A survey of freshwater Tardigrada of the Mississippi River and U.S. driftless area

The Mississippi River is the largest river in the United States of America (U.S.). While the Mississippi River provides a habitat for many animal species, much of the river has not been explored for microscopic organisms, like zooplankton, microfauna, and tardigrades. In the current study, we collected sixty freshwater samples from the Mississippi River and other freshwater systems in the U.S. Driftless Area. A total of eighty-five tardigrades were collected and four different species of tardigrades were identified using morphological analyses. The results presented here are the first peer-reviewed records of tardigrade species documented from the Mississippi River and other freshwater systems in the U.S. Driftless Area. The tardigrade species Grevenius granulifer, Pseudobiotus kathmanae, and Thulinius augusti were collected from the Mississippi River. The tardigrade species Dactylobiotus cf. dispar and Thulinius augusti present new biogeography records for the state of Iowa. These records update our knowledge of tardigrade biogeography and ecology in North America.