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1.
Richard M. McCourt Kenneth G. Karol Susanne Kaplan Robert W. Hoshaw 《Journal of phycology》1995,31(6):989-995
Sequences for the Rubisco large subunit (rbcL) gene were used to test hypotheses about the evolution of chloroplast shape and thallus type in genera of two families of conjugating green algae (Zygnematales): the Mesotaeniaceae (saccoderm desmids, mostly unicellular) and the Zygnemataceae (strictly filamentous). Unicellular (u) and filamentous (f) genera exhibit a series of three similar chloroplast shapes: ribbonlike (e.g. Spirotaenia [u], Spirogyra [f], and Sirogonium [f], laminate (e.g. Mesotaenium [u] and Mougeotia [f]), and twin-stellate (e.g. Cylindrocystis [u] and Zygnema [f]. Two conflicting phylogenetic hypotheses have been proposed: 1) families are polyphyletic constructs drawn from three lineages, each with unicellular and filamentous taxa characterized by a specific chloroplast shape; or 2) unicells form one monophyletic lineage (Mesotaeniaceae) and filaments form another (Zygnemataceae), with some chloroplast shapes independently derived. The rbcL data strongly refute hypothesis 2 (monophyly of the two traditional families) and support hypothesis 1 in part. Parsimony, maximum likelihood, and neighbor-joining analyses of the rbcL data strongly support monophyly of a clade containing taxa with ribbonlike chloroplasts and, to a lesser extent, monophyly of a second clade of the four genera with the other two chloroplast shapes. Two saccoderm genera (Roya, curved laminate chloroplasts; Netrium, cucumber-shaped chloroplasts) are not members of either of these clades, but they are included in a monophyletic Zygnematales . 相似文献
2.
Richard M. McCourt Kenneth G. Karol Micheline Guerlesquin Monique Feist 《American journal of botany》1996,83(1):125-131
Extant genera of Characeae have been assigned to two tribes: Chareae (Chara, Lamprothamnium, Nitellopsis, and Lychnothamnus) and Nitelleae (Nitella and Tolypella), based on morphology of the thallus and reproductive structures. Character analysis of fossil and extant oogonia suggest that Tolypella is polyphyletic, the genus comprising two sections, one in each of the two tribes. Eleven morphological characters and sequence data for the Rubisco large subunit (rbcL) were used to reconstruct the phylogeny of genera, including the two sections of Tolypella. Parsimony analysis of the rbcL data, with all positions and changes weighted equally, strongly supports the monophyly of the Characeae. The two Tolypella sections form a robust monophyletic group basal to the family. Transversion weighting yielded the same tree but with a paraphyletic Tolypella. The rbcL data strongly support monophyly of tribe Chareae but tribe Nitelleae is paraphyletic. Parsimony analysis of morphological data produced one unrooted tree consistent with monophyly of the two tribes; on this tree the Tolypella sections were paraphyletic. Combining morphological with rbcL data did not change the results derived from rbcL sequences alone. The rbcL data support the monophyly of the Characeae and Coleochaete, which together form a monophyletic sister group to embryophytes. 相似文献
3.
We newly sequenced the nuclear-encoded small subunit (SSU) rDNA coding region for 21 taxa of the genus Closterium. The new sequences were integrated into an alignment with 13 known sequences of conjugating green algae representing six traditional families (i.e. Zygnemataceae, Mesotaeniaceae, Gonatozygaceae, Peniaceae, Closteriaceae, and Desmidiaceae) and five known charophycean sequences as outgroups. Both maximum likelihood and maximum parsimony analyses supported with high bootstrap values one large clade containing all placoderm desmids (Desmidiales). All the Closterium taxa formed one clade with 100% bootstrap support, indicating their monophyly, but not paraphyly, as suggested earlier. As to the taxa within the genus Closterium , we found two clades of morphologically closely related taxa in both maximum likelihood and maximum parsimony trees. They corresponded to the C. calosporum species complex and the C. moniliferum-ehrenbergii species complex. It is of particular interest that the homothallic entity of C. moniliferum v. moniliferum was distinguished from and ancestral to all other entities of the C. moniliferum-ehrenbergii species complex. Superimposing all 50 charophycean sequences on the higher order SSU rRNA structure model of Closterium , we investigated degrees of nucleotide conservation at a given position in the nucleotide sequence. A characteristic \"signature\" structure to the genus Closterium was found as an additional helix at the tip of V1 region. In addition, eight base deletions at the tip of helix 10 were found to be characteristic of the C. calosporum species complex, C. gracile , C. incurvum , C. pleurodermatum , and C. pusillum v. maius. These taxa formed one clade with an 82% bootstrap value in maximum parsimony analysis. 相似文献
4.
Christopher S. Drummond John Hall Kenneth G. Karol Charles F. Delwiche Richard M. McCourt 《Journal of phycology》2005,41(5):1055-1064
DNA sequence data were obtained for the gene encoding the large subunit of RUBISCO (rbcL) from 26 strains of Spirogyra and seven of Sirogonium, using as outgroups 10 genera in the Zygnematales and Desmidiales (Closterium, Cosmarium, Cylindrocystis, Gonatozygon, Mesotaenium, Netrium, Penium, Zygnema, Zygnemopsis, Zygogonium). Sequence data were analyzed using maximum parsimony (MP), maximum likelihood (ML), and Bayesian inference (BI), with bootstrap replication (MP, ML) and posterior probabilities (BI) as measures of support. MP, ML, and BI analyses of the rbcL data strongly support a single clade containing Spirogyra and Sirogonium. The Spirogyra taxa are monophyletic, with the exception of Spirogyra maxima (Hassall) Wittrock, which is nested within a clade with Sirogonium and shares with them the characters of loosely spiraled chloroplasts (<1 complete turn per cell) and anisogamy of gametangial cells; S. maxima differs from Sirogonium in displaying well‐defined conjugation tubes rather than a tubeless connection involving bending (genuflection) of filaments. The ML and BI analyses place this Sirogonium/Spirogyra maxima clade sister to the remaining Spirogyra. Morphological differences among strains of Spirogyra grouped together on the basis of rbcL data, including laboratory strains derived from clonal cultures (Spirogyra communis, S. pratensis), indicate that some characters (filament width, chloroplast number) used in the traditional taxonomy of this group are poor measures of species identity. However, some characters such as replicate end walls and loose spiraling of chloroplasts may be synapomorphies for Spirogyra clades. 相似文献
5.
Forty-seven species of desmids, representing all four families, were examined for the presence of the xanthophyll loroxanthin by reverse-phase high-performance liquid chromatography. In the Desmidiaceae 28 of the 35 species examined possessed loroxanthin, and in the Mesotaeniaceae two of the six examined had loroxanthin present. All six species of the families Peniaceae and Closteriaceae examined possessed loroxanthin. Although the distribution of loroxanthin appears to be disjunct in the desmids and does not have strict taxonomic significance, it does follow a coherent pattern consistent with current ideas on desmid phylogeny. This pattern suggests that loroxanthin synthesis probably evolved once in the desmid lineage, with one or more subsequent reversals. 相似文献
6.
Young plants of E. intestinalis have been grown in culture. Cutting off the thalli of attached plants just above the basal rhizoids leads to the regeneration of new branches. After a short time the point of wounding is indistinguishable. The process can be repeated many times; each regeneration resulting in a more branched thallus. Segments of unattached plants kept in culture may give rise to rhizoids from the basal cut ends and to papillae from the upper ends. They may also produce “bottle brush” forms similar to those found amongst ship-fouling algae. Such forms seem to arise when “swarmers” are retained in the parent cell and germinate in situ to give aggregations of juvenile plants. Their formation can be stimulated by a temperature shock. 相似文献
7.
Klebsormidium is a cosmopolitan genus of green algae, widespread in terrestrial and freshwater habitats. The classification of Klebsormidium is entirely based on morphological characters, and very little is understood about its phylogeny at the species level. We investigated the diversity and phylogenetic relationships of Klebsormidium in urban habitats in Europe by a combination of approaches including examination of field‐collected material, culture experiments conducted in many different combinations of factors, and phylogenetic analyses of the rbcL gene. Klebsormidium in European cities mainly occurs at the base of old walls, where it may produce green belts up to several meters in extent. Specimens from different cities showed a great morphological uniformity, consisting of long filaments 6–9 μm in width, with thin‐walled cylindrical cells and smooth wall, devoid of false branches, H‐shaped pieces, and biseriate parts. Conversely, the rbcL phylogeny showed a higher genetic diversity than expected from morphology. The strains were separated in four different clades supported by high bootstrap values and posterior probabilities. In culture, these clades differed in several characters, such as production of a superficial hydro‐repellent layer, tendency to break into short fragments, and inducibility of zoosporulation. On the basis of the taxonomic information available in the literature, most strains could not be identified unambiguously at the species level. The rbcL phylogeny showed no correspondence with classification based on morphology and suggested that the identity of many species, in particular the type species K. flaccidum (kütz.) P.C. Silva, Mattox et W. H. Blackw., needs critical reassessment. 相似文献
8.
9.
Ultrastructural study showed that the sequence of developmental events occurring during spermatozoid maturation in Coleochaete pulvinata Braun was similar in a number of respects to sperm development in the Charales and lower land plants. Elaboration of cytoskeletal components and associated flagellar basal bodies occurs early, and is followed by an extensive decrease in cytoplasmic volume and increases in densities of cytoplasm and nucleoplasm. Volume decrease and density increases appear to result from exocytosis involving dictyosome vesicles and perhaps endoplasmic reticulum. Elongation of flagella is accompanied by deposition of flagellar and body scales as in the Charales. During final stages of sperm maturation, the MLS undergoes changes in organization of the lamellar strip, which may also occur in archegoniates. In mature sperm of C. pulvinata the MLS and basal bodies are so occluded by dense material that determination of absolute orientation (configuration) is difficult. Thus, absolute orientation of the flagellar apparatus was determined by study of mid-stage spermatids, and found to be the same as previously described by Sluiman for zoospores of C. pulvinata. Finally, it is proposed that the large complex, striated fiber which connects basal bodies in C. pulvinata has been evolutionarily reduced in the Charales and Phaeoceros sp., ultimately disappearing from most embryophytic lines of descent. 相似文献
10.
Appreciation of the true species diversity of the genus Ulva in Australian waters has been blinkered by the unproved assumption that its representatives there are largely cosmopolitan. As species of Ulva are some of the longest‐standing and most widely reported taxa of macroalgae, the presumption that they are worldwide in distribution has led to most Australian members being equated with species originally described from extra‐Australian type localities. Ulva species can be notoriously difficult to identify due to the few and often variable characters on which classical taxonomic studies focus so that names of specimens in hand, as well as names appearing in historical distribution records, are frequently difficult or impossible to verify. The combination of morphological and molecular analyses, the latter involving both nuclear (internal transcribed spacer [ITS]) and plastid (rbcL) markers, is critically important in taxonomic studies of the genus and has here been applied to selected Ulva populations from mostly cool‐temperate southern Australian localities. It has been determined that habit‐ and anatomy‐based keys of standard taxonomic literature are largely adequate for assigning species names based on classical concepts, but they often obscure a number of cryptic and pseudocryptic species that do not conform to extra‐Australian populations of the same designation, as indicated by the corresponding molecular data. Here, we present six species (Ulva australis Aresch., U. compressa Forssk., U. fasciata Delile, U. intestinalis L., U. laetevirens Aresch., U. tanneri H. S. Hayden et J. R. Waaland) for which anatomical and molecular data were congruent with both classical concepts and GenBank accession data and confirm these as cosmopolitan taxa in Australia. We also present six putative species designations based on anatomy [U. clathrata (Roth) C. Agardh, U. flexuosa Wulfen, U. linza L., U. prolifera O. F. Müll., U. stenophylla Setch. et N. L. Gardner, U. brisbanensis sp. nov.] that are inconsistent with molecular data, suggesting novel or cryptic taxa not represented in GenBank. 相似文献
11.
Frederick W. Zechman 《Journal of phycology》2003,39(4):819-827
The phylogeny of the green algal Order Dasycladales was inferred by maximum parsimony and Bayesian analyses of chloroplast‐encoded rbcL sequence data. Bayesian analysis suggested that the tribe Acetabularieae is monophyletic but that some genera within the tribe, such as Acetabularia Lamouroux and Polyphysa Lamouroux, are not. Bayesian analysis placed Halicoryne Harvey as the sister group of the Acetabularieae, a result consistent with limited fossil evidence and monophyly of the family Acetabulariaceae but was not supported by significant posterior probability. Bayesian analysis further suggested that the family Dasycladaceae is a paraphyletic assemblage at the base of the Dasycladales radiation, casting doubt on the current family‐level classification. The genus Cymopolia Lamouroux was inferred to be the basal‐most dasycladalean genus, which is also consistent with limited fossil evidence. Unweighted parsimony analyses provided similar results but primarily differed by the sister relationship between Halicoryne Lamouroux and Bornetella Munier‐Chalmas, thus supporting the monophyly of neither the families Acetabulariaceae nor Dasycladaceae. This result, however, was supported by low bootstrap values. Low transition‐to‐transversion ratios, potential loss of phylogenetic signal in third codon positions, and the 550 million year old Dasycladalean lineage suggest that dasyclad rbcL sequences may be saturated due to deep time divergences. Such factors may have contributed to inaccurate reconstruction of phylogeny, particularly with respect to potential inconsistency of parsimony analyses. Regardless, strongly negative g1 values were obtained in analyses including all codon positions, indicating the presence of considerable phylogenetic signal in dasyclad rbcL sequence data. Morphological features relevant to the separation of taxa within the Dasycladales and the possible effects of extinction on phylogeny reconstruction are discussed relative to the inferred phylogenies. 相似文献
12.
13.
Todd R. Disotell 《Evolutionary anthropology》1996,5(1):18-24
The living Old World monkeys, family Cercopithecidae, are the most successful group of nonhuman primates alive today. Overall, they account for over one quarter of the extant genera of primates and approximately 40% of the species. They have an extensive fossil record extending back to the early and middle Miocene of Africa.1,2 Despite this specific diversity and a long evolutionary history, it is commonly argued that the group is relatively uniform in both its skeletal3 and dental4 anatomy, suggesting that much of the current taxonomic diversity is a relatively recent phenomenon. In such a species group, it is perhaps not surprising that the taxonomy of Old World monkeys is subject to many differing classifications. Thus, in recent years, authors have recognized as few as 10 and as many as 22 different genera within the family. Although some of this greater-than-two-fold difference in the number of genera can be attributed to the “splitting” versus “lumping” philosophies of different researchers, much of it is based on major disagreements over phylogenetic relationships. Recent studies of the genetics and chromosomes of this group have illuminated Old World monkey phylogeny in many ways. Some of these studies have resolved longstanding debates based on morphological data; others have revealed phylogenetic relationships that morphologists had never suspected. 相似文献
14.
Olivier De Clerck Frederik Leliaert Heroen Verbruggen Christopher E. Lane Joel Campos De Paula Dioli Ann Payo Eric Coppejans 《Journal of phycology》2006,42(6):1271-1288
Dictyota is a genus of tropical to warm temperate brown algae characterized by parenchymatous, flattened thalli that grow from a single, transversely oriented apical cell. Dictyota is currently distinguished from allied genera of the tribe Dictyoteae (Dilophus, Glossophora, Glossophorella, and Pachydictyon) by the structure of the cortical and medullary layers, as well as the relative abundance of surface proliferations. Even though the traditional classification of the Dictyoteae has repeatedly been criticized in the past, the absence of sound molecular data has so far discouraged any new taxonomic proposals apart from a merger of Dilophus with Dictyota, which has been accepted by only part of the phycological community. Phylogenetic analysis of rbcL gene, partial 26S rDNA sequence, and combined data sets, including four of five generitypes, demonstrates that the traditional classification does not accurately reflect the evolutionary history of the group. None of the genera are resolved as a monophyletic clade. Hence, a merger of Glossophora, Glossophorella, and Pachydictyon in Dictyota is proposed. Two new genera, Canistrocarpus (incorporating D. cervicornis, D. crispata, and D. magneana) and Rugulopteryx (accommodating D. radicans, Dil. suhrii, and Dil. marginata), are proposed. Both genera are supported by molecular indications and a combination of reproductive and vegetative characters. The position of Dil. fastigiatus as a clade sister to Dictyota s.l. and the absence of Dil. gunnianus, the generitype of Dilophus, from the analyses, prevented us from making a more definite statement on the status of the latter genus. 相似文献
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16.
Charles J. O’Kelly Akira Kurihara Tara C. Shipley Alison R. Sherwood 《Journal of phycology》2010,46(4):728-735
Sequences of the nuclear internal transcribed spacer 1 (ITS1) region and the chloroplast rbcL gene were obtained from 86 specimens of Ulva (including “Enteromorpha”) from five of the main Hawaiian Islands. These 86 specimens were divided into 11 operational taxonomic units (OTUs) based on analyses of primary sequence data and comparisons of ITS1 secondary structure. Of the 11 OTUs, six have not previously been reported from anywhere in the world. Only three represented exact sequence matches to named species (Ulva lactuca L., syn. U. fasciata Delile; U. ohnoi Hiraoka et Shimada); two others represented exact sequence matches to unnamed species from Japan and New Zealand. Of the 12 species names currently in use for Hawaiian Ulva, only one, U. lactuca (as U. fasciata), was substantiated. General morphology of the specimens did not always correspond with molecular OTUs; for example, reticulate thallus morphology, previously considered diagnostic for the species U. reticulata Forssk., was expressed in thalli assigned to U. ohnoi and to one of the novel OTUs. This finding confirms a number of recent studies and provides further support for a molecular species concept for Ulva. These results suggest that Ulva populations in tropical and subtropical regions consist of species that are largely unique to these areas, for which the application of names based on types from temperate and boreal European and North American waters is inappropriate. Ulva ohnoi, a “green tide” species, is reported from Hawaii for the first time. 相似文献
17.
Phylogenetic relationships were inferred using nucleotide sequences of the chloroplast gene matK for members of Cornales, a well-supported monophyletic group comprising Cornaceae and close relatives. The shortest trees resulting from this analysis were highly concordant with those based on previous phylogenetic analysis of rbcL sequences. Analysis of a combined matK and rbcL sequence data set (a total of 2652 bp [base pairs]) provided greater resolution of relationships and higher internal support for clades compared to the individual data sets. Four major clades (most inclusive monophyletic groups) of Cornales are indicated by both sets of genes: (1) Cornus-Alangium, (2) nyssoids (Nyssa-Davidia-Camptotheca)- mastixioids (Mastixia, Diplopanax), (3) Curtisia, and (4) Hydrangeaceae-Loasaceae. The combined evidence indicates that clades 2 and 3 are sisters, with clade 4 sister to the remainder of Cornales. These relationships are also supported by other lines of evidence, including synapomorphies in fruit and pollen morphology and gynoecial vasculature. Comparisons of matK and rbcL sequences based on one of the most parsimonious rbcL-matK trees indicate that matK has a much higher A-T content (66.9% in matK vs. 55.8% in rbcL) and a lower transition:transversion ratio (1.23 in matK vs. 2.21 in rbcL). The total number of nucleotide substitutions per site for matK is 2.1 times that of rbcL in Cornales. These findings are similar to recent comparisons of matK and rbcL in other dicots. Variable sites of matK are almost evenly distributed among the three codon positions (1.0:1.0:1.3), whereas variable sites of rbcL are mostly at the third position (1.8:1.0 :7.5). Among- lineages rates of nucleotide substitutions in rbcL are basically homogeneous throughout Cornales, but are more heterogeneous in matK. 相似文献
18.
Harold J. Hoops 《Journal of phycology》1984,20(1):20-27
The somatic cell flagellar apparatuses of Volvox carteri f. weismannia (Powers) Iyengar and V. rousseletii G. S. West have parallel or nearly parallel basal bodies which are separated at their proximal ends. The four microtubular rootlets alternate between two and four members, and all are associated with a striated microtubular associated component (SMAC) that runs between the basal bodies. In addition, each half of the flagellar apparatus apparently rotates during development and loses the 180° rotational symmetry characteristic of most unicellular chlorophycean motile cells. All of these features appear necessary for efficient motion of a colony composed of numerous radially arranged cells. However, the structural details of the flagellar apparatuses of these two species differ. The distance between flagella is greater in V. rousseletii than in V. carteri. One distal striated fiber and two proximal striated fibers connect the basal bodies in V. carteri, but both types of fibers are absent from V. rousseletii. In the latter species, a striated fiber wraps around each of the basal bodies and attaches to the rootlets and the SMAC. No such fiber is present in V. carteri. Since the similarities in the flagellar apparatuses can be explained as a result of adaptation for efficient colonial motion in organisms with similar colonial morphology, the differences suggest a wider phylogenetic distance than previously believed. 相似文献
19.
ENRIQUE MARTÍNEZ‐ANSEMIL MICHEL CREUZÉ DES CHÂTELLIERS PATRICK MARTIN BEATRICE SAMBUGAR 《Zoological Journal of the Linnean Society》2012,166(3):530-558
The Parvidrilidae Erséus, 1999 constitute the most recently described family of oligochaete microdriles. Prior to this study, Parvidrilus strayeri Erséus, 1999, and Parvidrilus spelaeus Martínez‐Ansemil, Sambugar & Giani, 2002, found in groundwaters of the USA (Alabama) and Europe (Slovenia and Italy), respectively, were the only two species in this family. In this paper, six new species – Parvidrilus camachoi , Parvidrilus gianii , Parvidrilus jugeti , Parvidrilus meyssonnieri , Parvidrilus stochi , and Parvidrilus tomasini – and Parvidrilus gineti (Juget, 1959) comb. nov. are added to the family. With all species being stygobiont, the Parvidrilidae is unique in being the only family of oligochaetes worldwide comprising taxa that are restricted to groundwater habitats. Parvidrilids are exceedingly small worms whose principal morphological characteristics are the presence of hair setae in ventral bundles, the markedly posterior position of setae within the segments, the presence of mid‐dorsal glandular pouches in mesosomial segments, the lateral development of the clitellum, the presence of a single male pore in segment XII, and the presence (or absence) of a single spermatheca. The phylogenetic relationships of the Parvidrilidae within the Clitellata were investigated using the nuclear 18S rRNA gene, and the most representative and taxonomically balanced data set of clitellate families available to date. The data were analysed by parsimony, maximum likelihood, and Bayesian inference. Irrespective of the method used, Parvidrilidae were placed far from Capilloventridae, one family once suggested to be closely related to parvidrilids. Although closer to Enchytraeidae than Phreodrilidae, two other suggested putative sister families, the exact position of Parvidrilidae within Clitellata still remained uncertain in the absence of branch support. The examination of reproductive structures, together with the similarity of other important anatomical traits of the new species herein described, reinforced the idea that phreodrilids were the best candidate to be the sister group to parvidrilids on morphological grounds. A fragment of the mitochondrial cytochrome oxidase I gene, used as a barcode, also genetically characterized a few Parvidrilus species. The observation that two species diverge from each other by high genetic distances, even though their type localities are more or less only 100 km apart, is interpreted in the context of low dispersal abilities of inhabitants of the subterranean aquatic ecosystem, and habitat heterogeneity. The Parvidrilidae appear to be a diversified, Holarctic, and probably widely distributed family in groundwater, but very often overlooked because of the small size and external similarity with the polychaete family Aeolosomatidae of its members. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 530–558. 相似文献
20.
The phylogenetic relationship among 12 previously described batrachospermalean taxa and a novel member of the order were investigated using the LSU and rbcL genes separately and in combination. The primary goal of this research was to establish the phylogenetic placement of a previously undescribed freshwater red alga from Chile. The results showed that the new entity with pseudoparenchymatous tube morphology is a member of the Batrachospermales and Petrohua bernabei gen. et sp. nov. is described herein. This is the first record to our knowledge of a Lemanea‐like alga from Chile. It would appear that this thallus construction has evolved at least three times in the Batrachospermales and that the switch from a Batrachospermum‐like construction to a pseudoparenchymatous construction may be a repeated adaptive response to turbulent waterfall habitats. In addition to providing information about a new freshwater red alga, this study sought to determine whether combining the data from two genes would produce a more robust phylogeny, particularly for intermediate nodes, to resolve familial relationships within the order. As with previous analyses, the Batrachospermales was resolved as a clade and support was high for relationships resolved among relatively recent nodes. Unfortunately, combining the LSU and rbcL data did not have the desired effect of more fully resolving intermediate nodes among the Batrachospermales. 相似文献