Ischnura ultima Ris , 1908 ( Odonata : Coenagrionidae ) : New records from southern South America

Southern South America has been defined as the area south to 30° S and the Andean highlands North of this latitude; it encompasses large areas of Argentina, Chile, Uruguay and southern Brazil (Crisci et al. 1991). From a biogeographical point of view this area has a Neotropical and Subantartic component. From an odonatological point of view, the Subantarctic component is characterized by high diversity at a family level, but a low species richness and a high degree of endemicity, whereas the Neotropical one is represented by almost 250 species, with only a few of them exclusive to Argentina and Chile. Taking into account the odonate species exclusive to Argentina, von Ellenrieder and Muzón (2008) proposed five areas of endemism. One of these areas is supported by the presence of Andinagrion peterseni (Ris, 1908) and Ischnura ultima (Coenagrionidae), Rhionaeschna haarupi (Ris, 1908) and Rhionaeschna pallipes (Fraser, 1947) (Aeshnidae) and Progomphus joergenseni Ris, 1908 (Gomphidae) (Figure 1). All the five mentioned species inhabit streams with moderate energy in hill landscapes or associated small ponds. This area extends from the north of Argentina along the eastern slope of the Andes, hills and plateaus systems to northern Patagonia (approximately 42o S) where it turns to the East up to the southern hills of Buenos Aires Province (Ventania and Tandilia systems) (Figure 1). This large and heterogeneous area which is characterized by arid or semi arid conditions crosses several biogeographical provinces (i.e., Prepuna, Monte, Patagonian, Espinal and Pampean) and integrates several biodiversity hotspots (e.g., Pampa de Achala, Payunia and Somuncura) (Roig Juñent and Debandi 2004; Muzón et al. 2005). The cosmopolitan genus Ischnura Charpentier is represented in southern South America by three described and one undescribed species: I. capreolus (Hagen, 1861), I. fluviatilis Selys, 1876 and I. ultima (von Ellenrieder and Muzón 2008). The first two species have large distribution areas in the Neotropical region, being common inhabitants of still waters on the northern half of Argentina. On the other hand, I. ultima has been recorded for the eastern slope of the Andes (Argentina), from Salta and Jujuy Abstract: Ischnura ultima Ris, 1908 is recorded for the first time from Buenos Aires Province, Argentina, 750 km southeast from the southernmost previous known localities (Córdoba Province). This finding supports a stronger biogeographical relationship between the southern hills of Buenos Aires (surrounded by the Pampas lowlands) and the Monte province. In addition, this record supports the odonate endemic areas scheme previously proposed for Argentina. Instituto de Limnología “Dr. R.A. Ringuelet” (CONICET-CCT La Plata), C.C. 712. 1900. La Plata, Argentina. * Corresponding author. E-mail: muzon@ilpla.edu.ar Javier Muzón *, Alejandro del Palacio and Lía Ramos Ischnura ultima Ris, 1908 (Odonata: Coenagrionidae): New records from southern South America

Southern South America has been defined as the area south to 30° S and the Andean highlands North of this latitude; it encompasses large areas of Argentina, Chile, Uruguay and southern Brazil (Crisci et al. 1991).From a biogeographical point of view this area has a Neotropical and Subantartic component.From an odonatological point of view, the Subantarctic component is characterized by high diversity at a family level, but a low species richness and a high degree of endemicity, whereas the Neotropical one is represented by almost 250 species, with only a few of them exclusive to Argentina and Chile.
Taking into account the odonate species exclusive to Argentina, von Ellenrieder and Muzón (2008) proposed five areas of endemism.One of these areas is supported by the presence of Andinagrion peterseni (Ris, 1908) and Ischnura ultima (Coenagrionidae), Rhionaeschna haarupi (Ris, 1908) and Rhionaeschna pallipes (Fraser, 1947) (Aeshnidae) and Progomphus joergenseni Ris, 1908 (Gomphidae) (Figure 1).All the five mentioned species inhabit streams with moderate energy in hill landscapes or associated small ponds.This area extends from the north of Argentina along the eastern slope of the Andes, hills and plateaus systems to northern Patagonia (approximately 42º S) where it turns to the East up to the southern hills of Buenos Aires Province (Ventania and Tandilia systems) (Figure 1).This large and heterogeneous area which is characterized by arid or semi arid conditions crosses several biogeographical provinces (i.e., Prepuna, Monte, Patagonian, Espinal and Pampean) and integrates several biodiversity hotspots (e.g., Pampa de Achala, Payunia and Somuncura) (Roig Juñent and Debandi 2004;Muzón et al. 2005).
The cosmopolitan genus Ischnura Charpentier is represented in southern South America by three described and one undescribed species: I. capreolus (Hagen, 1861), I. fluviatilis Selys, 1876 andI. ultima (von Ellenrieder andMuzón 2008).The first two species have large distribution areas in the Neotropical region, being common inhabitants of still waters on the northern half of Argentina.On the other hand, I. ultima has been recorded for the eastern slope of the Andes (Argentina), from Salta and Jujuy Abstract: Ischnura ultima Ris, 1908 is recorded for the first time from Buenos Aires Province, Argentina, 750 km southeast from the southernmost previous known localities (Córdoba Province).This finding supports a stronger biogeographical relationship between the southern hills of Buenos Aires (surrounded by the Pampas lowlands) and the Monte province.In addition, this record supports the odonate endemic areas scheme previously proposed for Argentina.
The new findings in Salta, Tucumán, Córdoba and Mendoza Provinces are consistent with the previously known distribution area of this species.Nevertheless, the record from Sierra de la Ventana represents the first one from Buenos Aires Province, about 750 km southeast from the nearest known localities (Córdoba Province).This new record supports the endemic area proposed by von Ellenrieder and Muzón (2008) and suggests a closer biogeographical relationship between the southern hills of Buenos Aires and the Monte, than between the former and the surrounding lowlands (the Pampas).On the other hand, and considering Uspallata (Mendoza province, Argentina) and Llaillay (Valparaiso region, Chile) records, which are separated by the highest portion of the Andes, it is suggested that Ischnura ultima could have a larger distribution area in Chile.

Figure 1 .
Figure 1.Political division of Argentina and Chile showing distribution of Ischnura ultima overlapping endemism proposed by von Ellenrieder and Muzón (2008).