Nemognathinae is the most widespread Meloidae subfamily, with ~600 species, among which are the only blister beetle species that occur in Oceania. A comprehensive molecular phylogeny for the group is lacking. We investigated the history of this subfamily with a fossil-calibrated molecular approach, revealing the presence of a new tribe, the polyphyly of a few genera and an Eocene origin in the Old World. This work represents the first molecular phylogeny of Nemognathinae and contributes to revealing the evolutionary history of the Meloidae.

Males of the spider genus Mecolaesthus are characterised by a dorsally ‘inflated’ prosoma. We describe the first representatives from Ecuador and place them in a phylogenetic context. First micro-computed tomography data of the male prosoma ‘inflation’ show that itis tightly packed with muscles inserted at the leg coxae. Male leg length is negatively correlated with body size, suggesting that male-male fights in Mecolaesthus rely on powerful leg movements. We document the fourth known case of structural genital asymmetry in Pholcidae.

Exploration of understudied areas is often an important way to discover new species diversity. Guangxi is part of the Chinese portion of the Indo-Burma biodiversity hotspot housing many endemic freshwater species but regional studies of freshwater mussel diversity are scarce. Here, we report a new endemic freshwater mussel species from Guangxi: Postolata guangxiensis gen. nov., sp. nov. Phylogenetic analyses based on the three-gene data and complete mitochondrial genomes supported the validity of the classification status. Our results provide new insights into the phylogeny and conservation of poorly known freshwater mussels.