I have exchanged with Brent Brock this morning from TWI, and here's what he had to say about the project:

"The gottlebei program is still active but seriously stalled because we haven’t been able to obtain enough specimens to attempt any breeding. (...) Very briefly, I can tell you that a couple of zoos have been successful in getting frogs to spawn without hormones and producing tadpoles. But tadpole mortality has been 100% (unless there have been successes I’m unaware of in the last year).(...) But as I recall, a rain chamber was used to stimulate breeding. In nature the species appears to respond to floods."

Brent will drop by to add more on this.

Eric