Diel changes in embryonic maturation in two species of marine cladocerans in Guanabara Bay, Rio de Janeiro, Brazil

Two species of marine cladocerans, Penilia avirostris Dana, 1852 and Evadne tergestina Claus, 1877 were collected in thirteen samples at a fixed station in Guanabara Bay, Rio de Janeiro (30-meter depth) by means of vertical tows with a 200 µm mesh size net at different times from September 12th to 15th, 1995. The parthenogenetic females of Evadne tergestina bore mature embryos (with pigmented eye) only in the samples collected at night, whereas Penilia avirostris at any time of day. This phenomenon was interpreted based on the greater visibility of the Evadne tergestina brood: one of the benefits for embryo maturing during the darkness period would be a decrease of predation on gravid females

Record of Pleopis schmackeri (Poppe) (Branchiopoda, Onychopoda) in the Guanabara Bay, Rio de Janeiro, Brazil

A first recordof Pleopis schmackeri (Poppe,1889) (Branchiopoda, Onychopoda) in the Guanabara Bay, Rio de Janeiro, Brazilis described.This marine cladoceran species occurred in zooplanktonic samples obtained on June 26, 2000, with densities ? 4.0 ind.m-3. Its presence may berelated with inflow of coastal waters to the bay