Male horn lack of allometry may be tied to food relocation behaviour in lifting dung beetles (Coleoptera, Scarabaeidae, Eucraniini)

The small dung beetle tribe Eucraniini includes extremely specialized species that have been defined as “lifters” according to their food relocation behaviour. They are characterized by the presence of well-developed expansions on the head and pronotum, which can be included in the large and varied group of horns, whose presence is usually related to complex reproductive tactics. In this study, two closely related species, Anomiopsoides cavifrons and A. heteroclyta, were examined employing traditional and geometric morphometrics to test whether the Eucraniini has polymorphic males that might exhibit different reproductive tactics, as in the sister tribe Phanaeini, for which a male trimorphism was demonstrated. If also present in Eucraniini polyphenism could be considered a plesiomorphy common to the two clades. The inter- and intraspecific shape variation and object symmetry of the head and the scaling relationships between body size and traits were evaluated. Marked interspecific and small intraspecific differences in shape variation, high symmetry, and similar isometric growth patterns were shown in both species. The hypothesis of male polymorphism in Anomiopsoides was thus rejected. Instead, the results supported the alternative hypothesis that Eucraniini lacks male polymorphism, perhaps due to functional constraints affecting the shape of the structures involved in their peculiar food relocating behaviour

Phylogenetic and biogeographical review of the Drepanocerina (Coleoptera: Scarabaeidae: Oniticellini)

A phylogenetic analysis of Drepanocerina based on 81 morphological characters was conducted using various analytical approaches (Maximum Parsimony, New Technology Search, Bayesian Inference, and Phylogenetic Networks Analysis). Twelve lineages ranked at the generic level were resolved, with full congruency among the four analytical methods. Results allowed to propose two new genera, which are herein described as Paraixodina gen. nov. and Epidrepanus gen. nov. In addition, the previously unknown Eodrepanus integriceps and Sinodrepanus similis females were identified and described. A biogeographic analysis was performed based on 14 geographic macro-areas, partitioning the subtribe and outgroup distributional ranges. Based on the inferred phylogeny and biogeography, an ancestral distribution and radiation scenario from the Central East Africa macroarea (Afrotropical Region) was proposed. The biogeographic implications of past and present-day relationships within Drepanocerina was discussed