Systematic biologists must choose how best to represent discoveries of novel new species within the taxonomic framework of the tree of life. In this contribution, two highly distinctive Australian carabid beetle species are described and placed in new genera based on their phylogenetic relationships within a circum-Antarctically distributed lineage. The synthesis of morphological analysis, molecular phylogenetics, biogeography and earth history produces concise hypotheses concerning the evolutionary history of this austral-disjunct group. This process demonstrates the power of phylogenetic analysis to illuminate the significance of newly discovered biodiversity.

Pseudoscorpions of the genus Garypus are restricted to coastal habitats around the world. Our review of the Australasian fauna using morphology and sequence data reveals evidence for 10 species, nine of which are newly described, from northern Australia and Indonesia. Available mitochondrial sequence data finds COI divergence levels of 7–19% between species.

Several closely related species of Paralimnadia (Crustacea, Branchiopoda, Spinicaudata) inhabit small temporary habitats throughout the Great Dividing Range in eastern Australia. By combining analyses of mitochondrial COI with double-digest restriction-site associated DNA (ddRAD) data, we studied the species diversity and genetic diversity of this group of mountain-dwelling branchiopods. Our data suggest that the species diversity of Paralimnadia in the Great Dividing Range is much higher than currently appreciated.

Echiura (spoon worms) are derived annelids that have an unsegmented sausage-shaped body with a highly extensible proboscis; currently they comprise five families (Echiuridae, Urechidae, Thalassematidae, Bonelliidae and Ikedidae). Here, we reinvestigate the echiuran familial relationships using an expanded dataset with more taxa and genes. In contrast to previous results, our analyses strongly suggest that the giant echiuran family Ikedidae is nested within Bonelliidae. Furthermore, considering that recent phylogenetic studies have consistently recovered Echiura as the sister group to Capitelliidae within Annelida, we drop the rank of the echiuran clade to family-level and propose a new classification.