The First Fossil Record of the Genus Manica Jurine, 1807 from Late Eocene Baltic Amber and Discussion of the Early Evolution of Myrmicini (Hymenoptera: Formicidae: Myrmicinae)

SIMPLE SUMMARY: In this study, a new fossil ant species from the Baltic amber, †Manica andrannae Zharkov and Dubovikoff, sp. n., is described based on the worker. The main morphological features are studied and illustrated using X-ray micro-computed tomography (µCT), including µCT-based palaeoreconstruction (3D modelling). The newly described taxon is the first fossil species of the genus Manica Jurine, 1807 and represents an important link in understanding the origin and evolution of the genus. Despite the finding of a first fossil species in the Old World, based on the study of a new species and comparing it with other members of the genus, we assume the origin of the genus Manica was North America during the early Eocene (about 50 Ma) and the later distribution of its representatives in Eurasia occurred in the middle of the Eocene or earlier. Relationships with other species of the genus and within tribe Myrmicini are discussed. ABSTRACT: The Holarctic genus Manica Jurine, 1807 are mysterious and primitive ants from the tribe Myrmicini of the subfamily Myrmicinae. The first fossil species of this genus, †Manica andrannae Zharkov and Dubovikoff, sp. n. is described from the Baltic amber (ca. 33.9–37.8 million years ago). X-ray microcomputed tomography (µCT) was used to access morphological features and accurately measure the new species. A straightened and painted 3D model is also proposed as a reconstruction of the worker. The new species differs from all extant species of the genus by the propodeum with a weakly convex dorsum and short, blunt tubercles, and by more angular petiolar node. These features bring it closer to sister genus Myrmica Latreille, 1804. The phylogenetic relationships of the new species with other species of the genus are discussed. Based on the studied morphological features, the species is closest to the species Manica yessensis Azuma, 1955. The early evolution and paleobiogeography of the tribe Myrmicini are discussed. This finding confirms the origin of the genus Manica at least in the Eocene epoch.