Diversity of freshwater hydrozoans from Neotropical region: an annotated inventory of species

Introduction: Worldwide, six genera of the class Hydrozoa are recognized in continental waters: cosmopolitan Hydra, colonial Cordylophora and Pachycordyle, medusae Craspedacusta Limnocnida little polyp Calpasoma. Even though interest cnidarians has grown recent years, those restricted to freshwater continue be relegated there is even published information on ubiquity certain species. In Neotropical region, knowledge about its distribution still very scarce.
 Methods: We reviewed global literature subject different online database platforms, presenting this work a nomenclator, including discussions status some species provide most identification key. 
 Results: This analysis reveals that 15 countries corresponding finding hydrozoans been reported. Panama, Brazil Argentina with highest number reports.
 Conclusions: The heterogenity environments where these have found (from Strait Magellan Mexico) offers clear vision their wide great adaptability environments. study evidence gap exists hidrozoans importance systematizing current distribution, biology ecology, especially for considered invasive.