Geographical and bathymetric distribution of mysids (Crustacea: Mysida) in the seas of the Iberian Peninsula.

The zoogeographic distribution of mysid species occurring in the diverse seas of the Iberian Peninsula and neighbouring areas is analysed. For each species, bathymetric range and localities data are reported. A total of 129 mysid species belonging to 50 genera have been recorded, representing 11% of all known world extant species and the 28% of genera. Littoral mysids are the most diverse group (64 species) followed by the outer-self to upper-bathyal slope with 54 known species. Patterns of bathymetric zonation are characterized by four bathymetric discontinuities at about 100, 500, 1300 and 2700 m. Each geographical region is characterized by the presence of a mixture of exclusive and shared species composition. Mysid distributions suggest that an important grouping of species present in the Iberian fauna share a common origin. Based on the analysis of published records and reported species, it is suggested that there is a high probability of the discovery of new species of Mysida in the water surrounding the Iberian Peninsula.

An annotated check-list of lophogastrids (Crustacea: Lophogastrida) from the seas of the Iberian Peninsula.

The zoogeographic distribution of lophogastrid species occurring in the diverse seas of the Iberian Peninsula and neighbouring areas is analysed. For each species, data on general distribution, bathymetric ranges, habitat and localities reported on published data are provided. A total of 16 lophogastrids species belonging to 6 genera have been recorded, representing the 30% of all known world extant species and the 67% of genera. Two of them are common to the Atlantic and the Mediterranean. All known Iberian species are present in the Macaronesian region, 43.8% in the North-western Atlantic and 12.5% in the western Mediterranean. Lophogastrid distributions suggest the existence of an evolution and distribution centre of the group located around the Macaronesian Islands.

Petalophthalmus papilloculatus sp. nov. (Crustacea: Mysida: Petalophthalmidae), a new bathyal suprabenthic mysid from the Galicia Bank (NE Atlantic Ocean).

A new species of the genus Petalophthalmus (Crustacea: Mysida: Petalophthalmidae) is described, based on specimens collected from the Galicia Bank (northeastern Atlantic Ocean). This species can be distinguished from the other species of the genus Petalophthalmus by the presence of an ocular papilla on its eyes. P. papilloculatus sp. nov. is morphologically close to the cosmopolitan species P. armiger Willemoes-Suhm, 1875, but can be easily distinguished by the presence of an ocular papilla, the longer antennal scales bearing an apical lobe, the unique chitinous ridge on the molar process, the outwards lengthening of the three cuspidate setae on the outer margin of the uropodal exopod and the armature of the telson. This new species lives on fine and very fine sandy bottoms at the bank flanks, between 1536 and 1809 m depths. Probably related to the special biogeographic characteristics of seamounts, the morphological affinity between the new species and P. armiger supports the hypothesis on a common ancestry and recent divergence between both deep sea mysids. An identification key to world species of Petalophthalmus is provided.

The ascidian-associated mysid Corellamysis eltanina gen.nov., sp.nov. (Mysida, Mysidae, Heteromysinae): a new symbiotic relationship from the Southern Ocean.

A new mysid species representing a new genus is described based on specimens collected in the 1968 cruise of the U.S. Navy Ship Eltanin from the Macquarie Island region (Southern Ocean). The new mysid, Corellamysis eltanina, is characterized by the globular eyes lacking definite eyestalks, the seven and eighth thoracic endopods specialized as gnathopods forming a strong subchela, and by the armature and shape of the uropod endopod and telson. Corellamysis eltanina lives only in the branchial sacs of the ascidian Corella brewinae suggesting an obligate endocommensal symbiotic association. Therefore, this is the first known report of a mysid living symbiotically with a benthic tunicate, as well as the first report of a mysid symbiosis from the Southern Ocean. The distribution and habitats of known symbiont mysids are reviewed. An update of identification key to world genera and subgenera of Heteromysinae is suggested.