Molecular phylogeny has proven invaluable in identifying species in the mostly tropical centipede family Scolopendridae. Revision of SE Asian species of the scolopendrid genera Rhysida and Alluropus is based on classical external morphological characters for clades underpinned by multi-gene trees. The previously enigmatic Alluropus is found to be widespread throughout SE Asia, the supposedly diagnostic characters of its type species reflecting sexual variation.

We present an updated phylogeny of the annelid clade Hesionidae, with the addition of new DNA sequence data from deep water hesionids, mainly from methane ‘cold’ seeps off the Pacific coast of Costa Rica. Four new species are described and species ranges are documented across up to 6000 km. The new phylogeny allows for further revision of the classification of Hesionidae.

Although speciation is most often explained as the result of divergent selection in geographically isolated populations, alternative evolutionary scenarios have been documented by scientists. We describe how two sibling spiders may have originated via ecological differentiation in two contiguous and interconnected subterranean habitats with different sizes of void spaces. Our data demonstrate that habitat size may drive species differentiation within the subterranean realm by minimising intraspecific competition through niche partitioning, and provide further evidence of the importance of space heterogeneity as an evolutionary driver.

Molecular phylogenetics sometimes is inconsistent with morphological data, notably within the phylum Cnidaria. An integrative approach to a case of incongruence in hydrozoans results in improved systematics, with the designation of a new genus with divergent origin, endemic to the eastern and western coasts of the North Pacific Ocean. This suggests that incongruence in molecular and morphological inferences may be of great systematic significance.

The Mediterranean Sea is home to a diverse assemblage of black corals including some of the most early described antipatharian species. A new molecular analysis reveals that the species on which the genus Antipathes, the family Antipathidae, and the order Antipatharia are based is an imposter! Thus, we are recommending a revision of the classification scheme that has been in place since 1766 to reflect this unexpected finding.

The first molecular phylogeny of termite including all termite families is presented. Stylotermitidae is the sister to all remaining Neoisoptera. This work provides foundation knowledge for following studies on termite developmental pathways and pheromone communication.

A thorough exploration of morphology supported by molecular species delimitation approaches offers an efficient way to discover new differential characters, even in traditionally neglected groups with difficult taxonomy. We provide a first detailed morphological study of cave Collembola in the Dinaric karst in Western Balkans, a world’s hotspot of subterranean biodiversity. Large number and range of troglomorphic characters present in the genus Verhoeffiella with wide local radiation, make the genus a promising model for studying morphological diversification and testing evolutionary hypotheses in subterranean habitats.

Australia is home to many endemic snails, a large proportion of them still undescribed or known only by their shells. In Nitor, we use comparative anatomy and mitochondrial gene sequencing to show that shell characters in this group are convergent and often misleading, as well as revising the genus and expanding it to include ten species, four of them new. There is a close relationship between Nitor, found in coastal NSW and Queensland, and species from Lord Howe Island.

Bizarre harvestmen from the lower Amazon basin and bearing bovine-like horns or disproportionate thick processes on the back are studied in detail. Their relationships among similar species are investigated. They are found to belong to a group with increasing specializations not found anywhere in the arachnid order Opiliones.

Many tardigrades can be easily found in garden mosses, but the members of the family Echiniscidae are quite rare, thus poorly known. This paper presents morphological clues for an artificial character of the largest echiniscid genus Echiniscus, by erecting new genus restricted to Asia. Therefore, by demonstrating the value of cuticular pattern in the systematics, further changes can be made to elucidate echiniscid classification.