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Journal Article

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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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
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