Search

Traditionally, South American aquatic insects have been divided into cold and warm adapted forms. Cold-adapted forms inhabit freshwater systems from higher latitudes, or higher altitudes even around the Equator. Warm-adapted groups are defined as those found in lower latitudes and altitudes. This work aims to answer the questions: Are mayfly assemblages geographically segregated according to geographical (latitude) and topographical (altitude) surrogates of temperature? If so, where is this transition located? Location: South America. Methods: We compiled a data set about the relative incidence of 52 mayfly genera in 326 sampled communities. They span from 0 to 4,320 m and from 47.77° S to 5.74° N latitude. By virtue of the compositional nature of the data set, we applied the statistical procedures behind the Aitchison compositional data analysis. We delimited groups of assemblages based on their Aitchison distances and projected the data points onto a biplot obtained through Principal Component Analysis adjusted to compositions (Aitchison PCA). Results: A strong correspondence among biological and geographical information was detected, with mayfly assemblages clearly segregated in space. Andesiops and Meridialaris are typical cold-adapted forms; Baetodes, Leptohyphes and Thraulodes represent the warm group. Thermal groups can be separated by a curved line of altitude in function of latitude expressed in terms of a superellipse arc. Main conclusions: The classical ecological bipartition of mayflies into warm and cold freshwater groups is formalized quantitatively. The dividing line between warm and cold assemblages levels off at high altitudes (c. 3,300 m) around the Equator and falls to sea level at southern latitudes. The community bipartition line is useful for tracking global change through records of altitudinal displacement below and above of the warm/cold line of involved ecological groups. Fil: Dos Santos, Daniel A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Molineri, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Nieto Peñalver, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Zúñiga, María Angélica. Universidad del Valle; Colombia Fil: Emmerich, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Fierro, Pablo. Universidad de Concepción; Chile Fil: Pessacq, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina. Centro de Investigaciones Esquel de Montaña y Estepa Patagónicas (ciemep) Esquel; Argentina Fil: Rios-Touma, Blanca. Universidad de Las Americas; Ecuador Fil: Márquez, Javier Andrés. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Gomez, Graciela Cecilia. Universidad Nacional de Jujuy. Instituto de Biología de la Altura; Argentina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina Fil: Salles, Frederico F.. Universidade Federal do Espírito Santo; Brasil Fil: Encalada, Andrea C.. Universidad San Francisco de Quito; Ecuador Fil: Principe, Romina Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina Fil: Gomez, Graciela Cecilia. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; Argentina Fil: Valdovinos Zarges, Claudio. Department Of Aquatic Systems, Faculty Of Environmental; Chile Fil: Dominguez, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina

Aim: To study the relationships between Uruguay and neighbouring geographical areas based on distributions of Ephemeroptera species (mayflies: an ancient order of aquatic insects). We wanted to evaluate whether Uruguay more closely represents (1) the southern limit of the tropical (Paranense and Amazonian) fauna or (2) the northern limit of the temperate (Pampean-Bonaerense) fauna. Location: South America with an emphasis on Uruguay. Methods: We compiled more than 5000 collection records of mayfly species throughout South America and evaluated these using current taxonomy and geographical validity. We used the Network Analysis Method (NAM) on these data to identify units of co-occurrence (UCs: mutually exclusive groups of co-distributed species, with each group connected through strong links of sympatry and disconnected from the others). We focused solely on those UCs that included Uruguay in their spatial ranges and used these to infer the vicinity relationships. Results: We recovered four UCs consisting of many species that link Uruguay with tropical areas of Brazil and NE Argentina. These groups followed a geographically nested pattern. The results contradict the previously held view that the Uruguayan fauna holds strong affinities to that of temperate grasslands that lie to the south in central oriental Argentina (i.e. the currently accepted concept of Pampas). A comparison of the genera known from Uruguay and Buenos Aires Province further reinforces the distinction between Uruguay and temperate areas to the south. Main conclusions: The hypothesis that Uruguay represents the southern limit of tropical affinities is strongly supported by mayfly distributions, indicating that a reappraisal of the Pampas as a cohesive biogeographical province is needed. We suggest that Uruguay and Buenos Aires should belong to different provinces, the former aligned with tropical provinces and the latter aligned with more temperate areas. Fil: Dos Santos, Daniel Andrés. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán; Argentina Fil: Emmerich, Daniel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán; Argentina Fil: Molineri, Carlos. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán; Argentina Fil: Nieto, Carolina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán; Argentina Fil: Dominguez, Eduardo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán; Argentina

To analyse speciation within the large Neotropical genus Campsurus Eaton, we examined apparent subgroupings by morphological methods using discrete and continuous character states. In this report, the albifilum group is redefined based on redescription of male imagos of Campsurus albifilum from the holotype and fresh material and from four closely related new species: Campsurus yavarin.sp. and C. fuliginatusn.sp. described from male imagos; and C. homaulosn.sp. and C. gracilipenisn.sp. described from imagos of both sexes. An illustrated key to distinguish the male adults of all species in the albifilum group is included. A phylogeny of the group is proposed based on a matrix of seven continuous and 12 discrete characters analysed under implied weights, and includes additional species representing all known or previously proposed groups. This demonstrates the practical application of methods using continuous characters to give additional resolution and support to the phylogeny. The monophyly of the major and the albifilum groups is confirmed. Based on these results, a biogeographical analysis is conducted (spatial analysis of vicariance) based on distributional records for each species. Two main vicariant events are found: (i) a west–east separation in tropical-subtropical South American lowlands, followed by (ii) a north–south separation of the Amazonas and Parana regions. Sympatric speciation seems common: most sister species pairs are co-distributed, and show nonoverlapping ranges in body size.

A cladistic analysis of the South American members of the family Leptohyphidae is presented. A matrix of 73 taxa and 124 morphological characters was analyzed under two distinct weighting criteria (implied weighting, which weights characters as a whole, and self-weighted optimization, which differentially weights character state transformations). To assess the monophyly of the Leptohyphidae, some representatives of Ephemerellidae, Ephemerythidae, Machadorythidae, Teloganodidae, Tricorythidae, Coryphoridae, and Melanemerellidae, were also included. Trees were rooted in Ephemerellidae. Conspicuous differences in consensus topology occur when transformation costs among character states are weighted (including asymmetries). The differences in the assessments of character reliability in the two weighting criteria used are discussed. In many cases, self weighting, in allowing for asymmetries in transformation costs, considered many of the character state transformations as more reliable (=informative) than implied weights (which needlessly down-weighted the whole character). The results confirm the monophyly of Leptohyphidae and support its sister group relationship with Coryphoridae. Higher classification of the Ephemerelloidea is briefly discussed. Shortest trees do not support the recently proposed division of Leptohyphidae in two subfamilies. Fil: Molineri, Carlos. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina