Recently, new marine invertebrate species have been discovered based on combined molecular and morphological differences. Using this dual approach, we found eight species (including four new to science) in one family of polychaete worms from Australian coral reefs; only three were indicated using morphology alone. This study supports the value of using a combined morphological–molecular approach and suggests the number of polychaete species is higher than currently thought.

The first phylogenetic analysis of the spider mite genera Aponychus, Paraponychus and Stylophoronychus is presented. The results indicate a monophyletic clade uniting these genera, although none of them were recovered as monophyletic. We reinstate the tribe Aponychini as the taxon containing those three genera, and highlight the importance of leg chaetotaxy as useful characters for understanding the evolution and relationships within this group.

Almost 50 years after being described by Halffter in 1964, the Mexican Transition Zone is subjected to analysis with the use of modern methods to re-evaluate the biogeographical patterns originally described. Including passalid beetle distribution and using parsimony analysis of endemicity (PAE), null models and ecological niche modeling, three major distribution patterns that reinforce and refine those originally found by Halffter were identified.

The order Opilioacarida is a small, basal group of Acari with a pantropical distribution. The genus Caribeacarus is hypothesised to have originated in mainland South America, with one lineage colonising the Caribbean islands in the Eocene/Oligocene. This pattern does not fit well with established hypotheses, from which it can be inferred that Opilioacarida has a relictual distribution.

Australia’s Alpine region harbours a unique biota, restricted to these peaks by the surrounding lowland environment. Using a molecular phylogeny, we test the evolutionary relationships among species of the endemic grasshopper genus Kosciuscola. Our results support the current taxonomy and provide insights into Kosciuscola population structure, which will be important in assessing the future of these species in the face of future climate change.

Despite being common worldwide, the Neelipleona genus Megalothorax is poorly studied because of minute size and resulting difficulties for identification. The genus is redefined with redescription of the type and description of five new species using a broad set of characters and DNA sequences. This is the most comprehensive work on Neelipleona systematics, providing a strong framework for future studies and shedding light on key characters such as the discovery of trichobothria.