This is the first attempt to compile a comprehensive and updated species list for Hydrozoa in the Arctic. encompassing both hydroid and medusa stages and including Siphonophorae. We address the hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic by Hydrozoa after the Last Glacial Maximum. Presence-absence da... https://www.bempresas.com/