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