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Em 28 de fevereiro de 2024, Beatriz Brunelli de Souza, aluna de doutorado do programa de P\u00f3s-Gradua\u00e7\u00e3o em Biodiversidade Vegetal e Meio Ambiente do Instituto de Pesquisas Ambientais IPA\u2013 SP., bolsista CAPES, defendeu sua tese de Doutorado intitulada, \u201cFilogenia, aspectos evolutivos e distribui\u00e7\u00e3o geogr\u00e1fica do complexo Laurencia<\/em> (Ceramiales, Rhodophyta)\u201d, no modo virtual.<\/p>\n A banca examinadora foi presidida pela sua orientadora, Dra. Mutue Toyota Fujii (Instituto de Pesquisas Ambientais – IPA) e composta pela Dra.\u00a0<\/sup>Daniela Milstein (Universidade Federal de S\u00e3o Paulo \u2013 UNIFESP), Dr.\u00a0\u00a0<\/sup>Jos\u00e9 Marcos de Castro Nunes (Universidade Federal da Bahia \u2013 UFBA), Dra.\u00a0<\/sup>L\u00edgia Collado-Vides (Florida Internacional University – FIU) e pela Dra. Mariana Cabral de Oliveria (Universidade de S\u00e3o Paulo – USP).<\/p>\n O g\u00eanero Micrasterias foi descrito por Carl Agardh em 1827 e validado por John Ralfs em 1848. A taxonomia deste g\u00eanero est\u00e1 baseada apenas nas caracter\u00edsticas morfol\u00f3gicas de suas c\u00e9lulas, tais como: forma, incis\u00f5es celulares, dimens\u00f5es, planos de simetria, ornamenta\u00e7\u00e3o da parede celular e configura\u00e7\u00e3o dos cloroplast\u00eddios. O n\u00famero de lobos separa os representantes do g\u00eanero em trilobados (tr\u00eas lobos e duas incis\u00f5es) e pentalobados (cinco lobos e quatro incis\u00f5es). Muitas esp\u00e9cies classificadas no g\u00eanero apresentam ampla varia\u00e7\u00e3o morfol\u00f3gica em n\u00edvel populacional, provocando confus\u00e3o na descri\u00e7\u00e3o de in\u00fameras variedades e formas taxon\u00f4micas. Duas esp\u00e9cies de Micrasterias s\u00e3o facilmente distinguiveis, M. denticulata e M. thomaprimeira foi proposta em 1835 por A. Br\u00e9bisson e caracteriza-se pelas proje\u00e7\u00f5es arredondadas na base dos segmentos e sem proemin\u00eancias superficiais na parede celular. Micrasterias thomasiana foi descrita em 1862 por W. Archer e apresenta semelhan\u00e7a morfol\u00f3gica com M. denticulata, por\u00e9m, exibe diferen\u00e7a no tamanho celular e em caracter\u00edsticas da margem terminal dos l\u00f3bulos de \u00faltima ordem e proje\u00e7\u00f5es proemin\u00eancias superficiais na parede celular. As cepas estudadas dessas esp\u00e9cies exibiram ampla varia\u00e7\u00e3o quanto \u00e0s medidas lineares e \u00e0 forma celular. As medidas lineares ora obtidas revelaram diferen\u00e7as significativas entre cepas e entre indiv\u00edduos de uma mesma cepa, ressaltando a necessidade de medidas padronizadas e inclus\u00e3o de novos atributos morfol\u00f3gicos para a caracteriza\u00e7\u00e3o morfol\u00f3gica de esp\u00e9cies semelhantes. Como os representantes de ambas as esp\u00e9cies possuem morfologia bastante semelhante, a inclus\u00e3o de seis novos atributos aliados aos tr\u00eas j\u00e1 utilizados na literatura complementou sua caracteriza\u00e7\u00e3o auxiliando significativamente na identifica\u00e7\u00e3o das diferen\u00e7as entre as cepas e, ainda melhor, entre os esp\u00e9cimes de cada esp\u00e9cie analisada. A an\u00e1lise das cepas usando duas abordagens morfom\u00e9tricas distintas (morfometrias linear e geom\u00e9trica) concluiu que a ado\u00e7\u00e3o de novos atributos morfol\u00f3gicos (obten\u00e7\u00e3o de medidas lineares) e a an\u00e1lise da forma celular constitu\u00edram ferramentas essenciais para separar esp\u00e9cies morfologicamente pr\u00f3ximas, problema taxon\u00f4mico e nomenclatural crucial. As oito cepas estudadas foram originalmente identificadas em suas respectivas cole\u00e7\u00f5es de cultivo como representantes de M. denticulata e M. thomasiana. Embora os indiv\u00edduos de algumas dessas cepas apresentem caracter\u00edsticas morfol\u00f3gicas diagn\u00f3sticas de ambas as esp\u00e9cies em pauta, os dados moleculares e filogen\u00e9ticos obtidos permitiram reconhecer que as oito cepas analisadas constituem entidades taxon\u00f4micas distintas dos pontos de vista filogen\u00e9tico e molecular. Novas proposi\u00e7\u00f5es e emendas taxon\u00f4micas dever\u00e3o ser providenciadas em futuro breve para designar e classificar estas novas esp\u00e9cies dentro da linhagem Micrasterias.<\/p>\n Palavras-chave:<\/strong> Desm\u00eddias, Zygnematophyceae, Micrasterias, Taxonomia, Biologia Molecular<\/p>\n ABSTRACT<\/strong><\/p>\n Micrasterias was described by Carl Agardh in 1827 and validated by John Ralfs in 1848. The taxonomy of this genus is based solely on the morphological characteristics of its cells, such as shape, cell incisions, dimensions, planes of symmetry, cell wall ornamentation, and chloroplast configuration. The number of lobes separates the representatives of the genus into trilobed (three lobes and two incisions) and pentalobed (five lobes and four incisions). Many species classified within the genus exhibit wide morphological variation at the population level, causing confusion in the description of numerous varieties and taxonomic forms. Two species of Micrasterias are easily distinguishable, M. denticulata and M. thomasiana. The first was proposed in 1835 by A. Br\u00e9bisson and is characterized by rounded projections at the base of the segments and the absence of prominent surface features on the cell wall. Micrasterias thomasiana was described in 1862 by W. Archer and shows morphological similarity to M. denticulata, but differs in cell size and in the characteristics of the terminal margin of the lobes of the last order and prominent surface projections on the cell wall. The strains studied of these species showed wide variation in terms of linear measurements and cell shape. The linear measurements obtained revealed significant differences between strains and between individuals of the same strain, highlighting the need for standardized measurements and the inclusion of new morphological attributes for the characterization of similar species. As the representatives of both species have quite similar morphology, the inclusion of six new attributes, along with the three already used in the literature, complemented their characterization, significantly aiding in identifying the differences between the strains and, even better, between the specimens of each species analyzed. The analysis of the strains using two distinct morphometric approaches (linear and geometric morphometries) concluded that the adoption of new morphological attributes (obtaining linear measurements) and cell shape analysis were essential tools to separate morphologically similar species, a crucial taxonomic and nomenclatural issue. The eight strains studied were originally identified in their respective culture collections as representatives of M. denticulata and M. thomasiana. Although individuals of some of these strains display diagnostic morphological characteristics of both species, the molecular and phylogenetic data obtained allowed recognition that the eight analyzed strains constitute distinct taxonomic entities from phylogenetic and molecular points of view. New taxonomic propositions and amendments should be provided in the near future to designate and classify these new species within the Micrasterias lineage.<\/p>\n Keywords:<\/strong> Desmids, Zygnematophyceae, Micrasterias, Taxonomy, Molecular Biology.<\/p>\n
\nFilogenia, aspectos evolutivos e distribui\u00e7\u00e3o geogr\u00e1fica do complexo Laurencia<\/em> (Ceramiales, Rhodophyta)<\/h3>\n
\nRESUMO<\/strong><\/h4>\n
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(indispon\u00edvel para consulta)<\/p>\n