Tardigrade fauna from two biogeographic regions of Patagonia (Río Negro province, Argentina)

CLAPS, M. C.; ROSSI, G. C.; ROCHA, A. M.

Tübingen, Alemania

Simposio; 11th International Tardigrade-Symposium; 2009

Samples of lichens and mosses were obtained in two protected areas of Río Negro Province located at different biogeographic regions of Argentina: subantartic forests and Patagonian steppe. Fourteen samples were collected in locations of the Nahuel Huapi National Park and nine in the Reserve Natural of Somuncurá Plateau. The subantartic region is characterized by the presence of Nothofagus forests. The annual mean precipitation is approximately 800 mm and the mean temperature 8.3 ºC (mean warm temperature: 12.9 and mean cold temperature: 1.3). The Somuncurá plateau is a massive 25,000 km2 volcanic plain conformed by superimposed layers of basalt flows and elevated between 600 – 1,600 m above the sea level. Annual mean temperature is around 10 °C and precipitation around 200 mm. At highest elevations, winter temperature is -25 °C and summer temperature is above 35 °C. A total of twenty eight species belonging to ten genera were found. Eighteen species were collected in the samples of Nothofagus forests meanwhile in those obtained in the plateau thirteen species were identified. The assemblages recorded in the mentioned regions were clearly different. A cluster analysis (UPGMA technique) perfumed with Baroni Urbani-Buser coefficient revealed similarities between some locations. Ramazzottius baumanni and Milnesium tardigradum are present in some samples of both sectors. Milnesioides exsertum is recorded for the first time after its discovery in Nothofagus forests of Australia and New Zealand in three samples of Nahuel Huapi. Four new species obtained in samples of Somuncurá plateau are described for science (three species of Macrobiotus and one of genus Echiniscus).