The genus Aphis (Hemiptera, Aphididae) living on Asteraceae species in southern South America: Argentina and Chile, with five new species.

In the whole of Argentina and Chile, southern South America in this paper, 20 species of the genus Aphis hosted in species of Asteraceae were known; eleven of them are native South American, and those introduced are mostly polyphagous and widespread. The Chilean regions and the Argentine provinces in which each one of them is known, as well as the host plants on which it has been recorded, are listed. New data of 15 of them are presented, with several first records in different Argentine provinces or hosted on diverse plants: The knowledge of A. conspicua and A. fuentesi, which were recently described living on species of Baccharis, is improved from specimens respectively collected on Senecio and Gutierrezia. A. rogerblackmani Nieto Nafra, Ortego Mier Durante sp. n. is described from apterous and alate viviparous females, oviparous females and males collected on Baccharis in Argentina. Other four species are described from apterous and alate viviparae: A. gutierreziae Ortego, Mier Durante Nieto Nafra sp. n., collected on species of Gutierrezia in Argentina, A. hyalis Mier Durante, Nieto Nafra Ortego sp. n., collected on Hyalis argentea in Argentina, A. pulverea Nieto Nafra, Moreno-Gonzlez Ortego sp. n., collected on species of Senecio in Chile and Argentina, and A. sanrafaelina Ortego, Mier Durante Nieto Nafra sp. n., collected on Tagetes mendocina, Thymophylla pentachaeta and Pectis odorata in Argentina. The intraspecific diversity of Aphis pulverea has been analysed by a principal component analysis followed by hierarchical clustering of principal components. An identification key to viviparous females of the species of Aphis hosted in Asteraceae and known in southern South America is presented.

Blanchardaphis poikila syn. n. to B. capitophoroides and Blanchardaphis syn. n. to Lambersius (Hemiptera, Aphididae, Aphidinae, Macrosiphini, Uroleucon).

Blanchardaphis was erected for two Argentinian species of aphids very similar to Uroleucon, but distinguished by several characters. Here, we examined morphology and DNA sequences of Blanchardaphis specimens from Argentina and Chile. We further conducted a phylogenetic analysis to determine the relationship of Blanchardaphis to Uroleucon. We found minor morphological and genetic differences between Blanchardaphis samples based on geography, which appear to be population-level variation. On the basis of current evidence, we conclude that B. poikila (Ortego, Nieto Nafra Mier Durante, 1997) is synonymous with B. capitophoroides (Blanchard, 1942), and that Blanchardaphis Ortego, Nieto Nafra Mier Durante, 1998 is synonymous with Lambersius Olive, 1965 (subgenus of Uroleucon) sensu Nieto Nafra et al. 2007 or alternatively with the subgenus Uroleucon.

Aphis mirabilis sp. n. (Hemiptera, Aphididae, Aphidina), a South American species resembling A. craccivora, and further data on A. tropaeoli.

We examined 1367 apterous viviparae from 151 samples to study Aphis craccivora, A. tropaeoli and a third, possibly new species in Argentina, resembling both. Principal component analysis (PCA), followed by hierarchical clustering of principal components (HCPC), revealed clusters based on 33 morphological characters of 206 selected specimens. The delimitation of possible taxonomic entities was assessed by logistic regression. PCA confirmed that A. tropaeoli is a valid species. HCPC revealed the existence of a new species distinct from A. craccivora. Recently published data on the variability of A. craccivora, mainly regarding Asian populations, are presented and discussed; the general appearance of the sexuals of this species is also presented. The new species is described with the name Aphis mirabilis Nieto Nafra and Ortego sp. n., based on apterous and alate viviparae, oviparae, and males collected in Mendoza and Neuqun (Argentina) on Adesmia volckmannii (Fabaceae), Atriplex nummularia and At. lampa (Amaranthaceae), Bougainvillea spinosa (Nyctaginaceae), and Robinia pseudoacacia (Fabaceae). This new species has also been collected on plants of another 18 species from 8 additional families, although these specimens are not included in the type series. Features to distinguish A. mirabilis Nieto Nafra and Ortego sp. n. from A. craccivora are presented together with a logistic regression model. The males of A. tropaeoli are described. The list of host plants of A. craccivora in Argentina is updated.

A further contribution to the knowledge of Uroleucon species (Hemiptera, Aphididae) living on Adesmia (Fabaceae) in southern South America, with description of a new species from Chile.

Uroleucon (Hemiptera, Aphididae, Macrosiphini) is a highly diverse and widely distributed genus. Most of its species are hosted by plants of the Asteraceae or Campanulaceae, but three species from the southern end of South America have specialized to live on plants of the genus Adesmia (Fabaceae). New morphological and chorological data are provided for U. adesmiae Mier Durante and Ortego and U. naheulhuapense Nieto Nafría von Dohlen, with a description of the alate viviparous female of the latter species. U. australe Nieto Nafría Mier Durante, sp. n. is described from apterous viviparous females, oviparous females and males from four localities in the Chilean regions of Aysén and Magallanes; it is very close to U. nahuelhuapense, both morphologically and genetically. Contrary to what is typical for aphids, the males of U. australe have a greater number of distinguishing characters than are found in viviparous females. A modification of the identification key to the apterous viviparous females of the known Uroleucon species in South America by Nieto Nafría et al. (2019) is presented.

Three new species of the genus Neuquenaphis (Hemiptera, Aphididae, Spicaphidinae) from southernmost South America.

Three new species of Neuquenaphis Blanchard are described from aphids collected in southernmost South America on several species of Nothofagus, southern beeches: Neuquenaphis blackmani Nieto Nafría and Brown, sp. n. from apterous and alate viviparous females and alatoid nymphs collected on Nothofagus dombeyi in Los Lagos and Los Ríos regions (Chile) and on Nothofagus nitida in Los Ríos region, Neuquenaphis aurata Mier Durante and von Dohlen, sp. n. from apterous and alate viviparous females collected on Nothofagus betuloides in Magallanes region (Chile) and Tierra del Fuego province (Argentina), and Neuquenaphis ramireziNieto Nafría and Ortego, sp. n. from apterous viviparous females collected on Nothofagus pumilio and N. antarctica in Tierra del Fuego province (Argentina) and La Araucanía, Aysén and Magallanes regions (Chile). Sequences of the mitochondrial COI "barcode" region and the tRNAleu-COII locus support the distinction of these new species from described Neuquenaphis species. Morphological characteristics that differentiate the new species from already described species of the genus are discussed. Partial identification keys for known apterous and alate viviparous females of Neuquenaphis species are presented on the basis of those established by Quednau (2010).

Aphis (Hemiptera, Aphididae) species living on Baccharis (Asteraceae) in southern South America, with description of three new species.

Aphid specimens belonging to the genus Aphis (Hemiptera, Aphididae, Aphidinae) collected on species of Baccharis (Asteraceae) in localities of Argentina and Chile, preserved in the Natural History Museum in London and in the Universidad de León collections, have been studied. They belong to six species: Aphis craccivora, Aphis gossypii and Aphis spiraecola, which are widely-distributed and polyphagous, and the new species: Aphis ingeborgae Nieto Nafría and Brown sp. n., Aphis conspicua Nieto Nafría and Mier Durante sp. n. and Aphis fuentesi Nieto Nafría and Ortego sp. n. which are here described from apterous and alate viviparous females, and also from oviparous females and males in the case of Aphis fuentesi. These six species plus the native and monophagous A. coridifoliae are those known in southern South America living on plants of Baccharis. Diagnostic features of new species and an identification key for apterous viviparous females of these seven species are presented.

The species of Uroleucon (Hemiptera: Aphididae) living on Adesmia (Fabaceae) in Argentina, with the description of a new species.

Uroleucon Mordvilko is the largest genus in the Macrosiphini (Hemiptera, Aphididae) and most of its species live on species of Asteraceae. Uroleucon nahuelhuapense Nieto Nafría von Dohlen sp. n. is described from apterous viviparous females collected on Adesmia boronioides (Fabaceae) in a locality of Neuquén province (Argentina). The morphological characters and the sequence of the tRNAleu-COII mitochondrial locus support the inclusion of the new species in the genus Uroleucon. Apterous viviparous females of Uroleucon adesmiae Mier Durante Ortego collected in two Argentinean localities have also been studied and ranges of several quantitative features have been modified. The identification key for the Uroleucon species known in South America by Nieto Nafría et al. (2007) has been modified to include the new species.

EF-1α DNA Sequences Indicate Multiple Origins of Introduced Populations of Essigella californica (Hemiptera: Aphididae).

Aphids in the pine-feeding Nearctic genus Essigella (Sternorrhyncha, Aphididae, Lachninae) have been introduced in Europe, North Africa, Oceania, and South America. Mitochondrial, nuclear, and endosymbiont DNA sequences of 12 introduced populations from three continents confirm they all belong to Essigella californica (Essig, 1909). Intron sequence variation of the nuclear gene EF-1α has revealed the existence of four distinct groups. Group I gathers one population from China, where the species is newly reported, and several from Europe (France and Italy); Group II is represented by one population from Argentina; Group III includes two populations from Southern Australia with one from New Zealand; and Group IV corresponds to five populations from Eastern and South-Eastern Australia. These results indicate that introduced populations of E. californica have at least four source populations. They also show that intron variation of EF-1α can be a method to discriminate populations of asexually reproducing aphids.

Aphis species (Hemiptera, Aphididae) living on Mulinum (Apiaceae) in South America, with a description of a new species.

Aphis species living on the South American native genus Mulinum are studied. Aphis vurilocensis Nieto Nafría, Brown and López Ciruelos, sp. n. is described from apterous viviparous females. Alate viviparous females, oviparous females and winged males of Aphis roberti are described. Knowledge of intraspecific variability of apterous viviparous females of A. martinezi, A. paravanoi and A. roberti is developed. An identification key of apterous viviparous females of Aphis species living on Mulinum is presented.

Three new South American species of genus Aphis (Hemiptera: Aphididae) living on species of Euphorbia (Euphorbiaceae).

Three species of Aphis living on species of Euphorbia in Argentina and Chile are described: Aphis tehuelchis Nieto Nafría & López Ciruelos, sp. n., from viviparous females collected in the Argentinean provinces of Santa Cruz and Neuquén, Aphis maulensis Mier Durante & García-Tejero, sp. n., from viviparous females collected in the Chilean Region VII, and Aphis eucollinae López Ciruelos & Ortego, sp. n., from viviparous females, oviparous females and males collected in the Argentinean province of Mendoza. These new species may be distinguished from each other, besides other features, by the abdominal marginal tubercles: in A. tehuelchis these are present on segments 1 and 7 and on several of segments 2 to 6, in A. maulensis they are on segment 1 and on several segments 2 to 6, but lacking on segment 7, and in A. eucollinae they are only on segments 1 and 7. Differences between the new species and those currently known living on Euphorbia around the world are presented.