Distribution of Stygarctus bradypus Schulz, 1951 (Tardigrada, Heterotardigrada) at the southern edge of Itamaracá Island (PE, Brazil).

Abstract

This work aimed to investigate the spatial and temporal distribution of Stygarctus bradypus Schulz, 1951 (Tardigrada, Heterotardigrada) in a sandy beach in the southern edge of Itamaracá Island, 40 km north far from Recife (PE, Brazil). Samples were taken in two different periods of the year characterized by dryness and rain, along two coastal transects through the intertidal zone, during low tides. One identified 337 specimens of Stygarctus bradypus. There was a significant difference between the populations of S. bradypus from the two transects and between the steps of the beach, but not between the sedimentary layers and between the two periods of the year. It was concluded that this species does not have its distribution influenced by the sediments granulometry nor for the presence of interstitial water, preferentially colonizing the upper mid-littoral of the studied beach, concentrating its population between 10 cm and 20 cm depth in the sediments throughout the whole year.