Characterizing ecoregions in Argentinian Patagonia using extant continental ostracods.

A Patricia Pérez,Marta Alperin,Vera Markgraf,Corina Coviaga,Lorena Ramos,Antje Schwalb,Gabriela Cusminsky,Daniel Ariztegui,Finn Viehberg

doi:10.1590/0001-3765202020190459

Abstract

In order to characterize Patagonian (Argentina) ecoregions using non-marine ostracods, their associations in 69 environments were assessed. Twenty eight taxa were recorded, including 12 endemic of the Neotropical region. Our results indicate that Patagonian ostracods are mainly influenced by electrical conductivity (EC), altitude, pH, and temperature; and shows a correlation with Argentinian ecoregions. Assemblage I is composed of sites located at high altitude in the Andean Patagonian forest ecoregion. Host waters have low temperature, EC and pH, and support as representative species Cypris pubera, Eucypris virens, Bradleystrandesia fuscata, Tonacypris lutaria and Amphicypris nobilis. Assemblage II, related to mid-altitude environments in the Patagonian Steppe ecoregion, thrived in waters with moderate to high EC, and alkaline pH values. Dominant species includes Limnocythere rionegroensis, L. patagonica, E. virgata, Riocypris whatleyi, Riocypris sarsi, Newnhamia patagonica, Kapcypridopsis megapodus, Ilyocypris ramirezi and Penthesinelula incae. Assemblage III inhabited environments within Monte and Espinal ecoregions, situated in the eastern part of the study area at low altitude, EC moderate and temperate waters, supporting Heterocypris hyalinus, Amphicypris argentinensis, Sarscypridopsis aculeata, Cypridopsis vidua, Herpetocypris intermedia and Chlamidotheca incisa. Our results indicates that Argentinian Patagonia hosts a diverse ostracod fauna and highlights their capacity as proxies in ecological and palaeoenvironmental studies.

Highlights

Ostracods are bivalved microcrustaceans, which inhabit all types of aquatic environments (Mesquita-Joanes et al 2012, Martínez-García et al 2015)
Ilyocypris ramirezi was the most frequent species, recorded in 27 sites; followed by Heterocypris incongruens, Riocypris whatleyi and Eucypris virens that were present in 14-16 sites
Our research present the largest data set of extant non-marine ostracods in Patagonia, Argentina, analysing 69 aquatic environments including permanent, and ephemeral lakes, ponds and springs

Summary

Introduction

Ostracods are bivalved microcrustaceans, which inhabit all types of aquatic environments (Mesquita-Joanes et al 2012, Martínez-García et al 2015). Abiotic factors (salinity, water temperature, pH, water depth, substrate, oxygen content, water ionic composition, flow rate or permanence of a water body), biotic factors (submerged vegetation, food availability) and biologic interactions (predation, competence and parasitism) control the ostracod distribution and abundance (PalaciosFest et al 1994, Schwalb 2003, Mezquita et al 2005, Ruiz et al 2013, Coviaga et al 2018b). In this context, their sensitive ecological response to environmental changes favours the use of ostracods as bioindicators (Martínez-García et al 2015).

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