The ghost shrimp families Callianassidae and Ctenochelidae are a monophyletic taxon of 265 species in 74 nominal genera whose taxonomy is quite unstable. A molecular phylogeny based on half of the species, complemented by morphological treatment, found clades that were interpreted as seven families and 52 genera. Seventeen new genera are required to reflect the molecular phylograms and many existing genera require to be synonymised. The study leads to a more stable classification and taxonomy of this taxon.

Although recent scorpion phylogenomic analyses have shown great discordance with morphological phylogenetic signal, resulting in the reassessment of the higher-level systematics, key taxa have yet to be sampled using genomic data. Here, using transcriptomic data, we evaluate the phylogenetic position of Caraboctonus keyserlingi. Our results show more polyphyletic lineages and support the necessary systematic actions to redress these issues.

Pirate spiders of the family Mimetidae are widely distributed but poorly studied in a phylogenetic context. Here we address their phylogeny, combining morphological and molecular data in a total-evidence approach, reconstruct intergeneric relationships and hypothesise morphological synapomorphies for Mimetidae and its main clades using a taxonomic sample that includes as many representatives of the family as possible.

Assignment of particular species to Unionida has been unstable, particularly for species that were described solely on conchological characters. Unio polystictus Heude, 1877 represents such a species. We investigated the phylogenetic position and generic affinities of U. polystictus using DNA sequence data from five genes (COI, 16S rRNA, 18S rRNA, 28S rRNA and histone H3) and complete mitochondrial genomes. Both the five-gene and mitogenome datasets strongly supported transferring U. polystictus from Margaritiferidae to Unionidae as Aculamprotula polysticta, comb. res.

We present an updated phylogeny of the dorvilleid annelid genus Parougia, with the addition of new DNA sequence data from Pacific Ocean specimens from methane ‘cold’ seeps, hydrothermal vents and a whale-fall. Eight new species are described, and species ranges are documented across up to 6000 km along the eastern Pacific Margin.