Renate Matzke-Karasz and co-authors publish on giant sperm in Cretaceous Ostracodes in Science

Renate Matzke-Karasz and co-authors provide evidence that sexual intercourse involving giant sperm - at least in Cretaceous ostracodes - can be an evolutionary successful strategy despite its high cost.
Science 19 June 2009: Vol. 324. no. 5934, p. 1535; DOI: 10.1126/science.1173898

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Sexual Intercourse Involving Giant Sperm in Cretaceous Ostracode

R. Matzke-Karasz,1,* R. J. Smith,2 R. Symonova,3 C. G. Miller,4 P. Tafforeau5

Reproduction with giant sperm occurs in distinct groups scattered over the animal kingdom. Although experiments in Drosophila assessed the influence of different selection pressures on this character, no information was available on its long-term stability. Sub-micrometer-resolution synchrotron quantitative phase tomography (holotomography) of exceptionally well-preserved three-dimensional Cretaceous ostracode fossils from the Brazilian Santana Formation indicates that ostracode reproduction with giant sperm persisted for at least over the past 100 million years. Remnants of the male sperm pumps as well as giant, inflated female sperm receptacles evidence that, despite high costs, reproduction with giant sperm can be an evolutionary successful strategy.

1 Department of Environmental and Geosciences, Palaeontology, and GeoBioCenter, Ludwig Maximilians University (LMU), 80333 Muenchen, Germany.
2 Lake Biwa Museum, Kusatsu, Shiga 525-0001, Japan.
3 Department of Zoology, Charles University, 12844 Prague, Czech Republic.
4 Department of Palaeontology, Natural History Museum, London SW7 5BD, UK.
5 European Synchrotron Radiation Facility (ESRF), 38043 Grenoble, France.