Major Revisions in Pancrustacean Phylogeny and Evidence of Sensitivity to Taxon Sampling.

The clade Pancrustacea, comprising crustaceans and hexapods, is the most diverse group of animals on earth, containing over 80% of animal species and half of animal biomass. It has been the subject of several recent phylogenomic analyses, yet relationships within Pancrustacea show a notable lack of stability. Here, the phylogeny is estimated with expanded taxon sampling, particularly of malacostracans.

Adding pieces to the puzzle: insights into diversity and distribution patterns of Cumacea (Crustacea: Peracarida) from the deep North Atlantic to the Arctic Ocean.

The Nordic Seas have one of the highest water-mass diversities in the world, yet large knowledge gaps exist in biodiversity structure and biogeographical distribution patterns of the deep macrobenthic fauna. This study focuses on the marine bottom-dwelling peracarid crustacean taxon Cumacea from northern waters, using a combined approach of morphological and molecular techniques to present one of the first insights into genetic variability of this taxon. In total, 947 specimens were assigned to 77 morphologically differing species, representing all seven known families from the North Atlantic.

"Unicorn from Hades", a new genus of Mysidae (Malacostraca: Mysida) from the Mariana Trench, with a systematic analysis of the deep-sea mysids.

Since the 19th century, oceanic explorations have confirmed that the hadal zone (water depth > 6000 m) is not lifeless, but contains many fascinating organisms. Amongst them are the Mysida, which is a group of crustaceans found in many deep-sea trenches. Based on morphological observations and molecular phylogenetic analyses of an undescribed taxon within the subfamily Erythropinae, a new genus of deep-sea mysids, Xenomysis gen.

Phylogenetic evidence that both ancient vicariance and dispersal have contributed to the biogeographic patterns of anchialine cave shrimps.

Cave shrimps from the genera Typhlatya, Stygiocaris and Typhlopatsa (Atyidae) are restricted to specialised coastal subterranean habitats or nearby freshwaters and have a highly disconnected distribution (Eastern Pacific, Caribbean, Atlantic, Mediterranean, Madagascar, Australia). The combination of a wide distribution and a limited dispersal potential suggests a large-scale process has generated this geographic pattern. Tectonic plates that fragment ancestral ranges (vicariance) has often been assumed to cause this process, with the biota as passive passengers on continental blocks.

Taxonomic review of the orders Mysida and Stygiomysida (crustacea, peracarida).

The order Mysida (2 families, 178 genera, 1132 species) contains species across a broad range of habitats, such as subterranean, fresh, brackish, coastal, and surface to deep-sea habitats. The Stygiomysida (2 families, 2 genera, 16 species), however, are found primarily in subterranean waters, but always in waters with a marine influence. The Mysida and Stygiomysida body is divided into three main regions: cephalon, thorax, and abdomen.

A taxonomical review of the Gnathophausia (Crustacea, Lophogastrida), with new records from the northern mid-Atlantic ridge.

Taxonomy of 11 species contained within the Lophogastrida genus Gnathophausia is presented. We report new records of G. affinis, G.

The magnitude of global marine species diversity.

Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered.

Results: There are ∼226,000 eukaryotic marine species described.

The disunity of "Mysidacea" (Crustacea).

New studies on malacostracan relationships have drawn attention to issues concerning monophyly of the order Mysidacea, manifested in recent crustacean classifications that treat the taxon as two separate orders, Lophogastrida and Mysida. We present molecular phylogenies of these orders based on complete sequences of nuclear small-subunit ribosomal DNA (18S rRNA), and morphological evidence is used to revise the classification of the order Mysida to better reflect evolutionary history. A secondary structure model for 18S rRNA was constructed and used to assign putative stem and loop regions to two groups of partitions for phylogenetic analyses.