Hi Wim,
Wonderful gesneriads you have there. In particular, I have always been an admirer of Asteranthera. I think that sadly, I have to enjoy them vicariously through other hobbyists.
Other than their temperature requirements, are they suited for typical terrarium life?
Thanks for sharing your photo.
Kelli,
This Neomortonia does well on most substrates for me, although the most rampant growth occurs on New Zealand sphagnum. Damp, but well drained substrate. Humid conditions, but not placed in the line of any spray-heads. For growth, they seem to be able to handle a fairly wide range of temperatures, but I would establish it with temps in the low to mid 70's if possible. Lighting also doesn't seem terribly important, but brighter light produces nice color in the leaves. If you are trying to propagate your plant, cuttings of about 3" works well.
Good luck.