O gênero Cosmarium Corda ex Ralfs (Desmidiaceae, Zygnematophyceae) no estado de São Paulo: levantamento taxonômico das formas com parede celular decorada
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Data
2016-06-17
Autores
Biolo, Stefania [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As algas verdes conjugantes (Zygnematophyceae) apresentam extrema beleza estética dada à diversidade morfológica e a complexa simetria das células de seus espécimes representantes, o que tem atraído a atenção de pesquisadores por mais de 200 anos. A taxonomia clássica das desmídias baseada na morfologia das células vegetativas e na decoração da parede celular ainda provê informação taxonômica útil e importante em um contexto aplicado e crítico. Um dos gêneros mais antigos e também o mais rico taxonomicamente, Cosmarium Corda ex Ralfs, conta com mais de 1.500 táxons já descritos incluindo espécies, variedades e formas taxonômicas. Como continuidade dos esforços encetados para o conhecimento da biodiversidade algal do Estado de São Paulo complementou-se, no presente estudo, o inventário florístico das espécies, variedades e formas taxonômicas de Cosmarium, desta vez com ênfase nos exemplares que possuem parece celular decorada. O material analisado consistiu em 124 amostras tombadas no acervo do Herbário Científico do Estado “Maria Eneyda P. Kauffmann Fidalgo” (SP) do Instituto de Botânica da Secretaria do Meio Ambiente do Estado de São Paulo, provenientes de 104 municípios. Adicionalmente, os materiais em literatura anteriormente publicados e passíveis de reidentificação também foram incluídos. Foram identificados 98 táxons de Cosmarium ocorrentes no Estado de São Paulo, sendo dois apenas em nível gênero e os demais em níveis específico e infraespecífico, dos quais 37 são variedades não-típicas de suas respectivas espécies e 10 formas taxonômicas igualmente não típicas, porém, de suas variedades. Quatro expressões morfológicas não nomeadas podem consistir novas variedades à Ciência. Destes registros, 21 são citados pela primeira vez para o Estado de São Paulo e 24 para o Brasil. Os táxons mais bem distribuídos foram Cosmarium punctulatum Brébisson var. punctulatum (ocorrente em 37 municípios), C. subspeciosum Nordstedt var. subspeciosum (35 municípios), C. blyttii Wille var. blyttii f. blyttii (34 municípios) e C. margaritatum (P.Lundell) J.Roy & Bisset var. margaritatum f. margaritatum (31 municípios). O presente estudo elevou a distribuição geográfica e o conhecimento de Cosmarium no Estado de São Paulo para 81 municípios, face aos 11 até então constantes em literatura. Adicionando um considerável número de descrições e trazendo à luz cinco formas que podem consistir novas variedades e espécies à Ciência, a presente pesquisa demonstrou a profunda importância dos levantamentos taxonômicos para o conhecimento da biodiversidade. Ademais, colaborou para o fortalecimento da taxonomia clássica para as algas desmidiáceas, com base na análise morfológica de material vegetativo, visto que formas reprodutivas sexuadas não foram encontradas em todas as amostras examinadas. A taxonomia do gênero Cosmarium continua extremamente complicada e jamais foi realizada uma avaliação criteriosa das características morfológicas para definir quais são diacríticas e quais diagnósticas. Mesmo os estudos filogenéticos estribados nas ferramentas da biologia molecular ainda não solucionaram a taxonomia do gênero no âmbito cladístico. Definir critérios que permitam um esquema sistemático lógico do gênero Cosmarium ainda não foi possível. Desta forma, sugere-se manter a atual composição de espécies, variedades e formas taxonômicas e providenciar descrição e ilustrações bem detalhadas e informativas para cada uma.
Green conjugating algae (Zygnematophyceae) show some exciting aesthetic beauty due to its morphological diversity and the complex symmetry of their cells, what explains their continuous attention by taxonomists for over 200 years. Desmids classic taxonomy based on morphology of vegetative cells and the cell wall decoration still provides usefull and important taxonomic information in an applied and critical context. Cosmarium Corda ex Ralfs, one of the oldest genera and very rich taxonomically includes more than 1,500 already described taxa including species, varieties and taxonomic formae. Considering all effort on the knowledge of the São Paulo State algal biodiversity, the floristic survey of Cosmarium species, varieties and taxonomic formae was completed, highlighting forms with decorated cell wall. Material studied involved 124 samples belonging to the scientific collection of the Herbário Científico do Estado “Maria Eneyda P. Kauffmann Fidalgo” (SP) of the Instituto de Botânica, Secretaria do Meio Ambiente do Estado de São Paulo, which were collected from 104 municipalities in the State São Paulo. All material in the specialized literature whose reidentification was possible was also included. Ninety eight Cosmarium taxa were identified, two at the genus level and the remaining ones at the species and infraspecific levels, 37 varieties that are not the typical of their respective species and 10 taxonomic formae are also not the typical, but of their respective varieties. Four unnamed morphological expressions could be new varieties to be formally described in the near future. Twenty one of the present 98 records are cited for the first time to São Paulo State and 24 to Brazil. The best geographically distributed taxa were Cosmarium punctulatum Brébisson var. punctulatum (occurring in 37 municipalities), C. subspeciosum Nordstedt var. subspeciosum (35 municipalities), C. blyttii Wille var. blyttii f. blyttii (34 municipalities) and C. margaritatum (P.Lundell) J.Roy & Bisset var. margaritatum f. margaritatum (31 municipalities). Present study improved the geographical distribution and knowledge of genus Cosmarium in São Paulo State to 81 municipalities, compared to the 11 citations up to now in the literature. By adding a considerable number of descriptions and bringing to light five morphological expressions that may represent new species and taxonomic varieties to Science, the present survey evidenced the paramount importance of the florististic surveys to the knowledge of biodiversity. Furthermore, present survey colaborated for the strenghtening of the classical taxonomy of desmids based on the morphological analysis of vegetative material, since sexual reproductive forms were not found in all samples examined. Cosmarium taxonomy remains extremely complicated, and a criterious evaluation of the morphological characteristics used was never carried out to define which are diacritical and which are diagnostic. Even the phylogenetic studies using molecular biology tools did not help in the genus taxonomy from the cladistics point of view. Definition of criteria that would allow development of a Cosmarium systematic scheme was not yet been possible. Thus, it is presently suggested to maintain the present composition of species, varieties and taxonomic formae and to provide well detailed descriptions and illustrations that would be informative for each one.
Green conjugating algae (Zygnematophyceae) show some exciting aesthetic beauty due to its morphological diversity and the complex symmetry of their cells, what explains their continuous attention by taxonomists for over 200 years. Desmids classic taxonomy based on morphology of vegetative cells and the cell wall decoration still provides usefull and important taxonomic information in an applied and critical context. Cosmarium Corda ex Ralfs, one of the oldest genera and very rich taxonomically includes more than 1,500 already described taxa including species, varieties and taxonomic formae. Considering all effort on the knowledge of the São Paulo State algal biodiversity, the floristic survey of Cosmarium species, varieties and taxonomic formae was completed, highlighting forms with decorated cell wall. Material studied involved 124 samples belonging to the scientific collection of the Herbário Científico do Estado “Maria Eneyda P. Kauffmann Fidalgo” (SP) of the Instituto de Botânica, Secretaria do Meio Ambiente do Estado de São Paulo, which were collected from 104 municipalities in the State São Paulo. All material in the specialized literature whose reidentification was possible was also included. Ninety eight Cosmarium taxa were identified, two at the genus level and the remaining ones at the species and infraspecific levels, 37 varieties that are not the typical of their respective species and 10 taxonomic formae are also not the typical, but of their respective varieties. Four unnamed morphological expressions could be new varieties to be formally described in the near future. Twenty one of the present 98 records are cited for the first time to São Paulo State and 24 to Brazil. The best geographically distributed taxa were Cosmarium punctulatum Brébisson var. punctulatum (occurring in 37 municipalities), C. subspeciosum Nordstedt var. subspeciosum (35 municipalities), C. blyttii Wille var. blyttii f. blyttii (34 municipalities) and C. margaritatum (P.Lundell) J.Roy & Bisset var. margaritatum f. margaritatum (31 municipalities). Present study improved the geographical distribution and knowledge of genus Cosmarium in São Paulo State to 81 municipalities, compared to the 11 citations up to now in the literature. By adding a considerable number of descriptions and bringing to light five morphological expressions that may represent new species and taxonomic varieties to Science, the present survey evidenced the paramount importance of the florististic surveys to the knowledge of biodiversity. Furthermore, present survey colaborated for the strenghtening of the classical taxonomy of desmids based on the morphological analysis of vegetative material, since sexual reproductive forms were not found in all samples examined. Cosmarium taxonomy remains extremely complicated, and a criterious evaluation of the morphological characteristics used was never carried out to define which are diacritical and which are diagnostic. Even the phylogenetic studies using molecular biology tools did not help in the genus taxonomy from the cladistics point of view. Definition of criteria that would allow development of a Cosmarium systematic scheme was not yet been possible. Thus, it is presently suggested to maintain the present composition of species, varieties and taxonomic formae and to provide well detailed descriptions and illustrations that would be informative for each one.
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Palavras-chave
Biodiversidade, Desmídias, Ficoflora, Taxonomia, Brasil, Biodiversity, Algalflora, Desmids, Brazil