Remember the story about Argiope dang, the spider than has been described only a few years before we took the photo? Well, this agamid was described only one year before we took the picture in 2014! A team of German and Russion biologists described this lizard here: Hartmann, Timo & Geissler, Peter & Poyarkov, Nikolay & Ihlow, Flora & Galoyan, Eduard & Rödder, Dennis & Böhme, Wolfgang. (2013). A new species of the genus Calotes Cuvier, 1817 (Squamata: Agamidae) from southern Vietnam. Zootaxa. 3599. 246-260. 10.11646/zootaxa.3599.3.3. From this work we can see that the holotype, meaning the specimen that has been used for the description of this species, was ‘collected’ on the 10th of May 2009 by PG, which should be Peter Geissler. And it was a male. Peter was accompanied by Rike Bach during some trips, and her family name is found in our lizards epithet.
I just found all that out while checking on the ID. Another gem in our picture archive! It lives in one of the most vibrant cities, in Ho Chi Min city. Before its description this lizard was considered to be C. mystaceus., but that one has darker patterns on the back, and a white line where our agamid has a yellow line. In the description is also a comparison, where both species are compared. The scales, and the length of limbs play a role too.
So it is in the same genus as the beautiful C. versicolor, which also lives in Vietnam. Same same, only males show the vibrant color during certain situations ;-). The female of C. bachae though seems to have some blue, too. The genus Calotes seems to have some more colorful species in green, red, blue or even yellow! Hoping for more to find!