As a result of recent collecting efforts and older unpublished data of one of us (AA), 32 ant species (including 2 morphospecies) new to the island of Sicily (Italy) were discovered. Seven of these taxa represent unequivocally exotic entities, whose discovery marks a decisive increase of this component in the local fauna. Among these, two forms of Nylanderia EMERY, 1906 are treated as morphospecies because of the problematic taxonomy of the genus. Six taxa among the discovered species are entirely new to the myrmecofauna of Italy. Finally, Tetramorium indocile SANTSCHI, 1927 is reported for the first time as a host for the social parasite Strongylognathus testaceus (SCHENCK, 1852). The state of the art of the Sicilian myrmecofauna, now counting about 150 species, is commented on.

Abstract 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.

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.

The ant fauna of Sicily, the largest island in the Mediterranean basin, has been significantly overlooked over the time. Drafting a reliable Sicilian ant checklist requires extensive field surveys, a careful review of the literature and of museum specimens, as well as the taxonomic investigation of some problematic issues. As a part of these ongoing efforts, we present our results on the presence or absence of 25 species. By analyzing specimens collected during the last 35 years across the island and reviewing old records in the light of present-day taxonomy, we provide evidence of the presence of 9 species (Camponotus ruber, Lasius myops, L. platythorax, Plagiolepis schmitzii, Ponera testacea, Solenopsis orbula, Temnothorax clypeatus, T. nylanderi, and T. ravouxi), while suggesting the absence of 19 others (Camponotus ligniperda, C. sicheli, C. spissinodis, Formica lugubris, Lasius alienus, L. flavus, L. niger, L. paralienus, Messor minor, M. wasmanni, Monomorium monomorium, Myrmica scabrinodis, M. spinosior, Nylanderia sp. 2 sensu Schifani & Alicata 2018, Solenopsis fugax, Temnothorax luteus, T. tuberum, Tetramorium caespitum, and T. indocile). Similar studies are necessary across Italy, as a significant portion of the existing ant records is outdated due to the evolved taxonomic framework.

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.