Abstract A new coenagrionid genus, Negragrion, is described for N. sagma sp.n. found in Argentina and Brazil (Holotype and allotype, pair in tandem. Argentina: Corrientes: Santo Tomé, arroyo Ita Cuá sobre RP 94, 28°26’48.30”S 56°00’33.11”W, 24.ii.2003, Muzón & Pessacq coll., MLP). The new genus is characterized by the shape of male cerci (decumbent from base; saddle-shaped; in lateral view with an acute apophysis directed dorsally located at 0.3 from base). The presence of a vulvar spine on S8 of females places this genus within Ischnurinae. A cladistics analysis using morphological data was carried out to determine its phylogenetic position. Negragrion gen.n. is recovered within the clade 4 as the sister group of the clade (Acanthallagma Acanthagrion (Oxyagrion, Fluminagrion)).

Abstract The American genus Argia, with more than 100 species described, is the most speciose genus of Odonata in the world. In this contribution, the final stadium larva of Argia serva, the southernmost distributed species of Argia, is described and diagnosed based on reared material from Martín García island, Buenos Aires, Argentina. The larva of this species can be easily separated from the other Argentinean Argia by the following combination of characters: sternum of S8 covered with spines (bare in A. translata); antennal segment 3 longer than 1+2 (equal to or shorter than 1+2 in A. joergenseni and A. jujuya); palpal setae absent (present in A. croceipennis). A key to the known larvae of Argia of the Southern Cone is provided.

Abstract Acanthagrion marinae sp. nov. (Holotype male: BRASIL, Mato Grosso do Sul, Campo Grande, UFMS, 20°29’56.26’’S - 54°36’48.43’’W, 547m, leg. M.E. Rodrigues, 03.ii.2015, collection code: VZYG437, MLP) is described and illustrated on the basis of 15 males. The new species belongs to the apicale species group by having horns on S10 and sclerotized hooks on tip of distal segment of the genital ligula. It can be easily distinguished from other species of the group by a combination of characters of the genital ligulae (presence of setae on segment two; absence of setae at flexure; distal lateral lobes of segment three absent). Notes on habitat and a modification of previous keys for the species of the apicale group are provided.

A preliminary inventory of the Odonata from Iberá Wetlands and their area of influence (Corrientes, Argentina) is presented. Different kinds of environments were surveyed in seven localities. Seventy five species grouped in 33 genera and seven families were registered, from which three genera and 10 species are new records for the country. The localities belonging to the Iberá Wetland system show low endemicity and a high faunistic relationship with the Paraná basin.

Se presenta un inventario preliminar de los Odonata de los Esteros del Iberá, así como su área de influencia (Corrientes, Argentina). Distintos tipos de ambientes fueron muestreados en siete localidades. Se registraron setenta y cinco especies agrupadas en 33 géneros y siete familias, de las cuales tres géneros y 10 especies son nuevos registros para el país. Las localidades que pertenecen al sistema de Esteros del Iberá, muestran bajos niveles de endemismo y una similitud faunística elevada con la cuenca del Paraná.

The Neotropical genus Acanthagrion Selys (Odonata: Coenagrionidae) is composed by 41 species, eight of which have the last instar larva described. In this contribution the last instar larva of Acanthagrion aepiolum Tennessen is described based on material collected in Corrientes (Argentina) and it is compared with the larvae known for Argentina.

El género neotropical Acanthagrion Selys (Odonata: Coenagrionidae) está integrado por 41 especies. Hasta el momento sólo se ha descripto el último estadio larval de ocho de ellas. En este trabajo, se describe el último estadio larval de Acanthagrion aepiolum Tennessen; sobre la base de cuatro especímenes recolectados en Corrientes (Argentina) y se compara con las demás larvas conocidas para la Argentina.

The genus Micrathyria Kirby (Odonata: Libellulidae) is composed by 46 species, 16 of which are known from Argentina. In this contribution we describe the last instar larva of Micrathyria ungulata Förster based on material collected in Maguire stream (Buenos Aires, Argentina) and we compare it with the larvae of the genus recorded in Argentina.

El género Micrathyria Kirby (Odonata: Libellulidae) está integrado por 46 especies, 16 de las cuales se han citado para Argentina. En esta contribución se describe el último estadio larval de Micrathyria ungulata Förster , sobre la base de un espécimen coleccionado en el arroyo Maguire (Buenos Aires, Argentina), y se lo compara con las larvas del género presentes en Argentina.