Neglected for almost a century: rediscovering and redescribing the enigmatic endemic species Messor fodorii Röszler, 1942 stat. nov. (Hymenoptera: Formicidae) from Chios Island (Greece)
The genus Messor Forel, 1890 currently comprises 171 valid species and subspecies, with highest diversity in the Mediterranean and Central Asia. Greece hosts at least 16 species, although the taxonomic status of some needs to be further investigated. Amongst these, six species are island endemics, either restricted to a single Aegean island or distributed across several islands in the archipelago. Despite recent studies on the harvester ants of Greece, the case of Messor antennatus fodorii Röszler, 1942, remained unresolved amongst Greek representatives. This enigmatic harvester ant was first collected almost a century ago, in 1935, from Chios Island, situated in the northeastern part of the Aegean Sea. The lack of both a type and additional material has led to its exclusion from checklists and identification keys, leaving its status as uncertain. From April 24th to May 5th 2025, we conducted field surveys in Chios, Oinousses and Psara islands to investigate the presence and taxonomic status of M. antennatus fodorii. Upon investigation, the harvester ant is raised to the species level Messor fodorii Röszler, 1942 stat. nov., designating a neotype, providing a re-description, a morphometric comparison of species in the M. hellenius complex, ecological notes and an updated identification key to Greek representatives of the Messor hellenius species complex.