5,000 year-old spermatozoa in quaternary Ostracoda (Crustacea).

Fossil spermatozoa are recorded for the first time in freshwater ostracods (small bivalved crustaceans) from Holocene sediments at sites in the United Kingdom and Germany. Exceptional conditions at these sites have resulted in the preservation of chitinous "soft parts", including limbs, the remains of Zenker's Organs (sperm pumps that are part of the male reproductive apparatus in cypridoidean ostracods) and spermatozoa from eight different species. Comparisons are made with spermatozoa from living ostracods and the implications of these discoveries for evolutionary studies of reproductive modes are discussed.