The diversity of Western Australian Onychophora has yet to be fully uncovered and is burdened by the conserved morphology and cryptic habits of the phylum. Here we describe three new species in the genus Kumbadjena with the first molecular investigation of the Onychophora in Western Australia. The ranges of these new species suggest that they are short range endemics. The prevalence of endemics in this region has implications for the conservation of biodiversity.

We characterize for the first time the intraspecific genetic diversity in the South American crayfish genus Parastacus. Phylogenetic reconstructions indicate the existence of six lineages, of which only one can be considered as P. brasiliensis. Our study shows that P. brasiliensis occurs mainly in Guaíba Lake Basin and the studied populations show limited connectivity and gene flow, probably due to habitat fragmentation. We emphasize the importance of preserving these distinct gene pools in order to maintain species genetic diversity.

Cosmopolitanism in the polychaete group is increasingly shown to be an artefact of several historical factors. The application of taxonomic and molecular revisions found that a local nereidid, Pseudonereis podocirra was incorrectly synonymised with the apparently cosmopolitan, P. variegata. This demonstrates the need for a revision of P. variegata from its type locality and all junior synonyms outside of its native range.

This work highlights the importance of adequate taxonomy in linking morphological and molecular characters within integrative taxonomy. Species boundaries are investigated on the basis of colouration, chaetotaxy and molecular data in a Dicranocentrus species complex from China. Integrative approaches can provide better species-level resolution to “cryptic” diversity.

Tropical forests of Asia are relatively unexplored for terrestrial arthropods. In this study, we use DNA, morphology and distribution data for a group of scolopendrid centipedes to revise its systematics, and describe three new species from a global biodiversity hotspot, the Western Ghats, India. We also rediscovered a species after 130 years from the lesser-known Eastern Ghats.

The diversity of many groups of marine invertebrates remain poorly understood and here we revise the systematics of the Indo-West pacific sea slug genus Phanerophthalmus based on molecular phylogenetics and morphological characters. We recognized 17 species, 10 of them new to science. The Coral Triangle is the area with highest diversity and contrary to prevalent view only two species have distributions spanning the Indian and Pacific oceans.

The first nudibranch phylogeny of the genus Halgerda comprising specimens from the western Indian Ocean is presented. Six new species are described, including one pseudocryptic species that has been misidentified since 1905. Our results suggest that there are two centres of divergence for the genus, which have been masked by the lack of data from the western Indian Ocean.

Caridina longirostris is a species of freshwater shrimp formerly thought to be widespread in the Indo-Pacific area, but as new specimens were collected, the validity of this species was questionned for most of the localities. Combined morphological and molecular analyses showed that C. longirostris is absent from the Indo-Pacific area and that there are four different species previously confused with it in the region. This study helped resolving part of the taxonomic confusion surrounding the C. nilotica complex.

A new perspective on morphological variation within genus Heterocypris is given. By exploring a large number of metric characters and the labrum and maxillular palp shape, the most discriminating characters and new insight into their variability are revealed. Comparative analyses of standard and newly introduced traits present a step towards a valid, precise and reliable revision of genus Heterocypris.

Since M. rapax has the largest range for fiddler crabs along the western Atlantic coast, it was examined for significant intraspecific variation. Variation within the species was estimated from morphological, physiological, behavioral and genetic perspectives. Although extensive variation is evident among populations across the distribution, the evolutionary significant units are not sufficient differentiated to warrant full recognition at the species level.