In this study we present the first taxonomic revision of the ant genus Stigmatomma in the Malagasy biogeographic region, redescribe the previously known S. besucheti Baroni-Urbani, and describe seven new species to science (S. bolabola sp. n., S. irayhady sp. n., S. janovitsika sp. n., S. liebe sp. n., S. roahady sp. n., S. sakalava sp. n., and S. tsyhady sp. n.). The revision is based on the worker caste, but we provide brief descriptions of gynes and males for some species. Species descriptions, diagnosis, character discussion, identiﬁcation key, and glossary are illustrated with 360 high-quality montage and SEM images. The distribution of Stigmatomma species in Madagascar are mapped and discussed within the context of the island’s biomes and ecoregions. We also discuss how some morphometric variables describe the diﬀerences among the species in the bioregion. Open science is supported by providing access to R scripts, raw measurement data, and all specimen data used. All specimens used in this study were given unique identifies, and holotypes were imaged. Specimens and images are made accessible on AntWeb.org.
R script for clustering specimens based on measurement data
Script for performing UPGMA hierarchical cluster analysis on the R platform.
R script for clustering.pdf
R script for Principal Component Analysis (PCA): specimens on a morphometric ordination space
Script for performing Principal Component Analysis (PCA) on the R platform.
R script for PCA.pdf
Script for mapping the distribution of Stigmatomma species in Madagascar and Seychelles
R code for making species distribution maps. Note: Our maps use the ecoregion outlines of Madagascar, which were based on the vector data disclosed by the Terrestrial Ecoregions of the World (available at the WWF website). However, the original outlines were slightly mismatching the relief of Madagascar. To solve this, we combined the original ecoregion data with data from the Remaining Primary Vegetation of Madagascar (available at the Kew Royal Botanic Gardens website), which has more natural outlines.
Linear morphometry of Stigmatomma species in the Malagasy bioregion – raw data set of measurements and indices
Measurements were taken on a Leica MZ APO stereomicroscope, rounded to the nearest 0.01 mm. Head length (HL): in fullface view, straight line from the anterior clypeal margin to the midpoint of a straight imaginary line connecting posterior corners of the head.
Head width (HW): maximum width of the head, including eyes when present.
Head width 2 (HW2): width of the head immediately posterior to the posterolateral margin of the clypeus.
Scape length (SL): length of the scape (first antennal segment), excluding its basal constriction or neck and condyle.
Mandibular length (ML): outer length of the mandible.
Weber’s length of mesosoma (WL): diagonal length of the mesosoma in profile, from base of anterior slope of pronotum to metapleural lobe.
Propodeal posterior width (PPW): width of posterior margin of propodeal dorsal face, in dorsal view.
Petiolar length (PtL): maximum length of petiole in dorsal view.
Petiolar width (PtW): maximum width of petiole in dorsal view.
Cephalic index (CI): HW/HL ×100.
Scape index (SI): SL/HL ×100.
Mandibular index (MI): ML/HL ×100.
Petiolar index (PtI): PtL/PtW ×100.