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Kenneth G. Karol - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic congruence of ribosomal operon and plastid gene sequences for the Characeae with an emphasis on Tolypella (Characeae, Charophyceae)
Phycologia, 2017Co-Authors: William Pérez, Richard M. Mccourt, Michele T. Casanova, John D. Hall, Kenneth G. KarolAbstract:Abstract: To clarify species diversity of Tolypella (Characeae, Charophyceae) and the relationship between Tolypella and other genera in Characeae, sequence data from the nuclear ribosomal operon were assembled for 18 individuals of Tolypella. These represented nine named species and two potentially new species from Australia, as well as 13 other taxa of Characeae. Phylogenetic analyses were performed on ribosomal gene sequences (18S, 5.8S and 28S) for Characeae and on ribosomal gene and internal transcribed spacer (ITS) sequences (ribosomal genes + ITS1 + ITS2) for Tolypella. Analyses were also performed on the ribosomal gene and ITS sequences combined with plastid gene sequences (atpB, psbC and rbcL). Ribosomal gene sequences alone were conservative and their phylogenetic analyses resulted in topologies similar to a previously published plastid gene-based study but with less support and resolution. In contrast, ITS sequences showed greater variability and their addition resulted in greater resolution am...
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Phylogeny of North American Tolypella (Charophyceae, Charophyta) based on plastid DNA sequences with a description of Tolypella ramosissima sp. nov.
Journal of phycology, 2014Co-Authors: William Pérez, Richard M. Mccourt, John D. Hall, Kenneth G. KarolAbstract:Characeae (Charophyceae, Charophyta) contains two tribes with six genera: tribe Chareae with four genera and tribe Nitelleae, which includes Tolypella and Nitella. This paper uses molecular and morphological data to elucidate the phylogeny of Tolypella species in North America. In the most comprehensive taxonomic treatment of Characeae, 16 Tolypella species worldwide were subsumed into two species, T. intricata and T. nidifica, in two sections, Rothia and Tolypella respectively. It was further suggested that Tolypella might be a derived group within Nitella. In this investigation into species diversity and relationships in North American Tolypella, sequence data from the plastid genes atpB, psbC, and rbcL were assembled for a broad range of charophycean and land plant taxa. Molecular data were used in conjunction with morphology to test monophyly of the genus and species within it. Phylogenetic analyses of the sequence data showed that Characeae is monophyletic but that Nitelleae is paraphyletic with Tolypella sister to a monophyletic Nitella + Chareae. The results also supported the monophyly of Tolypella and the sections Rothia and Tolypella. Morphologically defined species were supported as clades with little or no DNA sequence differences. In addition, molecular data revealed several lineages and a new species (T. ramosissima sp. nov.), which suggests greater species diversity in Tolypella than previously recognized.
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occurrence of matk in a trnk group ii intron in charophyte green algae and phylogeny of the Characeae
American Journal of Botany, 2003Co-Authors: Erin R Sanders, Kenneth G. Karol, Richard M. MccourtAbstract:A group II intron containing the matK gene, which encodes a splicing-associated maturase, was found in the trnK (lysine tRNA) exon in the chloroplast genome of the six extant genera of green algae in the family Characeae, which among green algae are the sister group to embryophytes (land plants). The characean trnK intron (;2.5 kilobases [kb]) and matK ORF (;1.5 kb) are comparable in size to the intron and ORF of land plants, in which they are similarly found inserted in the trnK exon. Domain X, a sequence of conserved amino acid residues within matK, occurs in the Characeae. Phylogenetic analysis using maximum likelihood (GTR 1 I 1 gamma likelihood model) and parsimony (branch and bound search) yielded one tree with high bootstrap support for all branches. The matK tree was congruent with the rbcL tree for the same taxa. The number and proportion of informative sites was higher in matK (501, 31% of matK sequence) compared to rbcL (122, 10%). Characeae branch lengths were on average more than five times longer for matK compared to rbcL and provided better resolution within the Characeae. These findings along with recent genomic analyses demonstrate that the intron and matK invaded the chloroplast genome of green algae prior to the evolution of land plants.
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Phylogeny of extant genera in the family Characeae (Charales, Charophyceae) based on rbcL, sequences and morphology
American Journal of Botany, 1996Co-Authors: Richard M. Mccourt, Micheline Guerlesquin, Kenneth G. Karol, Monique FeistAbstract: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 reprod4ctive 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 paraphyletjc. 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 sequenc9s alone. The rbcL data support the monophyly of the Characeae and Coleochaete, which together form a monophyletic sister group to embryophytes.
Richard M. Mccourt - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic congruence of ribosomal operon and plastid gene sequences for the Characeae with an emphasis on Tolypella (Characeae, Charophyceae)
Phycologia, 2017Co-Authors: William Pérez, Richard M. Mccourt, Michele T. Casanova, John D. Hall, Kenneth G. KarolAbstract:Abstract: To clarify species diversity of Tolypella (Characeae, Charophyceae) and the relationship between Tolypella and other genera in Characeae, sequence data from the nuclear ribosomal operon were assembled for 18 individuals of Tolypella. These represented nine named species and two potentially new species from Australia, as well as 13 other taxa of Characeae. Phylogenetic analyses were performed on ribosomal gene sequences (18S, 5.8S and 28S) for Characeae and on ribosomal gene and internal transcribed spacer (ITS) sequences (ribosomal genes + ITS1 + ITS2) for Tolypella. Analyses were also performed on the ribosomal gene and ITS sequences combined with plastid gene sequences (atpB, psbC and rbcL). Ribosomal gene sequences alone were conservative and their phylogenetic analyses resulted in topologies similar to a previously published plastid gene-based study but with less support and resolution. In contrast, ITS sequences showed greater variability and their addition resulted in greater resolution am...
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Phylogeny of North American Tolypella (Charophyceae, Charophyta) based on plastid DNA sequences with a description of Tolypella ramosissima sp. nov.
Journal of phycology, 2014Co-Authors: William Pérez, Richard M. Mccourt, John D. Hall, Kenneth G. KarolAbstract:Characeae (Charophyceae, Charophyta) contains two tribes with six genera: tribe Chareae with four genera and tribe Nitelleae, which includes Tolypella and Nitella. This paper uses molecular and morphological data to elucidate the phylogeny of Tolypella species in North America. In the most comprehensive taxonomic treatment of Characeae, 16 Tolypella species worldwide were subsumed into two species, T. intricata and T. nidifica, in two sections, Rothia and Tolypella respectively. It was further suggested that Tolypella might be a derived group within Nitella. In this investigation into species diversity and relationships in North American Tolypella, sequence data from the plastid genes atpB, psbC, and rbcL were assembled for a broad range of charophycean and land plant taxa. Molecular data were used in conjunction with morphology to test monophyly of the genus and species within it. Phylogenetic analyses of the sequence data showed that Characeae is monophyletic but that Nitelleae is paraphyletic with Tolypella sister to a monophyletic Nitella + Chareae. The results also supported the monophyly of Tolypella and the sections Rothia and Tolypella. Morphologically defined species were supported as clades with little or no DNA sequence differences. In addition, molecular data revealed several lineages and a new species (T. ramosissima sp. nov.), which suggests greater species diversity in Tolypella than previously recognized.
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occurrence of matk in a trnk group ii intron in charophyte green algae and phylogeny of the Characeae
American Journal of Botany, 2003Co-Authors: Erin R Sanders, Kenneth G. Karol, Richard M. MccourtAbstract:A group II intron containing the matK gene, which encodes a splicing-associated maturase, was found in the trnK (lysine tRNA) exon in the chloroplast genome of the six extant genera of green algae in the family Characeae, which among green algae are the sister group to embryophytes (land plants). The characean trnK intron (;2.5 kilobases [kb]) and matK ORF (;1.5 kb) are comparable in size to the intron and ORF of land plants, in which they are similarly found inserted in the trnK exon. Domain X, a sequence of conserved amino acid residues within matK, occurs in the Characeae. Phylogenetic analysis using maximum likelihood (GTR 1 I 1 gamma likelihood model) and parsimony (branch and bound search) yielded one tree with high bootstrap support for all branches. The matK tree was congruent with the rbcL tree for the same taxa. The number and proportion of informative sites was higher in matK (501, 31% of matK sequence) compared to rbcL (122, 10%). Characeae branch lengths were on average more than five times longer for matK compared to rbcL and provided better resolution within the Characeae. These findings along with recent genomic analyses demonstrate that the intron and matK invaded the chloroplast genome of green algae prior to the evolution of land plants.
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Phylogeny of extant genera in the family Characeae (Charales, Charophyceae) based on rbcL, sequences and morphology
American Journal of Botany, 1996Co-Authors: Richard M. Mccourt, Micheline Guerlesquin, Kenneth G. Karol, Monique FeistAbstract: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 reprod4ctive 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 paraphyletjc. 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 sequenc9s alone. The rbcL data support the monophyly of the Characeae and Coleochaete, which together form a monophyletic sister group to embryophytes.
William Pérez - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic congruence of ribosomal operon and plastid gene sequences for the Characeae with an emphasis on Tolypella (Characeae, Charophyceae)
Phycologia, 2017Co-Authors: William Pérez, Richard M. Mccourt, Michele T. Casanova, John D. Hall, Kenneth G. KarolAbstract:Abstract: To clarify species diversity of Tolypella (Characeae, Charophyceae) and the relationship between Tolypella and other genera in Characeae, sequence data from the nuclear ribosomal operon were assembled for 18 individuals of Tolypella. These represented nine named species and two potentially new species from Australia, as well as 13 other taxa of Characeae. Phylogenetic analyses were performed on ribosomal gene sequences (18S, 5.8S and 28S) for Characeae and on ribosomal gene and internal transcribed spacer (ITS) sequences (ribosomal genes + ITS1 + ITS2) for Tolypella. Analyses were also performed on the ribosomal gene and ITS sequences combined with plastid gene sequences (atpB, psbC and rbcL). Ribosomal gene sequences alone were conservative and their phylogenetic analyses resulted in topologies similar to a previously published plastid gene-based study but with less support and resolution. In contrast, ITS sequences showed greater variability and their addition resulted in greater resolution am...
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Phylogeny of North American Tolypella (Charophyceae, Charophyta) based on plastid DNA sequences with a description of Tolypella ramosissima sp. nov.
Journal of phycology, 2014Co-Authors: William Pérez, Richard M. Mccourt, John D. Hall, Kenneth G. KarolAbstract:Characeae (Charophyceae, Charophyta) contains two tribes with six genera: tribe Chareae with four genera and tribe Nitelleae, which includes Tolypella and Nitella. This paper uses molecular and morphological data to elucidate the phylogeny of Tolypella species in North America. In the most comprehensive taxonomic treatment of Characeae, 16 Tolypella species worldwide were subsumed into two species, T. intricata and T. nidifica, in two sections, Rothia and Tolypella respectively. It was further suggested that Tolypella might be a derived group within Nitella. In this investigation into species diversity and relationships in North American Tolypella, sequence data from the plastid genes atpB, psbC, and rbcL were assembled for a broad range of charophycean and land plant taxa. Molecular data were used in conjunction with morphology to test monophyly of the genus and species within it. Phylogenetic analyses of the sequence data showed that Characeae is monophyletic but that Nitelleae is paraphyletic with Tolypella sister to a monophyletic Nitella + Chareae. The results also supported the monophyly of Tolypella and the sections Rothia and Tolypella. Morphologically defined species were supported as clades with little or no DNA sequence differences. In addition, molecular data revealed several lineages and a new species (T. ramosissima sp. nov.), which suggests greater species diversity in Tolypella than previously recognized.
Mary J Beilby - One of the best experts on this subject based on the ideXlab platform.
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multi scale characean experimental system from electrophysiology of membrane transporters to cell to cell connectivity cytoplasmic streaming and auxin metabolism
Frontiers in Plant Science, 2016Co-Authors: Mary J BeilbyAbstract:The morphology of characean algae could be mistaken for a higher plant: stem-like axes with leaf-like branchlets anchored in the soil by root-like rhizoids. However, all of these structures are made up of giant multinucleate cells separated by multicellular nodal complexes. The excised internodal cells survive long enough for the nodes to give rise to new thallus. The size of the internodes and their thick cytoplasmic layer minimize impalement injury and allow specific micro-electrode placement. The cell structure can be manipulated by centrifugation, perfusion of cell contents or creation of cytoplasmic droplets, allowing access to both vacuolar and cytoplasmic compartments and both sides of the cell membranes. Thousands of electrical measurements on intact or altered cells and cytoplasmic droplets laid down basis to modern plant electrophysiology. Furthermore, the giant internodal cells and whole thalli facilitate research into many other plant properties. As nutrients have to be transported from rhizoids to growing parts of the thallus and hormonal signals need to pass from cell to cell, Characeae possess very fast cytoplasmic streaming. The mechanism was resolved in the characean model. Plasmodesmata between the internodal cells and nodal complexes facilitate transport of ions, nutrients and photosynthates across the nodes. The internal structure was found to be similar to those of higher plants. Recent experiments suggest a strong circadian influence on metabolic pathways producing indole-3-acetic acid (IAA) and serotonin/melatonin. The review will discuss the impact of the characean models arising from fragments of cells, single cells, cell-to-cell transport or whole thalli on understanding of plant evolution and physiology.
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Systems Biology Analysis of Changes in Potential Across Plasma Membrane: Physiological Implications
Rhythms in Plants, 2015Co-Authors: Mary J Beilby, Christina E. Turi, Susan J. MurchAbstract:Variation of the membrane potential difference (PD) across plasma membrane is considered in terms of one or more ion transporter populations changing their conductance and activation kinetics. Slow changes occurring over minutes can be investigated by the current voltage (I/V) technique. In some cases, data are sufficient to model electrical characteristics of each transporter population and their evolution with time. The proton pump at the plasma membrane of the salt-sensitive Characeae Chara australis provides an example of single transporter changing conductance against a steady background. The rise and fall in proton pump conductance may be prompted by circadian oscillations of indoleamines IAA and melatonin, measured in growing thalli of characean plants. In response to abiotic stress, two or more transporter populations change conductance and/or PD dependence. The voltage clamp to extreme negative PD levels transiently inhibits the proton pump in C. australis, activating H+/OH− channels, increasing the background conductance, and opening inward rectifier channels at more depolarized PDs. An increase in medium salinity (after pre-treatment with isotonic sorbitol medium) results in similar response, which is preceded by a typical noise in membrane PD. In salt-tolerant Characeae Lamprothamnium sp., increase in salinity (or osmolarity) provokes an increase in proton pumping as well as increase in background conductance and opening of the inward rectifier channels at more depolarized PDs to effect turgor regulation. The hypoosmotic turgor regulation also involves a complex interaction of several transporters, initiated by the increase of turgor pressure , [Ca2+]cyt increase, and PD changes. A detailed modeling is in progress for most of these responses. The examples demonstrate the analytical and predictive power of the I/V methodology coupled with the systems biology modeling and monitoring of biochemical changes.
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Salt tolerance at single cell level in giant-celled Characeae.
Frontiers in Plant Science, 2015Co-Authors: Mary J BeilbyAbstract:Characean plants provide an excellent experimental system for electrophysiology and physiology due to: (i) very large cell size, (ii) position on phylogenetic tree near the origin of land plants and (iii) continuous spectrum from very salt sensitive to very salt tolerant species. A range of experimental techniques is described, some unique to characean plants. Application of these methods provided electrical characteristics of membrane transporters, which dominate the membrane conductance under different outside conditions. With this considerable background knowledge the electrophysiology of salt sensitive and salt tolerant genera can be compared under salt and/or osmotic stress. Both salt tolerant and salt sensitive Characeae show a rise in membrane conductance and simultaneous increase in Na+ influx upon exposure to saline medium. Salt tolerant Chara longifolia and Lamprothamnium sp. exhibit proton pump stimulation upon both turgor decrease and salinity increase, allowing the membrane PD to remain negative. The turgor is regulated through the inward K+ rectifier and 2H+/Cl- symporter. Lamprothamnium plants can survive in hypersaline media up to twice seawater strength and withstand large sudden changes in salinity. Salt-sensitive Chara australis succumbs to 50 - 100 mM NaCl in few days. Cells exhibit no pump stimulation upon turgor decrease and at best transient pump stimulation upon salinity increase. Turgor is not regulated. The membrane PD exhibits characteristic noise upon exposure to salinity. Depolarization of membrane PD to excitation threshold sets off trains of action potentials, leading to further loses of K+ and Cl-. In final stages of salt damage the H+/OH- channels are thought to become the dominant transporter, dissipating the proton gradient and bringing the cell PD close to 0. The differences in transporter electrophysiology and their synergy under osmotic and/or saline stress in salt sensitive and salt tolerant characean cells are discussed in d
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The Whole Plant and Cell-to-Cell Transport
The Physiology of Characean Cells, 2013Co-Authors: Mary J Beilby, Michelle T CasanovaAbstract:In this chapter, I venture into the less familiar areas of research into cytoplasmic streaming, cell-to-cell transport, gravitropism, cell walls and the role of Characeae in phytoremediation. In all these topics, the methodology unique to Characeae, as well as the wealth of data obtained from single cell measurements, has led to important advances in our knowledge of plants in general. The site for the motive force for streaming cytoplasm was identified using cytoplasm-enriched cell fragments. The actin cables were later observed and connection with myosin established. Characean cells have the myosin that generates very fast sliding. The perfusion technique measured the amount of ATP/Mg2+ needed to provide the energy necessary for the streaming process. The temperature, pH and cytoplasmic calcium concentration dependencies were all investigated, explaining the “freezing” of streaming at the time of an action potential. Interestingly, characean myosin was found to produce sliding in dephosphorylated state only.
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Detached Cells in Steady State: Electrophysiology and Transport
The Physiology of Characean Cells, 2013Co-Authors: Mary J Beilby, Michelle T CasanovaAbstract:This chapter summarises the research on characean detached cells in a steady state. While living cells are continuously developing and ageing, electrophysiological and flux measurements are often performed on the scale of hours where the system can be approximated to be in a stationary state. The measurement and control of potential difference (PD) across the plasma and tonoplast membranes have proved to be very useful tools in understanding cell electrophysiology, especially when coupled with monitoring electrical currents and ion fluxes. Computer control and data logging of these experiments ensured speed, accuracy and complexity, which opened up new avenues of investigation. The size of Characeaen cells allowed detailed measurement of many substances in cell compartments, as well as the manipulation of the compartments themselves. Some of the methodology particular to Characeae is summarised in “Methods Boxes”. Current–voltage (I/V) measurements of the plasma membrane have revealed the most conductive transporters: proton pump, large conductance K+ channels, H+/OH– channels, rectifying and non-selective channels that constitute the background state. Depending on the external (and sometimes internal) conditions, the electrical circuit that represents the membrane can “rewire” itself. The cells can be found in the “pump state”, “K+ state”, “H+/OH− state” or “background state”, the latter underlying all the other states. The manipulation of external conditions and use of channel blockers and metabolic inhibitors has resolved the I/V characteristics of these major transporters and allowed detailed modelling: HGSS model for the pump, and the classical Goldman–Hodgkin–Katz model, supplemented by Boltzmann distribution of open probabilities, for most of the channels. Only the non-selective channels require empirical equations to describe their unusual linear I/V profile. The HGSS model (Hansen, Gradmann, Sanders and Slayman) is based on cyclic enzyme-mediated transport. This modelling allowed quantitative estimates of the stress responses described in Chap. 3. The pump and H+/OH− state produce “pH banding”, where these transporters dominate on different patches of the long cylindrical Characeae internodes. Banding allows a greater supply of dissolved inorganic carbon (DIC) for photosynthesis in the chloroplasts, as well as excretion of the surplus OH− formed by this process. pH banding has been adopted by aquatic angiosperms, roots of land plants and pollen tubes, confirming the importance of the Characeae as a model system. As well as these transporters, Characeae also provided information on 2H+/Cl− symporters, amine, nitrate and urea transport, phosphate transport and Na+/K+ transporters. Knowledge about nitrogen and phosphate transporters is important for agricultural production. Characeae also provided a good system for the study of aquaporins and water transport. The “difficult to access” tonoplast membrane was studied using vacuolar perfusion, plasma membrane permeabilisation and cytoplasmic droplets. This final experimental system allowed detailed patch-clamp studies of large conductance K+ channels.
Alba Vicente - One of the best experts on this subject based on the ideXlab platform.
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european charophyte evolution across the cretaceous paleogene boundary
Palaeogeography Palaeoclimatology Palaeoecology, 2019Co-Authors: Alba Vicente, Zoltan Csikisava, Carles MartinclosasAbstract:Abstract The Cretaceous–Paleogene (K/Pg) boundary has traditionally been considered a key moment in charophyte evolution, marked by the extinction of two important Mesozoic families, the PoroCharaceae and the Clavatoraceae, and a major turnover within the Characeae. However, new data presented here suggest that one species of the European PoroCharaceae (based on gyrogonites) and one species of the Clavatoraceae (based on thalli), persisted into the basal Danian. In addition, a taxonomic revision of the Characeae, coupled with an updated biostratigraphy, shows that this family underwent a step-wise extinction during the latest Cretaceous with only a small number of species becoming extinct at the K/Pg boundary. As a result, changes in charophyte floras around the K/Pg boundary in Europe cannot be considered to represent a major turnover in charophyte evolution. Its effects were more comparable to a normal stage boundary event rather than to a major erathem boundary one. Similar disappearance patterns at the K/Pg boundary have also been recorded in other taxa, including fish and amphibians, showing that aquatic freshwater biotas may somehow be resilient to catastrophic events such as those that occurred during the K/Pg crisis.
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on the earliest occurrence of tolypella section tolypella in the fossil record and the age of major clades in extant Characeae
Botany Letters, 2018Co-Authors: Carles Martinclosas, Alba Vicente, Josep Sanjuan, Jordi Perezcano, Telm BoverarnalAbstract:The genus Tolypella is considered the basal-most characean genus according to modern molecular phylogenies. Its fossil record, however, provides contradictory evidence since fossil Tolypella sectio...
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On the earliest occurrence of Tolypella section Tolypella in the fossil record and the age of major clades in extant Characeae
Botany Letters, 2017Co-Authors: Carles Martín-closas, Jordi Pérez-cano, Alba Vicente, Josep Sanjuan, Telm Bover-arnalAbstract:The genus Tolypella is considered the basal-most characean genus according to modern molecular phylogenies. Its fossil record, however, provides contradictory evidence since fossil Tolypella section Tolypella has its first fossil occurrence in the Late Cretaceous, about the same time as the first occurrences of other genera of living characeans, i.e. Chara, Lamprothamnium, Nitellopsis and Lychnothamnus which are considered more derived. In this study, the first occurrence of Tolypella sp. aff. T. grambastii subsp. arctica (Tolypella section Tolypella) is now documented from a lacustrine bed, in the Lower Cretaceous of the Garraf Massif (Catalonia, Spain), ca. 125.0 Ma old. This indicates that Tolypella s.s. is indeed a very old genus and that its first fossil record should be extended back at least 55 million years. The first appearance of living Characeae in the fossil record correlates well with the topology of molecular phylogenies. The basal genera Tolypella, Nitella and the ancestors of the e...