Occurrence of Arcellidae (Amorphea, Arcellinida) in a coastal stream in the State of Rio de Janeiro

Abstract

The aim of this study was to elaborate a taxonomic survey on the testate amoebae of the Family Arcellidae in coastal streams in the State of Rio de Janeiro. Six samplings were conducted in Ubatiba coastal stream (Maricá, RJ). In total, 130 liters water were filtered through a conical net of 60-μm mesh and preserved in 4% formalin. Organisms were identified with the aid of an inverted trinocular microscope. The morphological characteristics (lobose testate amoebae with shell composed of granular chitinoid elements) of each species were recorded. The species were described and illustrated. For the verification of new taxa records of Arcellidae in Rio de Janeiro and their distribution in Brazil, a search based on index articles by Scopus, Web of Science and Google Scholar using the keywords "tecamebas", "testate amoebae", "Arcella", "Arcellidae", "Brazil" and "Rio de Janeiro", was performed. Eight Arcellidae species were recorded. Some ecological and taxonomic information was provided. Due to the small amount of information on testate amoebae, this study is important because it reduces the knowledge gap regarding this community in the State of Rio de Janeiro. Furthermore, we suggest new studies on species identification to be conducted to expand regional knowledge about these organisms.

Análise da comunidade zooplanctônica em fitotelmos de bromélias, Rio de janeiro, Brasil

“…Conforme a literatura, o gênero Arcella é o que possui maior riqueza no plâncton, o que pode estar relacionado à forma de sua carapaça e sua composição, que lhe confere rigidez e resistência (LANSAC-TÔHA et al, 2007). Diferentemente, espécies do gênero Euglypha possuem carapaças que são auto secretadas e mais frágeis (MIRANDA et al, 2020), porém, o fato do fitotelmo ser um ambiente sem intensa movimentação pode facilitar a sua presença nesse local. Bem como, o sombreamento causado pela vegetação da área poderia evitar que a luz fosse prejudicial ao seu protoplasma, o que aparenta ser um problema para o gênero (LANSAC-TÔHA et al, 2007).…”

Testate amoebae: a review on their multiple uses as bioindicators

“…In order to feed and locomote, thecamoebians protrude filose or lobose pseudopodia through the test's aperture, the pseudostome (Cavalier-Smith 2004, Adl et al 2019. TA present key characteristics to act as reliable bioindicators, such as: 1) short life cycle that allows fast response to ecological change (Foissner 1999); 2) persistent test, that can resist fossilizing processes (Charman 2001, Patterson andKumar 2002); 3) sensitivity to a wide range of environmental variables (Nasser et al 2020); 4) great abundance and diversity in different environments (Foissner 1999, Lansac-Tôha et al 2007, Alves et al 2010, Miranda et al 2020; 5) worldwide distribution and established as bioindicators throughout different biotopes (Nasser et al, 2020). These organisms have been studied and used as bioindicators, answering to past and present conditions (Payne 2013, Roe and Patterson 2014 in the many biotopes in which those species inhabit.…”

Testate amoebae (Arcellinida and Euglyphida) from Pantanal dos Marimbús, Chapada Diamantina, Bahia state, Brazil, including new occurrences

“…These organisms are found in several habitats in Brazil, among the plankton, on aquatic macrophytes, and in sediments; their greatest richness of taxa has been recorded in plankton samples, largely due, however, to the larger numbers of studies undertaken in that habitat (Lansac-Tôha et al 2007). Most of those studies have been concentrated in the southern, southeastern, and midwestern regions Brazil, with less emphasis on the northern and northeastern regions (Lansac-Tôha et al 2007;Miranda et al 2015Miranda et al , 2020. According to Silva et al (2009), the lack of studies of these organisms in the Brazilian northeast is largely due to the paucity of taxonomic specialists for that group.…”