Erica E. Scheibler

Spatial and temporal patterns in the aquatic insect community of a high altitude Andean stream (Mendoza, Argentina)

Benthic invertebrate communities have been poorly studied in Andean streams apart from the Patagonian region. The primary objective of this work was to analyse the faunal composition at three different altitudes and to observe whether there were differences in aquatic insect community structure at spatial and temporal scales. Physicochemical variables were measured on a monthly basis. Sixteen families were found, the most frequent and abundant taxa being Massartellopsis (Ephemeroptera), Andesiops (Ephemeroptera), Metrichia neotropicalis (Trichoptera), Cailloma lucidula (Trichoptera), Austrelmis (Coleoptera), and the Chironomidae (Diptera). There was a change in benthic composition associated with land use and with the diminution of water quality from the headwaters to the mouth of the system. The middle reach was a transitional area where headwater species coexisted with species characteristic of the lower reach, with Austrelmis and the family Chironomidae being the most abundant elements.

Description of immature stages of Ectemnostega (Ectemnostega) quadrata (Signoret, 1885) (Heteroptera: Corixidae), with notes on ecological requirements of the species

The family Corixidae comprises a small group of true bugs that live in aquatic environments with abundant macrophytes. The genus Ectemnostega Enderlein includes two subgenera: Ectemnostega and Ectemnostegella, both known from South America, ranging from Ecuador to Tierra del Fuego. Ectemnostega (Ectemnostega) quadrata (Signoret, 1885) is distinguished by the widened posterior half of hemelytra, and the protibia of males prolonged over the base of pala. This species is distributed in Argentina and Chile along the Andes mountain range, from high altitudes in San Juan to sea level in Cabo Hornos, Tierra del Fuego. Adults and larvae were collected in association with Cladophora sp. and Chara sp. in northwestern Mendoza, from Los Horcones Lagoon (2891 m a.s.l.) and from ponds on southwestern slopes of Mendoza (Las Loicas locality, 1772 m a.s.l.). Larval stadia of Ectemnostega are described for the first time. Distributional and life habitats data of this species are provided.

The fate of endemic insects of the Andean region under the effect of global warming

Three independent but complementary lines of research have provided evidence for the recognition of refugia: paleontology, phylogeography and species distributional modelling (SDM). SDM assesses the ecological requirements of a species based on its known occurrences and enables its distribution to be projected on past climatological reconstructions. One advantage over the other two approaches is that it provides an explicit link to environment and geography, thereby enabling the analysis of a large number of taxa in the search for more general refugia patterns. We propose a methodology for using SDM to recognize biogeographical patterns of endemic insects from Southern South America. We built species distributional models for 59 insect species using Maxent. The species analyzed in the study have narrow niche breadth and were classified into four assemblages according to the ecoregion they inhabit. Models were built for the Late Pleistocene, Mid-Holocene and Present. Through the procedure developed for this study we used the models to recognize: Late Pleistocene refugia; areas with high species richness during all three periods; climatically constant areas (in situ refugia); consistent patterns among in situ refugia, Pleistocene refugia and current distribution of endemic species. We recognized two adjacent Pleistocene refugia with distinct climates; four in situ refugia, some of which are undergoing a process of fragmentation and retraction or enlargement. Interestingly, we found a congruent pattern among in situ refugia, Pleistocene refugia and endemic species. Our results seem to be consistent with the idea that long-term climate stability is known to have a key role in promoting persistence of biodiversity in an area. Our Pleistocene and in situ refugia are consistent with refugia identified in studies focusing on different taxa and applying other methodologies, showing that the method developed can be used to identify such areas and prove their importance for conservation.

The Patagonian Steppe biogeographic province: Andean region or South American transition zone?

America comprises three biogeographic regions: Nearctic, Neotropical and Andean. In between them, two transition zones (TZ) have been proposed: Mexican and South American. The biogeographic provinces belonging to a TZ have no predominance of biotic elements pertaining to each of its bordering regions. Regarding the Andean region, one of its provinces, the Patagonian Steppe, presents a mixture of different biogeographic elements, which are typical of transition zones. Because of this, we assessed whether the Patagonian Steppe belongs to the Andean region or whether it forms the southernmost part of the South American TZ. We gathered phylogenetic information from 177 taxa that inhabit the Patagonian Steppe and established to which biogeographic element they belong. We followed the criterion that an area can be considered as part of a region when at least 70% of its biota has the same origin, that is belongs to the same biogeographic element. In contrast, when the biota of an area presents a similar percentage of its different biogeographic elements, it could be considered as belonging to a transition zone. We found that the Patagonian Steppe presents a similar proportion of genera of Andean as well as neotropical origin. Therefore, we propose that this province should be included in the South American transition zone. Moreover, inclusion of the Patagonian Steppe as part of this TZ will make it the largest TZ of America, encompassing most of the arid lands of South America.

New species of Thinobius Kiesenwetter, 1844 (Coleoptera: Staphylinidae) from Argentina with ecological notes

Thinobius andinus sp. nov. from Argentina is described and illustrated, detailed information on its ecology is provided and a key to species of Thinobius from south‐western South America is given. This species was collected from high elevation stream areas of the Mendoza River watershed. It belongs to pollution‐sensitive species, and it was mainly found in clear, low‐salinity cold waters pertaining to high elevation streams with riparian vegetation. Lectotype is designated for Thinobius pulchripennis Bernhauer, 1923.

A New Species Of Pericompsus LeConte (Carabidae: Bembidiini, Tachyina) From Argentina

Abstract A new species of the genus Pericompsus Le Conte (Coleoptera: Carabidae: Bembidiini) is described from Catamarca province, Argentina. It is found along the borders of rivers and creeks in this arid region of western Argentina. The morphological characters of the new species place it within the subgenus Pericompsus (Pericompsus), and allow its recognition as a new species of the hirsutus species group. The discovery of this species extends the geographical range of the hirsutus group to the parallel 27° South. A description and illustration of the new species, together with a key to differentiate it from other hirsutus group species are provide.