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Global biodiversity is under accelerating threats, and species are succumbing to extinction before being described. Madagascar's biota represents an extreme example of this scenario, with the added complication that much of its endemic biodiversity is cryptic. Here we illustrate best practices for clarifying cryptic diversification processes by presenting an integrative framework that leverages multiple lines of evidence and taxon-informed cut-offs for species delimitation, while placing special emphasis on identifying patterns of isolation by distance. We systematically apply this framework to an entire taxonomically controversial primate clade, the mouse lemurs (genus Microcebus, family Cheirogaleidae). We demonstrate that species diversity has been overestimated primarily due to the interpretation of geographic variation as speciation, potentially biasing inference of the underlying processes of evolutionary diversification. Following a revised classification, we find that crypsis within the genus is best explained by a model of morphological stasis imposed by stabilizing selection and a neutral process of niche diversification. Finally, by clarifying species limits and defining evolutionarily significant units, we provide new conservation priorities, bridging fundamental and applied objectives in a generalizable framework., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The number of species of miniaturized chameleons of the genus Brookesia, subgenus Evoluticauda, known to science has witnessed a dramatic increase over the past 15 years, due to the discovery of multiple microendemic species of very strong genetic divergence. So far, no described Evoluticauda species are known from the littoral forest of Madagascar's east coast, one of the most threatened habitat types of the island. Here, we report on the discovery of a new species of Evoluticauda occurring in the littoral forest at Ankanin'ny Nofy, a touristic site at about sea level and close to Vohibola forest where probably the same species occurs. The new species, Brookesia nofy sp. nov., is sister to B. ramanantsoai which occurs in mid-altitude and highland forests (800-1300 m a.s.l.) at a similar latitude of eastern Madagascar, but differs from this species by an enormous genetic divergence in both mitochondrial and nuclear genes (8.1-9.4% uncorrected pairwise distance in the 16S rRNA gene, 1.8-2.5% in c-mos), a relatively shorter tail, a different arrangement of cephalic ridges, and probably smaller body size and relatively larger head. The discovery of B. nofy sp. nov. emphasizes the importance of conserving Madagascar's last remaining fragments of littoral forest.