Colostethus Tadpoles
Hi.
'Fraid I don't know anyone working with the genus in captivity, but I couldn't agree with you more about the tadpole morphology. Some of Caldwell's Colosethus tadpole descriptions have been wild! I would love to see more documentation of the tadpoles coming out of the hobby- Tor Linbo's photo series have been great, but precious little is else is available.
This is an area in which Dendro hobbists could make a real difference to the science side of things- we have very little information on tadpoles in general. Within the dendrobatids, even species commonly kept in captivity, the tadpoles are poorly, if at all, described.
Someone with a good camera, a copy of the Gosner stages, and a lot of patience would be very much appreciated.