Calumma gallus (Günther, 1877) is a small chameleon from eastern Madagascar which remains poorly known. Fieldwork and molecular phylogenetic studies in the last decade have revealed that C. gallus, as currently understood, is a species complex, but available data is still insufficient to comprehensively resolve its taxonomy. In this study, we com­bine mitochondrial DNA sequences and morphological data to draw first taxonomic conclusions. Based on a museomics approach, i.e., archival DNA sequencing of the historical lectotype of C. nasutum we re-define C. nasutum as a species of the C. gallus complex, although it is lacking the elongated rostral appendage usually considered to be diagnostic for the complex. We furthermore describe the populations previously considered under the name C. nasutum as a new species, Calumma hofreiteri sp. n. By analyzing an extended mitochondrial data set of the C. gallus complex, we clarify the genet­ic and phylogeographic variation of these chameleons, with genetic distances of 7.7–14.0% in ND2 and up to 4.1% in 16S rRNA between mitochondrial clades within the complex. We assign the name C. gallus sensu stricto to a mitochondrial clade containing specimens with distinctly elongated and serrated rostral appendages and describe the northernmost and phylogenetically most divergent populations of the complex as a new species, Calumma pinocchio sp. n., based on their ge­netic divergence and comparatively smooth-edged elongated rostral appendage. We discuss the rapid evolution of rostral appendages in this species complex and highlight the need for expanded collection and in-depth phylogenomic analysis to fully clarify species limits and evolution of these chameleons.