|Stumpffia davidattenboroughi. Photo credit G. M. Rosa
The genus Stumpffia Boettger, 1881 was first described based on the species Stumpffia psologlossa a small frog from Nosy Be Island, Benavony, and Manongarivo on the adjacent mainland in north-western Madagascar. This appears to be a lowland species ranging as high as 700 m asl. It lives in the leaf-litter of both primary and degraded rainforest, and in coffee plantations. Reproduction uses non-feeding larval developing in terrestrial nests that are guarded by the male. By 2015 the microhylid genus contained 15 species.
In a new paper, Rakotoarison et al. (2017) revise the genus on the basis of a combination of molecular, bioacoustic, and morphological data and describe 26 new species that are all genetically divergent, almost all of them with high pairwise genetic divergences > 4% p-distance in a segment of the mitochondrial 16S rRNA gene and concordant differentiation in a segment of the nuclear Rag-1 gene.
The majority of the new species can also be distinguished by the structure of their advertisement calls (where bioacoustic data are available), and in most comparisons, the species can also be distinguished morphologically.
Despite the large number of Stumpffia species the authors identify several additional candidate species with currently insufficient data to warrant formal description, and they highlight that some species such as S. analanjirofo, S. gimmeli, S. kibomena, S. madagascariensis, S. roseifemoralis and S. obscoena are composed of two or more deep mitochondrial lineages that might also turn out to be distinct taxa after in-depth study. They confirm Stumpffia as a genus of highly microendemic frogs with many species apparently restricted to very small ranges, and provide evidence that two of the new species (S. achillei and S. davidattenboroughi) do not construct foam nests but lay their eggs in wet places in the leaf litter, or in cavities such as empty snail shells. The authors proposed a conservation status for all the described species according to IUCN Red List Criteria, and discuss several problems applying these criteria to such microendemic and poorly known frogs. Of the 41 species of Stumpffia, only seven appear to be wide-ranging, non-microedemics.
Rakotoarison A, Scherz MD, Glaw F, Köhler J, Andreone F, Franzen M, Glos J, Hawlitschek O, Jono T, Mori A, Ndriantsoa SH. 2017. Describing the smaller majority: integrative taxonomy reveals twenty-six new species of tiny microhylid frogs (genus Stumpffia) from Madagascar. Vertebrate Zoology 67(3): 271–398.