An illustrated guide to the identification of cladoceran subfossils from lake sediments in northeastern North America: part 2-the Chydoridae.

The diverse members of the cladoceran family Chydoridae are typically well preserved in lake sediments, although identifications of chydorids using subfossil remains still differ from identifications using whole animals. To address this issue, we analyzed and photographed chydorid subfossil remains from lakes in eastern Canada and northeastern USA and compiled this information into an illustrated identification guide for this region, which is characterized by high chydorid species richness. We provide detailed descriptions of commonly recovered body parts for each species, including headshields, carapaces, postabdomens, and postabdominal claws. We describe 29 chydorid taxa, discuss the distribution of these taxa within North America, and compare morphology with related species described from Alaska or northern Europe, the only other regions for which subfossil chydorid identification guides are available. [ABSTRACT FROM AUTHOR]