Mariângela Menezes

New Brazilian Floristic List Highlights Conservation Challenges

A comprehensive new inventory of Brazilian plants and fungi was published just in time to meet a 2010 Convention on Biological Diversity target and offers important insights into this biodiversitys global significance. Brazil is the home to the worlds richest flora (40,989 species; 18,932 endemic) and includes two of the hottest hotspots: Mata Atlântica (19,355 species) and Cerrado (12,669 species). Although the total number of known species is one-third lower than previous estimates, the absolute number of endemic vascular plant species is higher than was previously estimated, and the proportion of endemism (56%) is the highest in the Neotropics. This compilation serves not merely to quantify the scale of the challenge faced in conserving Brazils unique flora but also serves as a key resource to direct action and monitor progress. Similar efforts by other megadiverse countries are urgently required if the 2020 targets of the Convention on Biological Diversity and the Global Strategy for Plant Conservation are to be attained.

Taxonomic remarks on planktonic phytoflagellates in a hypertrophic tropical lagoon (Brazil)

The phototrophic flagellate flora of the Barra Lagoon (22°57′ S and 42°47′ W), Rio de Janeiro State, southeastern Brazil, is described. The lagoon is a shallow, oligohaline, hypertrophic ecosystem in which Cyanophyceae, Chlorophyceae and phytoflagellates are dominant. Between October 1990 and August 1993, weekly integrated samples were collected from a bay, using a plexiglass tube, 8 cm diameter and 1m length. All identifications, descriptions and measurements were carried out on live or in Lugol-fixed material. A total of 30 taxa, belonging to Euglenophyceae (5), Cryptophyceae (7), Raphidophyceae (1), Dinophyceae (4), Chrysophyceae (3), Prymnesiophyceae (2), Prasinophyceae (7) and Chlorophyceae (1) were identified. All the phytoflagellate species identified have been recorded previously from temperate sites. Nine of them were registered in a tropical water for the first time, suggesting that they have much broader distributions. Gymnodinium sanguineum, Pavlova lutheri and Pyramimonas grossii were the most frequently observed phytoflagellates in this study. The seasonal occurrence and some environmental requirements of selected phytoflagellates species are discussed.

Phytoplankton composition and functional groups in a tropical humic coastal lagoon, Brazil

Este trabalho apresenta a composicao e os grupos funcionais do fitoplâncton da lagoa Comprida, uma lagoa costeira tropical humica localizada no sudeste brasileiro. Foi registrado um total de 28 taxons distribuidos em oito divisoes taxonomicas: 26% Heterokontophyta, 21% Chlorophyta, 21% Cyanophyta, 14% Bacillariophyta, 14% Cryptophyta e 4% Prymnesiophyta. Vinte e tres taxons foram identificados em nivel especifico e intraespecificos, dos quais quatro constituem novos registros para o Brasil e dois para o estado do Rio de Janeiro. O fitoplâncton da lagoa Comprida esteve constituido por alguns flagelados, mas tambem por organismos picoplanctonicos eucariontes e procariontes, cianobacterias filamentosas e algumas diatomaceas. A biomassa foi menor que a comumente encontrada em outros sistemas lacustres e mostrou uma notavel variabilidade temporal. Em relacao aos grupos funcionais, as populacoes foram agrupadas em oito grupos: Q, Z, E, N, X3, X2, S1 e Y, muitos dos quais tipicos de sistemas oligo ou mesotroficos, tolerantes a baixas concentracoes de nutrientes e sensiveis a baixos valores de pH.

How diverse are planktonic cryptomonads in Brazil? Advantages and difficulties of a taxonomic-biogeographical approach

We compare ‘temperate data’ with information contained in 49 surveys of cryptomonads from Brazilian tropical regions. These surveys contain a total of 351 records relative to a total of 38 taxa at the species level or below. All taxa were identified using traditional morphological characters visible with the light microscope. Two taxa appear to be new species, and amongst the known species Cryptomonas erosa Ehrenberg is the most frequently recorded one. To date two species of Pseudocryptomonas Bicudo & Tell (all containing multiple photosynthetic endosymbionts/chloroplasts) and the species Cryptomonas brasiliensis Castro, C. Bicudo D. Bicudo have not been found outside Brazil. With respect to their geographical distribution in Brazilian tropical regions, cryptomonads are better represented in reservoirs and coastal lagoons located in the south-eastern part of the country. Some species appear to be restricted to brackish coastal ecosystems (oligo- to mesohaline and meso- to eutrophic waters). There are only four records of marine cryptomonads. A comparative study of three different kinds of shallow aquatic environments in Brazil — north-eastern reservoirs, a flood-plain Amazonian lake, and brackish lagoons on the south-eastern coast — shows that cryptomonads are to be found constantly, and their species number density, and biomass are generally low (usually < 10%) in relation to the other phytoplankton. The case of Plagioselmis Butcher emend. Novarino, Lucas & Morrall, amongst others, exemplifies the great difficulties encountered while attempting to interpret biogeographical information based on light microscopy within the context of a modern systematic and taxonomic framework based on electron microscopy.

Taxonomy and ecology of Synedropsis roundii sp. nov. (Bacillariophyta) from a tropical brackish coastal lagoon, south-eastern Brazil

Abstract A new Synedropsis species is described from a coastal tropical lagoon in south-eastern Brazil. This species has a single chloroplast in both views of the valve, apical pore fields composed of three slits, and uniseriate striae. It is planktonic and was found in brackish water. Synedropsis roundii is the eighth Synedropsis species to be described and the first to be found in a tropical region. We studied the seasonal dynamics of S. roundii, which can form blooms in the coastal Imboassica Lagoon, Rio de Janeiro stale, Brazil. Continuous mixing of this shallow environment is suggested to be an important physical factor determining the success of the species. Availability of soluble reactive silicon is thought to be the main factor regulating the large biomass fluctuations. In the classification of Reynolds in 1997 (Vegetation processes in the pelagic: a model for ecosystem theory. Ecology Institute, Oldendorf, Germany, 371 pp.), S. roundii appears to belong to D-assemblage, a set of small and fast-growing diatoms, well represented in small, shallow and enriched waters. We also offer a tentative habitat template for S. roundii.

IDENTIFICATION OF THE TOXIC ALGA ALEXANDRIUM TAMIYAVANICHI (DINOPHYCEAE) FROM NORTHEASTERN BRAZIL: A COMBINED MORPHOLOGICAL AND rDNA SEQUENCE (PARTIAL LSU AND ITS) APPROACH1

Morphological and phylogenetic analyses and sequencing of the partial LSU gene and internal transcribed spacer (ITS) regions of the rDNA gene were combined to study toxic strains of Alexandrium tamiyavanichi Balech collected from northeastern Brazilian coastal waters. All specimens were identified with A. tamiyavanichi mainly based on the shape of the anterior sulcal plate (S.a.), which was the most conservative character. Among the specimens studied, 8% did not conform to the morphological description of A. tamiyavanichi. The occurrence of transitory states between A. tamiyavanichi and Alexandrium cohorticula (Balech) Balech tended to confirm that both species are conspecific. The posterior sulcal plate (S.p.) was not a good taxonomic character as variability in its shape did not allow a clear assignment of specimens from the same clonal isolate to either morphologically defined species. Phylogenetic analyses confirmed the overall validity of morphological characters to delineate the evolutionary relationships among the clades of Alexandrium species analyzed here, indicating that A. tamiyavanchi is a valid species according to the morphological species concept. This analysis showed that the Brazilian strains form a monophyletic clade with Asiatic strains of A. tamiyavanichi, but with enough genetic distance to argue for long‐term separation and isolation of locally established populations, extending the known biogeographic range of this species. On the higher phylogenetic level, our data also indicate that Alexandrium tropicale Balech forms part of the clade otherwise consisting of the morphologically defined freterculus group, and this A. tamiyavanichi/tropicale/fraterculus (Balech) Balech clade (including species from the formerly termed tropical Asian [TROP] clade) may be considered as a sister group of the Alexandrium tamarense species complex.

Prorocentrum lima from the South Atlantic: Morphological, molecular and toxicological characterization

Morphological descriptions using light and scanning electron microscopy and molecular characterization of two Prorocentrum lima strains (UNR-01 and UNR-09) isolated from Armação dos Búzios, Rio de Janeiro, Brazil are provided. Okadaic acid (OA), dinophysistoxin-1 (DTX1) and DTX2 production by strain UNR-01 was investigated using liquid chromatography with mass spectrometry. Toxins were extracted from heat-treated (boiled) and non-boiled cell pellets to obtain respective quantities of free and total OA and DTX1. Growth parameters (growth rate and mean generation time) were determined for strain UNR-01. Prorocentrum lima cells were oblong-to-ovate in shape, broad in the middle region, and narrow at the anterior end. The periflagellar area was triangular, set into a V-shaped depression and was composed of eight periflagellar platelets of different sizes. The morphology fits well the characterization of the species isolated from elsewhere. Phylogenetic analysis based on internal transcribed spacer - ITS - and D1-D3 large subunit - LSU - of ribosomal RNA gene sequences revealed that both strains were identical and closely related to P. lima isolates from the Caribbean Sea and USA. The growth rate of strain UNR-01 was 0.24divday-1. OA concentrations were on average 15.2 and 38.5pg[OA]cell-1 for heat-treated and non-treated cells respectively, while DTX1 mean concentration was 0.5pg[DTX1]cell-1 for both heat-treated and non-treated cells. DTX2 was not detected. To date, these are the first strains of P. lima from the south Atlantic that have been characterized.

Phylogeny and Classification of Euglenophyceae: A Brief Review

Euglenophyceae (phototrophic euglenids) are an important lineage within the Euglenida, Euglenozoa. Most of the approximately 3,000 described species are free-living, phototrophic, unicellular flagellates with one to several plastids of secondary origin, three bounding membranes and chlorophylls a and b; but, the lineage also includes colorless species that lost their photosynthesizing capability. They show a typical cell membrane consisting of parallel proteinaceous strips and microtubules located underneath the plasma membrane, and discoid mitochondrial cristae. Euglenozoa are a monophyletic group that includes, besides Euglenida, the Kinetoplastidea, Diplonomea and Symbiontida. Since the class Euglenophyceae was proposed, its classification system has undergone several revisions, mainly after the adoption of molecular techniques. This article summarizes recent advances in the phylogeny and classification of the phototrophic euglenids, aiming at understanding the situation of the group within the phylum Euglenozoa, as well as its evolutionary relationships and the changes in its taxonomic classification. The current status of the group, as well as the limitations derived from the lack of inclusion of tropical strains in phylogenetic studies is briefly discussed.

Coleção de microalgas de ambientes dulciaquícolas naturais da Bahia, Brasil, como potencial fonte para a produção de biocombustíveis: uma abordagem taxonômica

O presente trabalho envolveu a identificacao taxonomica de especies nativas de microalgas (isoladas de ecossistemas dulciaquicolas localizados nos arredores de Salvador, Bahia) integrantes da Colecao de Microalgas dulciaquicolas do LABIOMAR/IB/UFBA, visando estudos taxonomicos mais aprofundados (ultraestruturais e moleculares) e experimentos que possam avaliar sua capacidade para suprir cadeias produtivas de biocombustiveis. As coletas foram realizadas nos arredores de Salvador, Bahia, Brasil. A identificacao das especies foi efetuada com base em caracteres morfologicos. Foram identificados 19 taxons, 12 em nivel de especie e nove em nivel de genero, sendo 14 Chlorophyceae (Chlamydomonas sp1, Chlamydomonas sp2, Chlamydomonas sp3, Chlamydocapsa bacillus (Teiling) Fott, Chlorococcum sp1, Chlorococcum sp2), Coelastrum indicum Turn.. Coelastrum microporum Nageli, Desmodesmus brasiliensis (Bohl.) Hegew, Scenedesmum obliquus (Turpin) Kutz, Ankistrodesmus falcatus (Corda) Ralfs, Ankistrodesmus fusiformis Corda, Kirchneriella lunaris (Kirchner.) Mobius, Pseudokirchneriella subcapitata (Korshikov) F. Hindak), tres Trebouxiophyceae (Botryococcus braunii Kutz., Botryococcus terribilis Komarek et Marvan e Chlorella vulgaris Beijerinck), uma Bacillariophyceae (Nitzschia sp.) e uma Cyanobacteria (Synechocystis sp.).

Morphology and phylogeny of Prorocentrum caipirignum sp. nov. (Dinophyceae), a new tropical toxic benthic dinoflagellate

A new species of toxic benthic dinoflagellate is described based on laboratory cultures isolated from two locations from Brazil, Rio de Janeiro and Bahia. The morphology was studied with SEM and LM. Cells are elliptical in right thecal view and flat. They are 37-44μm long and 29-36μm wide. The right thecal plate has a V shaped indentation where six platelets can be identified. The thecal surface of both thecal plates is smooth and has round or kidney shaped and uniformly distributed pores except in the central area of the cell, and a line of marginal pores. Some cells present an elongated depression on the central area of the apical part of the right thecal plate. Prorocentrum caipirignum is similar to Prorocentrum lima in its morphology, but can be differentiated by the general cell shape, being elliptical while P. lima is ovoid. In the phylogenetic trees based on ITS and LSU rDNA sequences, the P. caipirignum clade appears close to the clades of P. lima and Prorocentrum hoffmannianum. The Brazilian strains of P. caipirignum formed a clade with strains from Cuba, Hainan Island and Malaysia and it is therefore likely that this new species has a broad tropical distribution. Prorocentrum caipirignum is a toxic species that produces okadaic acid and the fast acting toxin prorocentrolide.