Meanwhile, among the invertebrates:

A fossil found in Herefordshire, England, may be the oldest record of an animal that is unarguably male. Scientists report today in the journal Science that the tiny crustacean, only two-tenths of an inch long, had an unmistakable penis.

In the paper published in today's issue, the scientists name the creature Colymbosathon ecplecticos, which they say means swimmer with a large penis.

—— James Gorman, “Fossil Find Hailed as Earliest Recorded Male”, New York Times, 4 December 2003