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

J Higuti,Rl Pinto,Lcg Vieira,Lfm Velho,Fa Lansac-Tôha,K Martens

doi:10.1590/s1519-69842009000200004

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.

Highlights

The upper Paraná River floodplain has been the focus of intense limnological and ecological research over recent decades
Darwinulidae comprise less than 5% of the specific diversity of freshwater ostracod fauna (Martens, 1998)
The stretch of the floodplain studied here is located between the coordinates 22° 26’, 22° 56’ S and 53° 10’, 53° 40’ W (Figure 1)

Summary

Introduction

The upper Paraná River floodplain has been the focus of intense limnological and ecological research over recent decades. Most studies have been carried out by researchers of the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia) from the Universidade Estadual de Maringá, and focused on ecological aspects of several floodplain environments (Thomaz et al, 2004, among others). J. Biol., 69(2): 253-262, 2009 vertebrate diversity in this area (Velho et al, 2001; Higuti and Takeda, 2002; Lansac-Tôha et al, 2002), there are no published records about the ecology and distribution of ostracods in the alluvial valley of the upper Paraná River. In the last decade, this family has received much attention from researchers, due to its recognition as a possible ancient asexual group (Butlin and Griffiths, 1993). Several biological and ecological (Van Doninck et al, 2003a, b), molecular (Schön et al, 2003; Martens et al, 2005), and taxonomical studies (Martens et al, 1997; Martens and Rossetti, 2002; Rossetti and Martens, 1996; 1998) have been conducted

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Conclusion