Composition and distribution of Darwinulidae (Crustacea, Ostracoda) in the alluvial valley of the upper Paraná River, Brazil

Abstract

The occurrence and abundance of darwinulid ostracods, as well as environmental factors influencing these patterns, were investigated in the alluvial valley of the upper Paraná River. Ostracods were sampled from several substrates, like littoral sediments and pleuston, which included several aquatic macrophytes species, from 31 localities (lentic and lotic) belonging to different riverine systems. Eight darwinulid species were found, representing all genera from this family. Alicenula serricaudata, Vestalenula pagliolii, and Penthesilenula brasiliensis were the most common species. Cluster analysis based on the composition and abundance of darwinulid communities revealed the presence of five associations. Darwinula stevensoni, Vestalenula botocuda, and Penthesilenula aotearoa were almost exclusive to lotic environments. A Mantel multiple test showed that the occurrence and distribution of darwinulid ostracods were significantly related to types of habitat and systems, but not to abiotic variables. It thus seems that the hydrodynamic fluctuations of these environments are probably more important to darwinulid distribution than the limnological characteristics. Keywords

Aquatic macroinvertebrates associated with Eichhornia azurea (Swartz) Kunth and relationships with abiotic factors in marginal lentic ecosystems (São Paulo, Brazil)

“…However, Higuti et al (2009) mentioned that the Ostracoda organisms are also abundant in the invertebrate communities associated with macrophytes in Neotropical region. These macroinvertebrates use macrophytes as a substrate for spawning and sites of protection against predators and feeding (Mormul et al, 2010), ingesting algae and detritus through water filtration (Gooderham and Tsyrlin, 2009).…”

Ostracod (Crustacea) colonization of a native and a non-native macrophyte species of Hydrocharitaceae in the Upper Paraná floodplain (Brazil): an experimental evaluation

“…Ostracod assemblages are among the most abundant groups associated with several species of macrophytes in Neotropical water bodies (Higuti et al, 2007(Higuti et al, , 2009aThomaz et al, 2008). These organisms are very common in most inland waters, where they abound in the benthic and periphytic animal assemblages, also in South America (Martens & Behen, 1994).…”

“…We used ostracods because (i) they are the second most abundant invertebrate group on macrophytes in this area (Oligochaeta being the first; Thomaz et al, 2008) and elsewhere (Martens et al, 2008), (ii) they are easy colonizers (many are free swimming and reproduce parthenogenetically, Martens et al, 2008), and are thus appropriate to our experimental approach, and (iii) they are one of the best known invertebrate groups in the Paraná floodplain, being relatively easily identified down to species level (see Higuti et al, 2007Higuti et al, , 2009a.…”

Five new species of Candoninae (Crustacea, Ostracoda) from the alluvial valley of the Upper Paraná River (Brazil, South America)

“…The collections made to study the ecology of the ostracods in the pleuston in the alluvial valley of the Upper Paraná River (Higuti et al 2007(Higuti et al , 2009b(Higuti et al , 2009cMormul et al 2010) also served for taxonomic revisions and several new species and genera of ostracods have meanwhile been described from lakes, river beds and channels of this floodplain (Higuti et al 2009a(Higuti et al , 2013Higuti & Martens 2012a, 2012b. Most of these new taxa belong to the family Cyprididae; only one paper thus far treated two species of Candonidae from this floodplain in detail (Higuti & Martens 2012b), describing a new genus and species, Candobrasilopsis rochai Higuti & Martens, 2012, and redescribing and generically transferring another species, Candobrasilopsis brasiliensis (Sars, 1901).…”

“…Close to 300 of these species have been described and reported from South America and more than 100 species are now known from Brazil (Martens & Behen 1994;Higuti et al 2009aHiguti et al , 2013Higuti & Martens 2012a, 2012b. Recent work on the alluvial valley of the Upper Paraná River (Higuti et al 2007(Higuti et al , 2009b(Higuti et al , 2009cMormul et al 2010) has contributed significantly to the general knowledge of ecology and biogeography of Brazilian freshwater ostracods, especially those occurring in the pleuston of floating plants. Floating plants such as species in the genera Eichhornia, Pistia and Salvinia are typical of South American (floodplain) lakes, and pleuston, the animal communities living in the root systems of such plants, are thus typical of such lakes.…”