Relocation of Chydorus barroisi and related species (Cladocera, Chydoridae) to a new genus and description of two new species

Abstract

Five taxa already in the literature are here removed from Chydorus to their own genus Ephemeroporus, and two new species — E. acanthodes and E. archboldi — are described, with E. acanthodes being designated the type species of the genus. These taxa, plus at least nine undescribed species and others undoubtedly waiting to be sorted out, constitute a tightly circumscribed group of species morphologically. The first two species described — E. barroisi and E. poppei — are nomina dubia for the present, as no specimens exist from the original collections, nor are any available from the type localities or reasonably close thereto. E. hybridus from Brazil has been characterized in greater detail through the availability of specimens from the type series, which has enabled one of the species in the E. hybridus group from North America to be judged conspecific with reasonable certainty. E. tridentatus, from Brazil, has been restored as a valid species, and the highly distinctive E. phintonicus from Sardinia and Algeria constitutes the seventh species in the genus. Chydorus nitidulus and Chydorus tilhoi, which have been suggested to be members of the barroisi complex, are not. What are presently called E. barroisi and E. hybridus, except for E. hybridus, sens. str., each consists of a cluster of species sharing the same number of teeth on the labrum and shell. Because of their wide, distribution, abundance, and frequency of occurrence, especially in South Asia, the species in the E. barroisi group will be especially meaningful to sort out.