One‐Sided Ejaculation of Echidna Sperm Bundles

@article{Johnston2007OneSidedEO,
  title={One‐Sided Ejaculation of Echidna Sperm Bundles},
  author={Stephen D Johnston and B Smith and Michael Pyne and Deborah J. Stenzel and William V. Holt},
  journal={The American Naturalist},
  year={2007},
  volume={170},
  pages={E162 - E164}
}
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… Expand
Formation and Dissociation of Sperm Bundles in Monotremes1
TLDR
It is concluded that the development of sperm bundles in the monotreme epididymis mandates that they require a time-dependent process to be capable of fertilizing an ovum. Expand
Post‐ejaculatory modifications to sperm (PEMS)
TLDR
It is predicted that PEMS will exhibit widespread phenotypic plasticity mediated by sperm–female interactions, and the successful execution of PEMS thus has important implications for variation in fitness and the operation of post‐copulatory sexual selection. Expand
The Unique Penile Morphology of the Short-Beaked Echidna, Tachyglossus aculeatus
TLDR
It is confirmed that the echidna penis contains many of the same overall structures and morphology as other mammalian penises and a number of features homologous with reptiles. Expand
Reproductive Biology in Egg-Laying Mammals
TLDR
This review focuses on the reproductive biology of monotremes and discusses works that unravel genes involved in lactation, testicular descent, gamete biology and fertilization, and early development and the evolution of the complex sex chromosome system in platypus and echidna. Expand
Developmental and Evolutionary Origins of the Amniote Phallus.
TLDR
Conservation of the embryonic origins, morphogenetic processes, and molecular genetic mechanisms involved in external genital development across Amniota supports derivation from the common ancestor of amniotes, and suggests that lineage-specific divergence of later patterning events underlies the variation observed in extant adult amniote phallus morphology. Expand
Monotremes provide a key to understanding the evolutionary significance of epididymal sperm maturation.
TLDR
It is suggested that this intriguing cooperative strategy used by monotreme sperm represents an early form of epididymal maturation that appears to have been elaborated upon during the evolution of higher mammals, possibly as an adaptation for sperm competition. Expand
Evolution of intra‐ejaculate sperm interactions: do sperm cooperate?
TLDR
Current evidence insufficient to support the concept of sperm control over their form or function is found, and sperm heteromorphism and conjugation should be interpreted not as cooperation but rather as traits selected at the level of the male, much like other ejaculatory traits such as accessory gland proteins and ejaculate size. Expand
Molecular insights into the divergence and diversity of post-testicular maturation strategies
TLDR
Here, literature pertaining to the nature and the physiological role of epididymal maturation and subsequent capacitation in comparative vertebrate taxa including representative species from the avian, reptilian, and mammalian lineages are reviewed. Expand
Cool Sex? Hibernation and Reproduction Overlap in the Echidna
TLDR
The mating of males with torpid females is the result of extreme competition between promiscuous males, while re-entry into hibernation by pregnant females could improve the possibility of mating with a better quality male. Expand
Sperm conjugation in mammal reproductive function: Different names for the same phenomenon?
TLDR
A new classification system is proposed for this phenomenon that might clearly unify the criteria used to describe this behavior, and findings regarding the components that enable sperm to adhere; sperm behavior when deposited in the female reproductive tract are summarized. Expand
...
1
2
3
...

References

SHOWING 1-10 OF 10 REFERENCES
Adaptations of the short-beaked echidna Tachyglossus aculateus for sperm production, particularly in an arid environment.
TLDR
It is suggested that T. aculateus is also specialised for sperm competition, and the size of their testes and number of extragonadal sperm compared with other mammals are indicative that they are involved in sperm competition. Expand
Echidna: Extraordinary Egg-Laying Mammal
TLDR
The authors reveal some fascinating new findings, showing how echidnas are masters of their environment, and not simply some sort of mammal ‘test model’ that went wrong. Expand
Sperm maturation, fluid transport, and secretion and absorption of protein in the epididymis of the echidna, Tachyglossus aculeatus.
TLDR
Denatured, linear-gradient polyacrylamide gel electrophoresis of micropuncture samples showed that 1 protein which is not present in blood plasma is present in rete testis fluid, and a glycoproteins is absorbed by the ductuli efferentes. Expand
Uncertain breeding: a short history of reproduction in monotremes.
TLDR
The evidence suggests that although annual breeding seasons are regionally predictable, individual adult females breed unpredictably, with some showing breeding intervals of many years, and better knowledge of factors that influence breeding intervals may improve the success of monotreme captive breeding programmes. Expand
Avian reproduction : overview
  • 1999
Avian reproduction: overview. Pages 325-336 in E. Knobil and
  • Encyclopedia of reproduction
  • 1999
Male reproductive system : reptiles
  • Encyclopedia of reproduction
  • 1999
Male reproductive system : reptiles
  • Pages Encyclopedia of reproduction
  • 1999
Male reproductive system: reptiles. Pages 60-70 in E. Knobil and
  • Encyclopedia of reproduction
  • 1999
The echidna
  • Scientific American
  • 1991