Microendemic Sentinel of Montagne d’Ambre: Calumma amber

Calumma amber Raxworthy & Nussbaum, 2006 is a montane chameleon confined to the humid evergreen forests of Montagne d'Ambre in Antsiranana Province. Originally considered a population of C. brevicorne, it was described as distinct based on occipital lobe morphology and hemipenial characters. Adults exhibit robust cranial ornamentation, with males showing pronounced occipital lobes and casque development. The species is strictly arboreal, occupying mid‑ to upper canopy strata in cool, moist montane habitats. Its distribution is microendemic, with an extent of occurrence limited to the northern Diana Region. The IUCN Red List categorizes C. amber as Near Threatened, citing habitat loss from agricultural expansion, logging, and localized extraction pressures. Although Montagne d'Ambre National Park affords protection, surrounding forest fragments remain vulnerable. For herpetologists, C. amber exemplifies the taxonomic refinement of Malagasy chameleons: cryptic diversity revealed through detailed morphological study, and conservation urgency tied to narrow ecological specialization.