The West-Palearctic region is a diversity hotspot for the ant genus Aphaenogaster. Species in this region are characterized by high morphological variation, which has led to their subdivisioninto different infrageneric groups. The very first classification in three subgenera, dated 1915, was gradually replaced by eight species-groups. To probe the evolutionary consistency of these species-groups, we sequenced 46 species from all eight species-groups and biogeographic sectors of the region, using one mitochondrial (COI) and six nuclear markers (EPICs), and interpreted the results by integrating qualitative morphology. Our results demonstrate the non-monophyly of all formerly recognized subgenera and species-groups, except for the crocea group. We use the phylogeny and morphological characters to propose a new classification of six monophyletic species-groups (crocea, gibbosa, graeca, pallida, sardoa, subterranea). The pallida, subterranea and sardoa (formerly testaceopilosa) groups attain monophyletic status by reassigning a few taxa. The gibbosa group is to be considered exclusively Western-Mediterranean until further assessments of similar Eastern species. The new graeca group is established by including former members of the splendida and subterranea groups, while the polyphyletic cecconii, obsidiana, and splendida groups are dismissed. Notably, the first is not part of the tropical Deromyrma clade as previously thought, while at least two independent clades which require further investigation are composed of species from both the cecconii and splendida groups, suggesting repeated morphological convergences based on similar ecological adaptations. Finally, A. cardenai is confirmed to be a significantly divergent lineage. In addition, three Aphaenogaster species are moved to different genera: Messor asmaae (Sharaf, 2018) comb. nov., Messor isekram (Bernard, 1977) comb. nov., and Pheidole sarae (Sharaf, 2018) comb. nov. Further studies should address the evolutionary relationships between the clades recovered in this study.

Temnothorax (Myrmicinae, Crematogastrini) is one of the most diverse Holarctic ant genera, and new taxonomic advancements are still frequent worldwide. The Mediterranean region, a global biodiversity hotspot characterized by a complex geographic history, is home to a substantial portion of its described diversity. Sicily is the region’s largest island and, as ongoing investigations are revealing, it is inhabited by a long-overlooked but highly diverse ant fauna that combines multiple biogeographic influences. We combined qualitative and quantitative morphology of multiple castes with phylogenomic analysis based on ultra-conserved elements (UCEs) to describe four species of Temnothorax endemic to Sicily and the neighboring Maltese Islands (Sicilian Channel). Three of these species, T. marae Alicata, Schifani & Prebus sp. nov., T. poldii Alicata, Schifani & Prebus sp. nov. and T. vivianoi Schifani, Alicata & Prebus sp. nov., are new to science, while a redescription clarifies the identity of T. lagrecai (Baroni Urbani, 1964). These descriptions highlight the current difficulties of delimiting monophyletic Temnothorax species groups based on morphological characters. The intra-insular endemicity patterns we revealed highlight the importance of Mediterranean paleogeography to contemporary ant diversity and distribution in the region.

More than 100 years ago, the Italian myrmecologist Carlo Emery described two endemic Sicilian ants: Aphaenogaster sicula Emery, 1908, which he originally considered a subspecies of A. crocea André, 1881, and A. fiorii Emery, 1915 stat. nov., which he believed was a subspecies of A. gibbosa (Latreille, 1798). Males of the two species and the queen of A. fiorii were never described. The scarcity of information contained in the original description led to several misunderstandings by subsequent authors: for example, A. sicula was later elevated to species-rank on the basis of misidentified material of A. fiorii stat. nov. We redescribe the two species, adding the descriptions of their missing castes and designating their lectotypes. We also describe a third related species of the genus: A. trinacriae sp. nov. from Sicily. The ecology and distribution of the three are illustrated. Their relationship with the other congeneric species of the Mediterranean basin is discussed considering the morphology of all three castes, with attention to the often-overlooked males. Despite the fact that A. fiorii and A. sicula were lately believed to be close relatives of A. subterranea (Latreille, 1798), the morphological elements available suggest that they probably belong to a separate, hitherto unrecognized clade from the Maghreb (North-Western Africa), together with A. trinacriae sp. nov.

Formica clara is an ant species that was historically confused with other congeneric species such as F. rufibarbis until recent taxonomic developments. Due to such misunderstanding, while F. clara is known to occur across a very large Eurasian range, its actual distribution in the Mediterranean is often scarcely known. The distribution of F. clara and F. rufibarbis in Italy is remarkably obscure since almost all records, which spanned across the whole Italian peninsula and Sardinia, were published between 1834 and 1969, at times when the two species were treated as a single taxon. The few modern records of the species testify the presence of F. rufibarbis in the Alps, and F. clara in the Alps, the Po Plain and Sardinia. Here we present some new distributional data on the two species, extending the geographic range of F. rufibarbis south to the Northern Apennines (225 km) and that of F. clara throughout the Italian Peninsula south to Sicily (900 km). These results significantly change the previous understanding of F. rufibarbis as a widespread species while suggesting F. clara to be a common mountain species through the whole Apennines. Further investigations will be needed to verify whether F. rufibarbis occurs farther south.

The ant genus Myrmecina , whose diversity is mostly concentrated in SE-Asia and Oceania, counts four W-Palearctic species. The extremely euryecious and well-studied Myrmecina graminicola occurs from Iberia to the Caucasus and from the Maghreb to Scandinavia, while three little-known species ( M. atlantis , M. melonii and M. sicula ) coexist with M. graminicola in their narrow Maghrebian, Sardinian and Sicilian ranges, respectively. Myrmecina sicula has been described about 140 years ago from a single site and two specimens only. Their unique morphology suggested the validity of this taxon ever since, but no additional specimens were found in the following century. We present the results of decades of sampling efforts across Sicily, resulting in the collection of M. graminicola from 70 sites and M. sicula from 13 sites. We confirm M. sicula unique morphological identity and report on the marked distributional and ecological differences between the two species. Myrmecina graminicola is widespread and inhabits diverse, mainly forested habitats from lowland to high mountain sites, while M. sicula was found in a very narrow region of old carbonate platform between NW-Sicily and the Egadi Islands, mostly in sparsely vegetated sites at mid to low-altitude. Reviewing their common morphological and biogeographic traits, we propose to consider M. atlantis , M. melonii and M. sicula as a distinct M. sicula complex, whose identity and history deserves further investigation through molecular analyses.

Temnothorax unifasciatus (Latreille, 1798) is a widely distributed pan‐European species from the Iberian Peninsula to the Caucasus. This taxon's relatively high morphological variability prompts the taxonomists of earlier times and today to mention the morphologically different elements at specific or subspecific ranks. This paper aims to understand the population structure and genetic diversity within this lineage via integrative taxonomy, incorporating molecular phylogenetics, species delimitation analyses and multivariate analyses of continuous morphometric data from across the geographic range of the T. unifasciatus complex. Phylogenetic analyses yielded incongruent trees. The genealogical diversity index (gdi) and the confirmatory analyses on morphological data found only weak, ambiguous delimitations within the unifasciatus complex. The most highly supported scenario splits T. brackoi from the remaining unifasciatus complex with ambiguous support (gdi = 0.56). This scenario is supported by multivariate morphometry with 100% accuracy in classification success. Instead, our results suggest complex morphological and genetic population structuring within the broad range of T. unifasciatus. Therefore, we confirm the validity of two species, T. brackoi Salata & Borowiec, 2019 and T. unifasciatus (Latreille, 1798), and propose five new junior synonymies, T. cordieri (Bondroit, 1918) syn. nov., T. tauricus (Ruzsky, 1902) syn. nov., T. berlandi (Bondroit, 1918) syn. nov., T. unifasciatus staegeri (Bondroit, 1918) syn. nov., T. tuberum ciscaucasicus (Arnol'di, 1977) syn. nov. with the latter. To achieve maximal taxonomic stability, we designated a lectotype for Temnothorax unifasciatus (Latreille, 1798).