One‐Sided Ejaculation of Echidna Sperm Bundles

S. D. Johnston, B. Smith, M. Pyne, D. Stenzel and W. V. Holt
The American Naturalist
Vol. 170, No. 6 (December 2007), pp. E162-E164
DOI: 10.1086/522847
Stable URL:
Page Count: 3
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One‐Sided Ejaculation of Echidna Sperm Bundles
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Abstract: We report for the first time an unusual ejaculatory mechanism in the short‐beaked echidna in which each side of the bilaterally symmetrical, rosettelike glans penis is used alternately, with the other being shut down. This is unparalleled in mammals but is reminiscent of the use of hemipenes in squamate reptiles, providing further reproductive evidence of a sauropsidian lineage in the Monotremata. Further, we describe the occurrence of motile sperm bundles in ejaculated echidna semen and provide scanning electron micrographs of their morphology. Sperm bundling appears to confer increased sperm motility, which may provide the potential for sperm competition between males.

Notes and References

This item contains 9 references.

Literature Cited
  • ['Augee, M., B. Gooden, and A. Musser. 2006. Echidna: extraordinary egg‐laying mammal. CSIRO, Collingwood.']
  • ['Djakiew, D., and R. C. Jones. 1983. Sperm maturation, fluid transport, and secretion and absorption of protein in the epididymis of the echidna, Tachyglossus aculeatus. Journal of Reproduction and Fertility 68:445–456.']
  • ['Gist, D. H. 1999. Male reproductive system: reptiles. Pages 60–70 in E. Knobil and J. D. Neill, eds. Encyclopedia of reproduction. Vol. 3. Academic Press, Sydney.']
  • ['Griffiths, M. 1989. Tachyglossidae. Pages 407–435 in D. W. Walton and B. J. Richardson, eds. Fauna of Australia. Vol. 1B. Mammalia. Australian Government Publishing Service, Canberra.']
  • ['———. 1999. Monotremes. Pages 295–302 in E. Knobil and J. D. Neill, eds. Encyclopedia of reproduction. Vol. 3. Academic Press, Sydney.']
  • ['Jones, R. C., D. Djakiew, and J. L. Dacheux. 2004. Adaptations of the short‐beaked echidna Tachyglossus aculateus for sperm production, particularly in an arid environment. Australian Mammalogy 26:199–204.']
  • ['Rismiller, P. D., and R. S. Seymour. 1991. The echidna. Scientific American 264:96–103.']
  • ['Temple‐Smith, P., and T. Grant. 2001. Uncertain breeding: a short history of reproduction in monotremes. Reproduction Fertility and Development 13:487–497.']
  • ['Williams, T. D. 1999. Avian reproduction: overview. Pages 325–336 in E. Knobil and J. D. Neill, eds. Encyclopedia of reproduction. Vol. 1. Academic Press, Sydney.']