Two new species of Simocephalus and Chydorus (BRANCHIOPODA: Cladocera) from Lake Usorisanko (Lake Osorezanko)

Abstract

A detailed examination of Simocephalus vetulus and Chydorus sphaericus, which are considered representative zooplankton of Lake Usoriyama, located almost in the center of the Shimokita Peninsula in the northernmost part of Honshu, revealed that they were misidentified. In this paper, we have given new names to Simocephalus vetulus and Chydorus sphaericus as Simocephalus usorikoensis Tanaka & Ogawa n. sp and Chydorus osorezanensis Ogawa & Tanaka n. sp, respectively.