By Rebecca Morelle – BBC News science reporter
A shrimp-like creature may have to forfeit its claim to be the longest abstainer from sex in the animal world.
The discovery of three living male specimens casts doubt on the idea that the Darwinulidae family has been female and asexual for 200 million years.
Darwinulids produce eggs which do not need to be fertilised by sperm.
But a team of scientists, writing in a Royal Society journal, cannot say yet whether the newly found males actually perform a sexual function.
If they do not, if researchers can show the males are just some evolutionary hangover that is really no longer needed for reproduction – then the creatures will retain their famed celibacy status.