DAPHNIA-OBTUSA KURZ, 1874 EMEND SCOURFIELD, 1942 FROM AUSTRALIA

Specimens of Daphnia found in Lake Burley Griffin in December 1994 (au stral summer), were taken into laboratory culture where males and ephi ppial females were generated. All the key morphological features of th e females, males and ephippia (resting eggs) fitted those described fo r Daphnia obtusa Kurz, 1874 emend Scourfield, 1942 not yet recorded fr om Australia. There were major differences between the specimens from Lake Burley Griffin and descriptions of D, jollyi, the only other spec ies from the subgenus Daphnia in Australia which has a fringe of long setae in the mid-region of the ventral margin of the carapace. In addi tion, D. jollyi is endemic to the south-west of Western Australia. The discovery of D. obtusa does not provide evidence for the existence of this taxon in Australia since the breakup of Gondwana in the Cretaceo us. Its discovery in an artificial lake opened in 1964, and which has been extensively sampled without detection of this species over the la st 10-20 years, suggests a recent introduction from overseas.