1.) I doubt you'd get interspecies mating if your Shovelnose turns out to be male.
2.) Look here for determining sex:
http://www.caudata.org/cc/articles/sexing.shtml
3.) Pachytriton labiatus are fiercely territorial and will not bat an eye at killing any tankmates. I've got two that I have to keep separated because it'd be cruel to leave them together with the idea that "maybe" they'll be good. Pachys have been known to actively hunt and kill anything that is in their territory. They've also been known to kill members of the same species just for fun.
Pet stores do not generally know how to keep caudates and usually only put them together in tanks long enough to sell them. And do not put it past a pet store clerk to make up a story just to make a sale. And if the pet store clerk who sold you your shovelnose told you he's kept 7-8 species in one tank "for months," I would bet he's lying. If that were the case, the casualty rate in that tank would be enormous.
You are taking a chance at keeping these animals together, especially if you openly admit that your Pachy killed its previous tankmate. Aside from the fact that they are from two different parts of the world, like Mike said, and have different needs, if you blatantly don't care that these species should not be mixed, you probably shouldn't have gotten any newts in the first place. It's extremely irresponsible to keep these two species together, ESPECIALLY if you know that your Pachy has killed before. If you had done your research as you claim you did, you would KNOW that Pachytriton labiatus are one of the more aggressive species.
I would suggest taking both Mike's and Jesper's advice, or you will have casualties. In the short time I had my two Pachys together, when they would "sit" and "swim" next to each other, it meant that one was antagonizing the other. In those two days, I had to pry limbs out of mouths on several occasions.
Just because you've had them together for 3 weeks doesn't mean that they'll magically get along together and be "best friends forever." Sooner or later, like both Mike and Jesper said, one of them WILL kill the other and my money would be on the Pachy.
I doubt you'll take my advice either, but I would suggest you check these links out:
http://www.caudata.org/cc/articles/Mixing_disasters.shtml
http://www.caudata.org/cc/articles/toxin.shtml
http://www.caudata.org/cc/articles/newt_toxins.shtml}
(Message edited by dot on December 15, 2004)
