Impact of rainbow trout on aquatic invertebrate communities in subtropical mountain streams of northwest Argentina

Este estudio se realizó para evaluar el efecto de la introducción de trucha arcoiris en las comunidades de invertebrados bentónicos, estratificados en epibentos e infauna. Se exploran principalmente dos cuestiones: 1) si la estructura de la comunidad bentónica es diferente en el arroyo con truchas respecto a los arroyos con peces autóctonos; y 2) si la presencia de truchas afecta diferencialmente al epibentos y a la infauna. Se tomaron muestras del epibentos, infauna, deriva y contenido estomacal de peces en cuatro fechas y tres sitios para estudiar el impacto de la trucha arcoiris (Oncorhynchus mykiss) sobre la fauna de invertebrados acuáticos. Se registró solo una especie de pez nativo, el siluriforme Trichomycterus corduvense. Ambas especies de peces fueron encontradas siempre en alopatría. La estructura de la comunidad en el sitio con truchas resultó diferente de la de los otros arroyos con una menor abundancia de invertebrados epibentónicos grandes y activos (e.g., Perlidae, Gripopterygidae, Hydropsychidae, Leptoceridae, adultos de Elmidae) y una mayor importancia de organismos infaunales (Chironomidae, Oligochaeta). Los índices de diversidad presentaron valores altos y bajos alternados en el tiempo, y este patrón oscilante resultó opuesto en el sitio con truchas al de los sitios sin trucha.The present study was conducted to assess the effect of rainbow trout introduction on benthic invertebrate communities, stratified as epibenthos and infauna. Two main questions are explored: 1) do the trout-invaded streams show a different community structure than the streams with autochthonous fish?, and 2) does the presence of trout affect differentially the epibenthos and the infauna? Epibenthic and infaunal samples, drift samples and fish stomach content were sampled four times from three stations to assess the impact of rainbow trout (Oncorhynchus mykiss) on the invertebrate aquatic fauna. Only one species of native fish was recorded in the studied sites, the siluriform Trichomycterus corduvense. Both fish species were found always in allopatry. The trout-invaded site has a different community structure than the other streams with a much lower abundance of large and active epibenthic taxa (e.g., Perlidae, Gripopterygidae, Hydropsychidae, Leptoceridae, Elmidae adults) and an increase in the importance of infaunal organisms (Chironomidae, Oligochaeta). Diversity indices showed alternating and opposite high and low values along time in trout-free and invaded sites

A cladistic revision of Tortopus Needham & Murphy with description of the new genus Tortopsis (Ephemeroptera: Polymitarcyidae)

Se realiza un análisis filogenético y revisión taxonómica de las 12 especies previamente ubicadas en Tortopus, junto con 3 nuevas especies descriptas aquí. Sobre la base de caracteres sinapomórficos de ninfas y adultos de ambos sexos, Tortopus es restringido a T. igaranus Needham & Murphy, T. circumfluus Ulmer, T. harrisi Traver, T. zottai (Navás), T. bellus Lugo-Ortiz & McCafferty, y T. arenales sp. nov., y definido por: receptores de parastilo en hembras con largos surcos anteriores a los bolsillos; penes deprimidos; esterno abdominal IX del macho separado en dos porciones laterales por un surco mediano; mesosternum con protuberancias furcasternales contiguas sólo en la base; y ninfas con dos tubérculos subapicales en los colmillos mandibulares. El nuevo género Tortopsis es descripto para T. bruchianus (Navás), T. limoncocha sp. nov., T. obscuripennis (Domínguez), T. parishi (Banks), T. primus (McDunnough), T. puella (Pictet), T. sarae (Domínguez), T. spatula sp. nov., y T. unguiculatus (Ulmer). Tortopsis se caracteriza por: sector R en ala anterior femenina sin venas adicionales entre R2 e IR; receptores de parastilo en hembras con forma de C o V, con bolsillos abriéndose hacia la línea media; gonoporo masculino asociado a una estructura en forma de garra; penes separados desde la base; parastilos con una longitud cinco veces mayor a la de los pedestales; parastilos curvados en vista lateral; ninfas con un solo tubérculo subapical en los colmillos mandibulares. El estudio del material tipo de todas las especies disponibles permitió la inclusión de diagnosis comparativas, con las figuras y redescripciones necesarias. El macho imago de la especie tipo de Tortopus (T. igaranus Needham & Murphy) es descripto por primera vez, así como las hembras adultas de Tortopus bellus Lugo-Ortiz & McCafferty y T. harrisi Traver. Se describen tres nuevas especies neotropicales sobre la base de adultos de ambos sexos: Tortopus arenales y Tortopsis limoncocha de Ecuador, y Tortopsis spatula de Colombia. Se ofrecen claves para separar los adultos y ninfas de los géneros de Polymitarcyidae y para los machos y hembras de las especies de Tortopus y Tortopsis, así como dibujos, fotos y fotografías de microscopía electrónica para las estructuras consideradas de interés sistemático.The 12 species previously placed in Tortopus together with 3 species newly described here, are revised and included in a phylogenetic analysis. Based on synapomorphic characters on the nymphs and adults of both sexes, Tortopus is restricted to T. igaranus Needham & Murphy, T. circumfluus Ulmer, T. harrisi Traver, T. zottai (Navás), T. bellus Lugo-Ortiz & McCafferty, and T. arenales sp. nov., and the genus is defined by: female parastyli receptors with long furrows anterior to sockets; penes entirely flattened; male ninth abdominal sternum almost separated in two portions by a median notch; mesosternum with furcasternal protuberances contiguous only on basal corner; and nymphs with two subapical tubercles on mandibular tusks. Tortopsis is newly described for T. bruchianus (Navás), T. limoncocha sp. nov., T. obscuripennis (Domínguez), T. parishi (Banks), T. primus (McDunnough), T. puella (Pictet), T. sarae (Domínguez), T. spatula sp. nov., and T. unguiculatus (Ulmer). Tortopsis is characterized by: R sector of female fore wing without additional veins between R 2 and IR; female parastyli receptors C or V-shaped, with sockets opening towards median line; male gonopore associated with a claw-like structure; penes separated from the base; parastyli more than 5 times length of pedestals; parastyli curved in lateral view; nymphs with a single subapical tubercle on mandibular tusks. The study of available type material permitted inclusion of comparative diagnoses, with figures and redescriptions as needed. The male imago of the type species of Tortopus (T. igaranus Needham & Murphy) is described for the first time, as are the female adults of Tortopus bellus Lugo-Ortiz & McCafferty and T. harrisi Traver. Three new Neotropical species based on male and female adults are described: Tortopus arenales and Tortopsis limoncocha from Ecuador, and Tortopsis spatula from Colombia. Keys to separate the adults and nymphs of the genera of Polymitarcyidae, and for male and female adults of all the species of Tortopus and Tortopsis are presented, as well as line drawings, pictures and SEM photographs of important structures.Fil: Molineri, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentin

Description of Loricyphes froehlichi, a new genus and species of Leptohyphidae (Ephemeroptera) from São Paulo, Brazil

Loricyphes froehlichi gen. et sp. nov. is described and illustrated from nymphs, subimago and eggs. Diagnostic characters include, in the nymph: head, thorax and abdomen with very large and pointed tubercles; maxillary palp absent; femora very long and slender, ratio length/maximum width=5; forefemur without transverse row of setae at dorsum and with few chalazae; tarsal claws with 12–17 marginal denticles, submarginal denticles absent; abdominal segments II–VII very wide and laterally expanded forming a shallow cavity for the dorsal-positioned gills; and in the egg: conic in shape, with one pole truncated and the other acute, polar capsule apparently absent, chorionic plates longitudinally arranged between longitudinal elevated ridges, adhesive filaments absent. The new genus is superficially similar to Coryphorus (Coryphoridae) but presents synapomorphies of Leptohyphidae, and it is probably related to Tricorythodes based on gill morphology.Fil: Molineri, Carlos. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Mariano, Rodolfo. Universidade Estadual de Santa Cruz; Brasi

Contribución a la taxonomía de dos larvas de Leptohyphidae (Insecta: Ephemeroptera)

The morphology of the larvae of two species, Tricorythodes barbus and Tricorythopsis rondoniensis is revised. New geographical records from Brazil are provided for these species, as well as diagnosis, illustrations and discussions about useful characters to distinguish them from their closest relatives.La morfología larval de dos especies, Tricorythodes barbus y Tricorythopsis rondoniensis es revisada. Se proveen nuevos registros geográficos para ambas especies en Brasil, así como diagnosis, ilustraciones y discusión sobre los caracteres útiles para distinguirlas de otras especies cercanas.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. Fundacion Friedrich Ebert.; ArgentinaFil: P. Malzacher. 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; Argentin

Descripción del estado adulto de Cercobrachys peruanicus (Ephemeroptera: Caenidae)

Adults of both sexes of Cercobrachys peruanicus Soldán are described for the first time and the genus and species are reported from Bolivia. Diagnoses, illustrations, and environmental data are provided. Adults of C. peruanicus can be distinguished from the other species of the genus by the following combination of characters: many (8–16) cross veins in the fore wings, penes lobes completely fused, with posterior margin straight, and styliger plate with a broad median emargination posteriorly.Cercobrachys peruanicus Soldán are described for the first time and the genus and species are reported from Bolivia. Diagnoses, illustrations, and environmental data are provided. Adults of C. peruanicus can be distinguished from the other species of the genus by the following combination of characters: many (8–16) cross veins in the fore wings, penes lobes completely fused, with posterior margin straight, and styliger plate with a broad median emargination posteriorly.C. peruanicus can be distinguished from the other species of the genus by the following combination of characters: many (8–16) cross veins in the fore wings, penes lobes completely fused, with posterior margin straight, and styliger plate with a broad median emargination posteriorly.can be distinguished from the other species of the genus by the following combination of characters: many (8–16) cross veins in the fore wings, penes lobes completely fused, with posterior margin straight, and styliger plate with a broad median emargination posteriorly.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; ArgentinaFil: Goitia, Edgar. Universidad Mayor de San Simón; Bolivi

Growth rates of mayflies (Ephemeroptera) reared in the field differed under contrasting temperatures

Aquatic insect growth is tightly linked to environmental temperature. Growth rate tends to increase with rising temperatures. Growth rate integrates different factors related to population fitness, being partly responsible for species distribution. We aim to estimate daily growth rates from mayfly nymphs reared under different thermal regimes in the field, during five different periods from 2016 to 2018. Twelve species of mayflies were reared in mesocosms in six streams (from three altitudinal levels with a mean elevation 725, 1069, and 1509 m.a.s.l.). Additionally, we transplanted nymphs between lowest and highest pairs of streams, thus rearing them under a different thermal regime. Temperature and other ambient variables were recorded at regular intervals. Daily growth rate (dgr) of most species resulted lower in the higher pair of streams (colder sites) than in the medium and lower streams (warmer sites). Transplant experiment also clearly showed this tendency: (1) nymphs transplanted to colder thermal regimes grew slower than those reared under their natural (warmer) regime and (2) nymphs transplanted to hotter thermal regimes grew faster than those reared under their original (colder) regime. Nymphs of three species (Americabaetis alphus, Leptohyphes eximius, and Cloeodes penai) did not show differences in growth among treatments. Our findings relating sensitiveness of Ephemeroptera nymphs to small temperature changes suggest that the distribution of some species will modify by increases in temperature derived from climatic change.Fil: Hankel, Guillermo 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; ArgentinaFil: 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; Argentin

The larva of Neoneura confundens Wasscher and van’t Bosch, 2013 (Odonata, coenagrionidae) and key to the larvae of genus

The beautifully colored damselflies included in Neoneura Selys are divided in 28 species known from North, Central and South America. Larval stage is little known, only seven species were described at this stage. We describe and illustrate the final instar larva of Neoneura confundens for the first time. Adults associated to this larva correspond to the blue form of the species and are also discussed and illustrated. The larva of N. confundens is similar to other Neoneura larvae, showing 1 premental seta and a well-marked nodus in caudal lamellae, but it can be differentiated by having fringed posterior margin in all tibiae and in middle and hind tarsi, among other characters. A key to known larvae of Neoneura and new records extending the species range in the southern cone are provided.Fil: Rodríguez, José Sebastián. 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; ArgentinaFil: 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; Argentin

A new family, Coryphoridae (Ephemeroptera: Ephemerelloidea), and description of the winged and egg stages of Coryphorus

A new family Coryphoridae is proposed in the superfamily Ephemerelloidea for the monotypic genus Coryphorus. Characters that distinguish Coryphoridae from all other Ephemerelloidea are discussed. The male imago, male subimago, female imago, and egg of Coryphorus aquilus Peters are described for the first time.Se propone a Coryphoridae como una nueva familia de Ephemerelloidea para el genero monotipico Coryphorus. Se discuten los caracteres que distinguen a Coryphoridae del resto de los Ephemerelloidea. Se describen por primera vez el imago macho, subimago macho, imago hembra y huevo de Coryphorus aquilus Peters

The adults and nymphs of Asthenopus angelae new species (Ephemeroptera: Polymitarcyidae) from Argentina, Bolivia, Brazil and Colombia

Asthenopus angelae sp. nov. is described based on male and female imagos and associated nymphs from Argentina,Bolivia, Brazil and Colombia. The new species described is similar to A. curtus (Hagen). The nymphal and adult femalestages are indistinguishable from those of that species. The male adults can be separated from its congeners by thefollowing characters: penes tubular, with well developed median basal protrusion, curved ventro-medially, with apexacutely projected, furrow separating penial lobe from median basal protrusion reduced or absent; forceps relativelyslender; forelegs of male 0.6?0.7 × the length of the forewing; fore tarsal claws slightly widening distally; fore wings with5?11 marginal intercalary veins relatively short.Fil: De Souza, Marcia Regina. Universidade Federal do Rio de Janeiro; BrasilFil: Molineri, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentin

The presence of rainbow trout reduces drift of aquatic insects in Yungas streams (Tucumán, Argentina)

. La deriva o transporte de individuos aguas abajo es un fenómeno importante de ríos y arroyos, ya que la mayoría de los organismos acuáticos participan de ella en algún período de su ciclo de vida. Este trabajo describe el ensamble de deriva de macroinvertebrados de diez sitios en ocho ríos de montaña de Tucumán, y evalúa el efecto de la presencia de trucha arco iris (Oncorhynchus mykiss Walbaum), un pez exótico y depredador visual, sobre esta fracción de la comunidad. Se identificaron 31 familias de invertebrados acuáticos en la deriva, principalmente insectos inmaduros y en menor medida hidrácaros (Acari: Hydrachnidia), oligoquetos (Annelida: Oligochaeta) y nematodos (Nematoda). La riqueza y diversidad de los sitios fue similar en todos los ríos, excepto al comparar tramos con y sin truchas en un mismo arroyo. Las muestras provenientes de ríos sin trucha o con baja densidad de ellas no mostraron cambios significativos en densidad de deriva de macroinvertebrados. En cambio, en los ríos con altas densidades de trucha se observó una notoria disminución de algunos insectos (con individuos grandes): Baetidae (Ephemeroptera), Gripopterygidae (Plecoptera) y Leptoceridae (Trichoptera). Por el contrario, en estos ríos aumentó la densidad de pequeños Diptera, Hidracarina, Nematoda y Oligochaeta.The drift or transport of individuals downstream is an important phenomenonof rivers and streams, since most aquatic organisms participate in it at some period of theirlife cycle. This work describes the assemblage of macroinvertebrate drift from ten sites ineight mountain streams of Tucumán, and evaluates the effect of the presence of rainbow trout(Oncorhynchus mykiss Walbaum), an exotic fish and visual predator, on this fraction of thecommunity. Thirty-one (31) families of drifting aquatic invertebrates were identified, mainlyimmature insects and to a lesser extent water mites (Acari: Hydrachnidia), oligochaetes(Annelida: Oligochaeta) and nematodes (Nematoda). The richness and diversity of the siteswith trout did not differ from the others, except when comparing lower and upper reaches ofa same stream. Samples from rivers without trout or with low density of trout did not showsignificant changes in drift density of macroinvertebrates. In contrast, in rivers with high troutdensities, a notable decrease in insect taxa was observed (those with large sized individuals):Baetidae (Ephemeroptera), Gripopterygidae (Plecoptera) and Leptoceridae (Trichoptera). Onthe contrary, the density of small Diptera, water mites, oligochets and nematodes increasedin trout-streams.Fil: Serra Greppi, Iris Carla. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: 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; Argentin