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Oviparous X viviparous hybrid
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by viandy on October 4, 2008
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The instance of these hybrids was mentioned and discounted in the copperhead / blacksnake thread below. I was reminded of Ludwid Trutnau discussion of Cerastes sp in Venomous Snakes, p141;
An especially rare event occurred when M.Lehmann had a cross-breeding of his Cerastes cerastes male with his extremely large C.vipera female, particularly since the first mentioned species is oviparous and the second viviparous. On May 23, 1994, the female C.vipera copulated with a male C.cerastes. On August 2, 1994, this female gave birth to 11 healthy young and at the same time passed 3 infertile eggs.
It goes on to say that the young had intermediate characteristics of both species. This always seemed suspect to me, sounding more like a prank or disinformation than an actual occurrence. But, if I had to pick who to believe, Trutnau or myself, I would probably choose Trutnau, he knows alot more about this than I do.
A big difference between this observation and the one below is that these two snakes are in the same genus. That's always seemed very strange to me also. Does anyone know of this reoccurring or have any other comments?
Andy
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RE: Oviparous X viviparous hybrid
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by tj on October 4, 2008
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Interesting. Anything I've ever read says that all cerastes are egg layers. But, vipera seem to hatch almost immediately after eggs are layed.
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RE: Oviparous X viviparous hybrid
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by Cro on October 4, 2008
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This does not involve hybrids, but I seem to remember that there is one of the Old World Vipers that in parts of it's range is Oviparous, and in other parts of it's range is Viviparous. I just can not remember which one it is though.
Best Regards John Z
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RE: Oviparous X viviparous hybrid
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by LarryDFishel on October 4, 2008
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That would be Echis. Very closely related to Cerastes. I suspect they are both in sort of a transitional area between oviparous and ovoviviparous.
Not really the same league as a fully oviparous species from one genus mating with a viviparous species from another genus...
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RE: Oviparous X viviparous hybrid
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by Cro on October 4, 2008
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Ok, here is a wierd referenc to what snakes have supposedly been hybridized.
http://74.125.45.104/search?q=cache:yuPwJ4F5hRwJ:www.creationresearch.org/crsq/articles/42/42_3/CRSQ%252012-05%2520Snakes%2520article.pdf+crotalus+x+sistrurus&hl=en&ct=clnk&cd=18&gl=us
Best Regards John Z
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RE: Oviparous X viviparous hybrid
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by kacz on October 4, 2008
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This is the way I learned it 40+ years ago. It may be true, or not. While many snakes are egg-laying (oviparous) none are truly viviparous. This would require the placental attachment to the mother, found in most mammals. Instead, live-bearing snakes are ovaviviparous. This means that there is no placental attachment. Instead the development is exactly like that of an egg, but without the leathery shell.
The shelled egg has a few different layers in addition to the hard (or leathery) calcified part. In fact even the live-bearing snakes that I have had experience with are all born cloaked in an enclosing membrane that I remember to be one of those layers found in a shelled egg. A bigger difference would be the time spent in utero.
My point is that in keeping with my ancient knowledge it all seems to be a matter of degree among the snakes. There doesn’t seem to be any reason that shades of grey could not be present (I would assume that they are.) There may be such a genus in which different species, of different niches and environments, utilize reproductive methods at different ends of the spectrum. With the inter-generic offspring that have already been produced we know that intergrades are possible. Could there be species that could compromise on the method of gestation? If so, I would think that it would favor an ovaviviparous female and an oviparous male.
Waddaya think?
Paul M. Kaczmarczik
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