Hi Willi

Thanks a lot for your response. We also frequently detect dark colored tiny frogs/toads of more or less similar size perfectly camouflaged in dark and moist litter of  shady trees in Bangalore, India. We are not yet aware of the taxonomic status of such tiny vertebrates.

Thanks.

Best

Syed

The small paedomorphic goby Schindleria brevipinguis reaches a maximum size of 8.4 mm, but is very thin and has much less body mass than a frog.

Watson, W. and H. J., Jr. Walker 2004

The world's smallest vertebrate, Schindleria brevipinguis, a new paedomorphic species in the family Schindleriidae (Perciformes: Gobioidei). Records of the Australian Museum v. 56 (no. 2): 139-142.

http://australianmuseum.net.au/uploads/journals/18003/1429.pdf

Dear Ronald

Thank you for this important reference.Since the question relates to size and not mass, the frog/toad as of now qualifies to be the smallest living vertebrate.

Syed