Mariano Donato

nifH pyrosequencing reveals the potential for location‐specific soil chemistry to influence N2‐fixing community dynamics

A dataset of 87 020 nifH reads and 16 782 unique nifH protein sequences obtained over 2 years from four locations across a gradient of agricultural soil types in Argentina were analysed to provide a detailed and comprehensive picture of the diversity, abundance and responses of the N2 -fixing community in relation to differences in soil chemistry and agricultural practices. Phylogenetic analysis revealed an expected high proportion of Alphaproteobacteria, Betaproteobacteria and Deltaproteobacteria, mainly relatives to Bradyrhizobium and Methylosinus/Methylocystis, but a surprising paucity of Gammaproteobacteria. Analysis of variance and stepwise regression modelling suggested location and treatment-specific influences of soil type on diazotrophic community composition and organic carbon concentrations on nifH diversity. nifH gene abundance, determined by quantitative real-time polymerase chain reaction, was higher in agricultural soils than in non-agricultural soils, and was influenced by soil chemistry under intensive crop rotation but not under monoculture. At some locations, sustainable increased crop yields might be possible through the management of soil chemistry to improve the abundance and diversity of N2 -fixing bacteria.

Polypedilum parthenogeneticum (Diptera: Chironomidae): a new parthenogenetic species from Eryngium L. (Apiaceae) phytotelmata

All life stages of Polypedilum parthenogeneticum sp. n. are described and figured. The larva lives in the water held in the leaf axils of Eryngium pandanifolium Chamb and Schlecht (Apiaceae). The species is considered to be parthenogenetic as only females were obtained by rearing in the laboratory. Preliminary notes on the biology of P. parthenogeneticum are given.

Podonomus fastigians Brundin 1966 (Chironomidae: Podonominae): Redescription of the Adult Male and Female, the Pupa, and Description of the Larva

ABSTRACT: The larva of Podonomus fastigians is described for the first time, and the male and female adult and pupa are redescribed and illustrated. This is the first report of the non-biting midge P. fastigians in Argentina. Ecological remarks are included.

New record, geographic variation and redescription of Apedilum elachistus Townes (Diptera: Chironomidae: Chironominae)

Apedilum elachistus Townes 1945 is recorded from Argentina, representing the southernmost record of this species. Due to dissimilarities found between South and North American specimens a Principal Component Analysis and Minimum Spanning Tree were performed in order to determine if these differences reflect a geographic differentiation. The results show North–South variation in the number of acrostichal setae, number of dorsocentral setae, number of prealar setae, wing length, VR, length of thorax, and length of abdomen for males, and number of gonocoxite IX setae, length of thorax, number of temporal setae, length of palpomere III, wing length, BV2, length of notum, BV1, number of dorsocentral setae, length of palpomere IV, length of abdomen, VR, and length of palpomere V for females. Consequently, Apedilum elachistus is redescribed as larva, pupa, male, and female.

A taxonomic revision of the Patagonian species of the Dasyhelea mutabilis species group with a phylogenetic analysis of New World species (Diptera: Ceratopogonidae)

We provide a taxonomic revision of the Dasyhelea mutabilis species group inhabiting Patagonia, including diagnoses and identification key for both sexes of all species, descriptions and illustrations of seven new and three previously described species, and a discussion of phylogenetic relationships for each species. In addition, a cladistic analysis of the Neotropical and Nearctic species of the mutabilis group was performed using TNT version 1.1. It suggests that this group is not monophyletic, and this and other results are discussed within a phylogenetic framework. http://zoobank.org/urn:lsid:zoobank.org:pub:39D6AE31-36D1-4CBF-8C43-40050801ECAD

Monopelopia caraguata (Chironomidae: Tanypodinae: Pentaneurini) and Phytotelmatocladius delarosai (Chironomidae: Orthocladiinae): Two Phytotelmatous Chironomids Distributed from Florida to Argentina

Summary The geographic distribution of the 2 phytotelmatous chironomids Monopelopia caraguata and Phytotelmatocladius delarosai is found to extend southward into Argentina, and the occurrence of parthenogenesis in the latter species is corroborated under laboratory conditions.

A new species of Metriocnemus van der Wulp (Diptera: Chironomidae) with a tentative phylogeny of the genus

The male and female of the new species Metriocnemus puna sp. n from the Argentinean Puna are described and illustrated. A parsimony analysis including 24 well-described species of the genus plus the new species based on the adult male was conducted in order to access the phylogenetic position of the new species and to provide the first phylogenetic hypothesis for the genus.

Yungahelea, a new genus of predaceous midge from northwestern Argentina (Culicomorpha: Ceratopogonidae)

A new monotypic genus and species of predaceous midge from the southernmost area of the Argentinean Yungas, Yungahelea australis Spinelli and Ronderos, is described and illustrated from male and female adults. It belongs to a group containing the Ceratopogonini genera Parabezzia Malloch, Diaphanobezzia Ingram and Macfie, Spinellihelea Borkent, Grogan and Picado, Leptohelea Wirth and Blanton, and Fittkauhelea Wirth and Blanton. Phylogenetic interpretation indicates that Yungahelea is the sister group of Spinellihelea or the clade composed by Parabezzia and Diaphanobezzia.

Apedilum griseistriatum comb. nov., placement of Chironomus (Polypedilum) griseistriatum (Diptera, Chironomidae)

The study of the type material of Chironomus (Polypedilum) griseistriatum Edwards, 1931 described from Patagonia lead us to formally transfer the species to Apedilum Townes, 1945 as a new combination, and a reared specimen allows us to describe its pupa. Based on several larvae belonging to Apedilum collected in the proximity of the localities in which the adults and pupae were found, we tentatively describe the larval stage. Subfossil larval head capsules of the same species were found in Laguna Stibnite at 46°S in Chile dated to about 2,500 years ago and in Puerto Blest, Lago Nahuel Huapi at 41°S in Argentina dated about 2,000 years ago. We discuss the habitat of the species based on both modern and subfossil material. Identification keys to male adult, pupae and fourth instar larvae are also provided.

Description of a new species of the genus Onconeura Andersen et Sæther (Diptera: Chironomidae) from Argentina with a cladistic analysis of the genus

The male, female and immature stages of the new species Onconeura analiae from Argentina are described and figured. A parsimony analysis including the seven known species of the genus plus the new species, using a combined data set of continuous and qualitative characters, was conducted in order to assess the phylogenetic position of the new species and to give for the first time a phylogenetic hypothesis of the genus.