New Guinea Spotted Tree Monitor at Dresden, 29/08/12

Very nice! Are these common in captivity?

I'd never seen one before this trip, but this was actually the second place I saw them - Dresden being just pipped by Prague Terrarium! Landau Reptilium and Neunkirchen also have them now according to Zootierliste.

I can't say I've seen one before! There are some rather beautiful varanus species in zoos now a days!

Absolutely - the diversity of varanids on display in Europe has increased a fair bit in recent years, happily!