Tardigrades from Larus dominicanus Lichtenstein, 1823 nests on the Argentine Islands (maritime Antarctic)

Abstract

Tardigrada in Antarctic regions are poorly known. The aim of this study was to examine for tardigrades the nests material of the kelp gull (Larus dominicanus Lichtenstein, 1823) in maritime Antarctic and discuss the possible ways of migration and dispersion of tardigrades by birds. We also discuss the influence of bird’s guano on the communities of microscopic invertebrates (mainly tardigrades). In the positive samples (mainly bryophytes and lichens) of seven Larus dominicanus nests, collected on Ardley Island (near Fildes Peninsula) and Argentine Islands, ca. 850 tardigrades and their eggs were found. In total, 13 taxa (including Ramajendas sp.) were identified, and four are new to science: Bryodelphax olszanowskii sp. nov., Diphascon puchalskii sp. nov., D. rudnickii sp. nov. and Hypsibius conwentzii sp. nov.. Bryodelphax olszanowskii sp. nov. differs from known Bryodelphax species in the weglarskae group mainly by having a different ventral plate configuration. Belonging to the pingue group, D. puchalskii sp. nov. differs from other species by some quantitative characters and D. rudnickii sp. nov. by having the first and second macroplacoids situated very close to each other. Hypsibius conwentzii sp. nov. differs from other species of the genus Hypsibius, with two macroplacoids and septulum, by some morphological and morphometric characters. Summarizing, Antarctic tardigrades are a very diverse group, and birds can be responsible for translocation of small invertebrates (including tardigrades) inside of various parts of plants and lichens. They also deposit large amounts of guano, which provides a lot of nutrients for poor tundra ecosystems and support small invertebrate communities.