Mantella baroni is a small frog, with adults measuring 22-30 mm in snout-vent length. The head, dorsum, and flanks are solid black. A yellowish rostral stripe is apparent, generally ending past the eye. The front limb and femur are yellow to greenish in appearance, with this coloration continuing up the flanks into a large, rounded flank blotch. These flank blotches will sometimes expand dorsally across the back and connect to the opposite side blotch, resulting in a more yellow dorsum (this is most often seen in M. baroni from the Andringitra region). Hindlimbs (tibia, tarsus, and foot) are orange with irregular black stripes. There are no flashmarks on the lower hindlimbs, in contrast to those of M. madagascariensis. The venter, throat, and limbs are black and marked with a few yellow to greenish, rarely blue blotches. The throat has one circular marking, but may be all black. The iris is black (Glaw and Vences 2007).
Mantella baroni was first described by Boulenger (1888). It is a member of the M. cowani species group (Goodman and Benstead 2003). There is a report of hybridization with M. cowani in the wild, at a locality near Antoetra (Andreone et al. 2005).
- Andriantsiferana, M., Andriamaharavo, N. R., Razafindrabe, C. R., Harisoa, C., Rasendra, P., Garraffo, M., Spande, T., and Daly, J. (2006). New lipophilic alkaloids from Mantella frogs collected in Madagascar. 11th NAPRECA Symposium Book of Proceedings, Antananarivo, Madagascar.
- Boulenger, G. A. (1888). ''Descriptions of new reptiles and batrachians from Madagascar.'' Annals and Magazine of Natural History, series 6, 1, 101-107.
- Clark, V. C., Rakotomalala, V., Ramilijaona, O., Abrell, L., and Fisher, B. L. (2006). ''Individual variation in alkaloid content of poison frogs of Madagascar (Mantella; Mantellidae).'' Journal of Chemical Ecology, 32, 2219-2233.
- Clark, V. C., Raxworthy, C. J., Rakotomalala, V., Sierwald, P., and Fisher, B. L. (2005). ''Convergent evolution of chemical defense in poison frogs and arthropod prey between Madagascar and the Neotropics.'' Proceedings of the National Academy of Sciences, 102(33), 11617-11622.
- Daly, J. W., Garraffo, M., Spande, T. F., Giddings, L., Saporito, R. A., Vieites, D. R., and Vences, M. (2008). ''Individual and geographic variation of skin alkaloids in three species of Madagascan poison frogs (Mantella).'' Journal of Chemical Ecology, 34, 252-279.
- Glaw, F., and Vences, M. (2007). Field Guide to the Amphibians and Reptiles of Madagascar. Third Edition. Vences and Glaw Verlag, Köln.
- Goodman, S. M., and Benstead, J. P. (2003). The Natural History of Madagascar. University of Chicago Press, Chicago.
- IUCN (2008). 2008 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 11 December 2008.
- Odierna, G., Vences, M., Aprea, G., Lötters, S., and Andreone, F. (2001). ''Chromosome data for Malagasy poison frogs (Amphibia: Ranidae: Mantella) and their bearing on taxonomy and phylogeny.'' Zoological Science, 18, 505-514.