DOI: 10.3897/asp.81.e104810

Authors: Zachary H. Griebenow, Adrian Richter, Thomas van de Kamp, Evan P. Economo, Ziv E. Lieberman

Abstract: The male genitalia of the Insecta are famed for structural and functional diversity. Variation in this anatomical region shows ample phylogenetic signal, and this variation has proven indispensable for classification across the insects at multiple taxonomic ranks. However, in the ants (Hymenoptera: Formicidae) the male genital phenotype is ancillary to the morphology of the worker caste for systematic purposes. Ants of the enigmatic subfamily Leptanillinae are an exception, as males are easier to collect than workers. Ongoing systematic revision of the Leptanillinae must therefore rely upon the male phenotype – particularly the spectacular morphological profusion of the male genitalia. To thoroughly illuminate this anatomical region and aid comparative morphological research on ant male genitalia, we present a comparative morphological study of the male genitalia in nine exemplar lineages spanning the Leptanillinae, plus three outgroups representing other major clades of the Formicidae. We use micro-computed tomography (micro-CT) to generate 3D volumetric reconstructions of male genital skeletomusculature in these specimens. Our descriptions use new muscular terminology compatible with topographic main-group systems for the rest of the pterygote soma, and applicable to all Hymenoptera. We find that male genitalia in the Leptanillinae show an overall trend towards skeletomuscular simplification, with muscular reduction in some cases being unprecedented in ants, or even hymenopterans in general. In several lineages of the Leptanillinae we describe derivations of the male genitalia that are bizarre and unparalleled among the Hymenoptera. We conclude by discussing the functional implications of the often-extreme morphologies here observed.

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DOI: 10.3897/asp.80.e84428

Authors: Enrico Schifani, Antonio Alicata, Mattia Menchetti, Lech Borowiec, Brian L. Fisher, Celal Karaman, Kadri Kiran, Wala Oueslati, Sebastian Salata, Rumsaïs Blatrix

Abstract: 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.

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