Guillermo Debandi

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.

Prioridades de conservación aplicando información filogenética y endemicidad: un ejemplo basado en Carabidae (Coleoptera) de América del Sur austral

Sobre la base de la informacion distribucional de las especies de Carabidae (Coleoptera) de America del Sur austral, se reconocieron 17 areas de endemismo. Para cada una de ellas se estimo la diversidad gamma, el porcentaje de endemismo, el valor filogenetico y la complementariedad, exceptuando Juan Fernandez del cual no se pudo obtener ningun valor filogenetico. El calculo del valor filogenetico se realizo a traves del uso de cuatro indices, el valor filogenetico sin ninguna modificacion (W), considerando la endemicidad (We), y sus respectivas estandarizaciones (Ws y Wes). Los resultados muestran que la estandarizacion del valor filogenetico (Ws) produce un sesgo cuando los cladogramas difieren en tamano y que el complemento entre areas es una herramienta secundaria de gran utilidad. Sin embargo, los resultados muestran que para determinar la importancia de las areas, el complemento debe ser usado en conjunto con la diversidad especifica y la endemicidad. Las comparaciones de los resultados obtenidos usando W, We y analisis de complementariedad estrictos y modificados muestran que el valor filogenetico que admite endemicidad (We) puede ser aplicado como unico valor para determinar la importancia de cada area. Aplicando We, las seis primeras areas seleccionadas acumulan el 72 % del valor filogenetico y el 74 % de la diversidad gamma de los carabidos de America del Sur austral, mientras que ninguno de los otros parametros usados acumula el 70 % de las especies antes de sumar la septima area. Las seis areas seleccionadas son la Selva valdiviana, las Sierras pampeanas, Coquimbo, Patagonia occidental, Chile central y La Araucania. Es de hacer notar que las Sierras pampeanas y la Patagonia occidental son ambientes de pastizales, Coquimbo y Chile central son ambientes aridos y semiaridos, y solo la Selva valdiviana y Araucania son tipicos bosques australes

Basking behaviour in two sympatric herbivorous lizards (Liolaemidae: Phymaturus) from the Payunia volcanic region of Argentina

We studied several aspects of the thermal biology of two coexisting saxicolous species of the genus Phymaturus (Liolaemidae) at the Payunia, a volcanic region in Argentina where harsh conditions prevail. We marked individuals in grids and assessed the environmental conditions when the individuals showed their maximum activity (i.e. when more than 50% of marked individuals were active), the time spent basking, and the postural behaviour in relation to different cloudiness conditions. We found that temperatures recorded when the species exhibit their peaks of activity were higher for Phymaturus payuniae, the smaller species, during the summer at one of the three studied sites. Phymaturus roigorum exhibited the longest basking periods, but during these longer periods cloudy conditions prevailed. Both species adopted a head-up posture when conditions were sunny and a head-down posture when under cloudy conditions. This is the first contribution where thermal aspects of two sympatric species of Phymaturus are evaluated.

Prolonged larval development in the Critically Endangered Pehuenche’s frog Alsodes pehuenche: implications for conservation

Overwintering is an anuran strategy to survive in cold-temperate climates. Those aquatic species that withstand harsh conditions and short growing seasons are candidates for having long larval periods. Prolonged larval development, which includes overwintering for more than two years, has been reported for North-American and Euro-Asiatic species, but this strategy has been poorly studied in the Southern Hemisphere. Alsodes pehuenche is an endemic frog from the high Andes mountains of Argentina and Chile, recently categorized as Endangered by the Asociacion Herpetologica Argentina (AHA) and as Critically Endangered by the International Union for Conservation of Nature (IUCN). We studied egg laying in this species and its larval development by marking tadpoles with elastomers. We found that eggs are laid in clumps at the beginning of summer. The larval cycle includes four winters, although a fifth winter should not be ruled out. This is the first study that demonstrates a long larval development (four winters) in South-American species and has important implications for conservation biology.

DNA Barcoding of Phymaturus Lizards Reveals Conflicts in Species Delimitation within the patagonicus Clade

Abstract Under the DNA Barcode initiative, we used the mitochondrial locus cytochrome c oxidase I to test if this molecular marker would reliably distinguish among lizard species of the patagonicus clade of Phymaturus. Using 18 described species and two populations of unidentified species, we calculated intra- and interpopulation genetic distances for all operational taxonomic units and performed phylogenetic reconstructions using maximum parsimony and maximum likelihood. We identified different species that share the same barcode index number (BIN). We recorded only 12 of the 18 previously described species and one candidate species from the new population. By comparing our results with published morphological and molecular phylogenies, as well as with previous debates, we propose possible explanations for this. In some cases (such as the group with the same BIN formed by Phymaturus spurcus, Phymaturus spectabilis, Phymaturus excelsus, and Phymaturus agilis), where other authors debated the identity of the species, we suggest that the low genetic distances could be attributable to the presence of one species with high polymorphism. On the other hand, in geographically isolated species such as the group formed by Phymaturus payuniae and Phymaturus nevadoi, the group formed by Phymaturus somuncurensis and Phymaturus ceii, and the group formed by Phymaturus indistinctus and Phymaturus videlai, the topology of the phylogenetic trees indicates that the low genetic distances (also found by other authors analyzing cytochrome b) could be attributable to shared ancestral polymorphism resulting from incomplete lineage sorting.

First record of the American bullfrog Lithobates catesbeianus (Shaw, 1802) in Mendoza province, Argentina

We discovered a well established populationof L. catesbeianus in Mendoza province, San Carlosdepartment, Capiz locality (33° 41’ 11’’S, 68° 59’09’’ W; elevation: 920 m) and other nearby localitiesat Tunuyan department. Thisrecord extends the distribution range of this species270 km S-SE from Calingasta, San Juan, and 400km W-SW from Villa Dolores, Cordoba. The regionis part of the Monte phytogeographic province,which is characterized by an arid climate with meanannual temperature of 17.7oC (mean annualminimum and maximum: -1.4 and 38.0oC,respectively) and mean annual rainfall of 331.2 mm,which occurs mainly in summer.