New species of the deep-sea munnopsid genus Tytthocope (Crustacea, Isopoda, Asellota) from the South Atlantic and the Southern Ocean.

In the benthic samples collected during the deep-sea expeditions ANDEEP from the Weddell Sea and DIVA from the Argentine Basin the isopod family Munnopsidae was the most specious and numerous. Among the collected munnopsids three new species of Tytthocope Wilson & Hessler, 1981 have been discovered. Tytthocope is one of six genera of the subfamily Eurycopinae. It differs from other genera of the Eurycopinae by having a strongly reduced pereonite 7 and inflated pleotelson. Until now the genus consisted of five described species: four of them are known from the northern Atlantic and only one species, T. sulcifrons (Barnard, 1920) was described from the southern Atlantic off the South Africa coast. The five known species of Tytthocope have been recorded from depths less than 1461 m. Descriptions of three new species of Tytthocope collected in the South Atlantic and Southern Ocean at depths between 1530-4608 m, T. divae sp. nov., T. fahrbachi sp. nov. and T. longitelson sp. nov. are presented in the paper. T. sulcifrons is redescribed herein based on the type material.

The first record of Gnathostenetroididea Kussakin, 1967 from Australian waters with description of four new species of Gnathostenetroides Amar, 1957 (Crustacea: Isopoda: Asellota) from the Great Barrier Reef.

The asellote family Gnathostenetroididae Kussakin, 1967 is reported for the first time from Australian waters. Four new species of Gnathostenetroides Amar, 1957 from the Great Barrier Reef are described. The genus Maresiella Fresi and Scipione, 1980 is here placed into synonymy with Gnathostenetroides and a new diagnosis is given for Gnathostenetroides together with a key to the 12 species and a map of the distribution of the genus. The genus Dignatroides Stock and Vonk, 1990 is placed into synonymy with Caecostenetroides Fresi and Schiecke, 1968, and a new composition of the family Gnathostenetroididae, the updated diagnosis and a key to the three genera are provided.

Shallow-water northern hemisphere Jaera (Crustacea, Isopoda, Janiridae) found on whale bones in the southern ocean deep sea: ecology and description of Jaera tyleri sp. nov.

The skeleton of a natural whale fall discovered in the Southern Ocean at 1,445 m was densely covered by one small, janirid isopod. Jaera tyleri sp. nov. is the first of its genus found in the southern hemisphere and in the deep sea and is described herein. Morphological and molecular investigations revealed the systematic position of this species new to science. Phylogenetic analysis of the 18S locus confirms that this species falls in a strongly supported monophyletic clade of Jaera species. The whale bone habitat of J. tyleri sp. nov. is quite different from those of other species of the genus Jaera. The analysis of bathymetric and distribution patterns of the Janiridae in general and Jaera specifically confirm the unusualness of the habitat for this isopod species. The abundance of J. tyleri sp. nov. on the whale bones and its absence from other nearby habitats suggests it to be a whale-fall specialist. The analysis of the size-frequency distributions of J. tyleri sp. nov. suggests multimodal population structure with continuous breeding activity throughout the year. The fecundity of the species is low but in line with reduced fecundity observed in polar and small-sized isopods.