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Sexual intercourse involving giant sperm in Cretaceous ostracode
R Matzke-Karasz1, R J Smith, R Symonova
1Department of Environmental and Geosciences, Palaeontology, and GeoBioCenter, Ludwig Maximilians University (LMU), 80333 Muenchen, Germany. r.matzke@lrz.uni-muenchen.de
Science (New York, N.Y.)
|June 23, 2009
Summary
Giant sperm reproduction, observed across diverse animals, has remained stable for over 100 million years in ostracodes. Fossil evidence reveals this reproductive strategy, despite its costs, is evolutionarily successful.
Area of Science:
- Evolutionary biology
- Paleontology
- Reproductive biology
Background:
- Giant sperm reproduction is observed in diverse animal groups.
- Previous studies in Drosophila explored selection pressures on giant sperm, but long-term stability remained unknown.
Purpose of the Study:
- To investigate the long-term evolutionary stability of giant sperm reproduction in ostracodes.
- To provide evidence for the persistence of this reproductive strategy over geological timescales.
Main Methods:
- Utilized sub-micrometer-resolution synchrotron quantitative phase tomography (holotomography).
- Analyzed exceptionally well-preserved 3D Cretaceous ostracode fossils from the Santana Formation in Brazil.
Main Results:
- Demonstrated that ostracode reproduction with giant sperm persisted for at least 100 million years.
- Identified remnants of male sperm pumps and giant female sperm receptacles in fossilized specimens.
Conclusions:
- Reproduction with giant sperm is an evolutionarily successful strategy, persisting for over 100 million years in ostracodes.
- The presence of specialized reproductive structures in fossils supports the long-term viability of this trait despite potential high costs.
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