Microturbellarians (Platyhelminthes and Acoelomorpha) in Brazil: invisible organisms?

Abstract

Microturbellarians typically belong to the benthos and may occur in a wide variety of environments. They are abundant in freshwater and marine ecosystems and may occur in moist terrestrial habitats. However, turbellarians are seldom taken into account in studies of biodiversity. Most studies on Brazilian microturbellarians had taxonomical purposes and were done in the years 1940-1950. Thus, information on their occurrence and ecological aspects are dispersed throughout several papers. We intend here to summarize the biogeographical distribution and ecological aspects of microturbellarians recorded for Brazil, indicating the main gaps in their knowledge and possible actions to enhance studies on this group. There are 239 species of microturbellarians registered for Brazil, with records distributed in 12 states. However, just three states located in southern Brazil have records of 94% of microturbellarian species. Thus, knowledge on the systematics and geographical distribution of Brazilian microturbellarians clearly reflect the scientific activity over many years or decades in two states of southeastern and southern Brazil. Considering the scant information on this group in Brazil, which is also the situation of the Neotropical microturbellarians in general, some actions should be proposed. First, it would be necessary to sample in the diverse biomes, as well as in the various river and sea basins, based on standardized sampling protocols. Second, it would be necessary to encourage diverse research groups to include microturbellarians and/or turbellarians in general into biodiversity inventories and studies on community structure of invertebrates. Third, it is necessary to increase the number of research groups on microturbellarians, in order to augment the studies on their morphology, systematics, and ecology. Considering their abundance, species richness and ecological importance in aquatic environments, despite some peculiarities regarding their sampling, sorting and identification procedures, the challenge to study microturbellarians and enhance knowledge about them in Brazilian ecosystems should be faced.Keywords: Platyhelminthes, species diversity, Neotropical region, systematics, ecology. Microturbelários (Platyhelminthes e Acoelomorpha) no Brasil: organismos invisíveis? ResumoMicroturbelários são tipicamente bentônicos e podem ocorrer em uma ampla variedade de ambientes. São abundantes em ecossistemas marinhos e de água doce, podendo ocorrer em ambientes terrestres úmidos. Entretanto, turbelários raramente são considerados em estudos de diversidade. A maioria dos estudos sobre microturbelários brasileiros tiveram propósito taxonômico e foram realizados nos anos 1940-1950. Assim, informações sobre ocorrência e aspectos ecológicos estão dispersos em diversos artigos. O objetivo deste trabalho é sumarizar a distribuição biogeográfica e aspectos ecológicos dos microturbelários registrados para o Brasil, indicando as principais lacunas do conhecimento e possíveis ações para ampliar estudos sobre esse g...

Six freshwater microturbellarian species (Platyhelminthes) in permanent wetlands of the Coastal Plain of southern Brazil: new records, abundance, and distribution

“…The diversity and distribution of microturbellarians are poorly known in the Neotropical region, and most knowledge is restricted to taxonomic works (Noreña et al 2004, Brusa 2006, Damborenea et al 2007, Brusa et al 2008, Adami et al 2012, Martínez-Aquino et al 2014, Braccini et al 2016. In the present work, we report new records of 6 microturbellarian species, 3 of them previously reported only from their type localities.…”

“…An extensive area of the Neotropical region, as well as other parts of the world, has no or only scattered taxonomic and/or ecological studies , Schockaert et al 2008, Martínez-Aquino et al 2014, Braccini et al 2016, and thus, the known diversity of this group is seemingly highly underestimated.…”

“…In southern Brazil, 52 microturbellarian species were recorded in freshwater ecosystems (Braccini et al 2016).…”

“…The distribution of microturbellarians in the Neotropical region is mainly known from taxonomic studies, most of which were done in Argentina and Brazil (e.g. Marcus 1945a, b, 1946, 1948, 1950, 1952, Noreña et al 2004, Brusa 2006, Damborenea et al 2007, Brusa et al 2008, Adami et al 2012, Martínez-Aquino et al 2014, Braccini et al 2016. In Brazil, the distribution of microturbellarian species is mainly known from taxonomical works done by Marcus (e.g.…”

“…, 1950Marcus (e.g. , 1952 in the state of São Paulo, as well as from inventories and studies on community ecology done in the state of Rio Grande do Sul (Braccini et al 2016). There 239 species of microturbellarians recorded from Brazil, 108 of them…”