Spatial phylogenomics of acrobat ants in Madagascar—mountains function as cradles for recent diversity and endemism

<p><span><span><span><span><span><span><span><span><span><span><span><b>Aim: </b></span></span></span></span></span></span></span></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span>A crucial step to protecting biodiversity is assessing species diversity and endemism. We delineate<b> </b>spatial patterns of diversity in Malagasy ants on a phylogenetic and taxonomic level to identify centers of diversity and endemism, and evaluate the 'museum vs cradle' hypothesis with regard to ant endemism.</span></span></span></span></span></span></span></span></span></span></span></p> <p><span><span><span><span><span><span><span><span><span><span><span><b>Location: </b></span></span></span></span></span></span></span></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span>Madagascar</span></span></span></span></span></span></span></span></span></span></span></p> <p><span><span><span><span><span><span><span><span><span><span><span><b>Taxon: </b></span></span></span></span></span></span></span></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span>Ants, genus <i>Crematogaster.</i></span></span></span></span></span></span></span></span></span></span></span></p> <p><span><span><span><span><span><span><span><span><span><span><span><b>Methods: </b></span></span></span></span></span></span></span></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span>We estimated distribution models for 33 <i>Crematogaster</i> species and generated a phylogeny based on ultraconserved elements. We calculated species richness (SR), phylogenetic diversity (PD), weighted (WE), phylogenetic endemism(PE), randomized phylogenetic diversity (PD-sig), and relative phylogenetic diversity (RPD) and endemism (RPE). Categorical analyses of neo- and paleo-endemism (CANAPE) and the phylo-jaccard index were used to delineate centers of neo- and paleo-endemism. We correlated these measures with elevation metrics to investigate the role of mountains in generating ant endemism.</span></span></span></span></span></span></span></span></span></span></span></p> <p><span><span><span><span><span><span><span><span><span><span><span><b>Results: </b></span></span></span></span></span></span></span></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span>We found extensive phylogenetic clustering (significantly low PD-sig) and short branches (low RPD) at higher elevations in central and south-central to southern Madagascar. In contrast, phylogenetic overdispersion (significantly high PD-sig) and long branches (high RPD) predominate at lower elevations in eastern humid and northern western dry forests. CANAPE and phylo-jaccard estimated five centers of endemism, whereby neo- and mixed endemism were significantly correlated with higher elevations, and paleo-endemism with lower elevations. </span></span></span></span></span></span></span></span></span></span></span></p> <p><span><span><span><span><span><span><span><span><span><span><span><b>Main Conclusions: </b></span></span></span></span></span></span></span></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span>Centers of ant endemism are located in western dry and humid forests of northern Madagascar, eastern humid forests, and in the southern Central Highland region. </span></span></span></span></span></span></span></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span>Mountainous areas appear to be cradles of recent diversification for acrobat ants, whereas lower elevations may be regarded as centers of paleo-endemism and thus museums for relict lineages. Species diversification among acrobat ants may have coincided with the arrival of a new biome in the central highlands of Madagascar. </span></span></span></span></span></span></span></span></span></span></span></p>