Identification Accuracy of Bosminidae in Minnesota Lakes
Bosminidae are a species of freshwater zooplankton and serve a crucial role in the ecosystem (1). Bosmina longirostris is a species native to Minnesota and is characterized by the presence of a mucro and a small, oval lateral headpore, whereas, Eubosmina coregoni is not native to Minnesota, does not have a mucro and has a a large, circular, and thickened lateral headpore located far away from anterior margin (2). The Minnesota DNR uses the presence of a mucro to identify these species, however this has also been found to be unreliable in other geographical contexts compared to the more reliable method of identification using pores. Monthly zooplankton samples were taken from May to September, 2025 in Sturgeon, Green, and Pelican lakes (Minnesota, USA). 20 E. coregoni and 20 B. longirostris individuals from each sample were wet mounted and examined under a compound microscope. We recorded the presence or absence of a mucro, the longest diameter of the headpore, and the distance of the headpore from the anterior and ventral margins. We found the presence or absence of a mucro is a reliable way to identify Bosminidae species in Minnesota lakes. We did find one individual we believe to be a hybrid because it had both pores. Our results show the Minnesota DNR is accurately identifying Bosminidae species, however more research should be done to look at possible hybrids.