On the phylogeny of Ischyroceridae (Amphipoda, Senticaudata, Corophiida), with the description of a new genus and eight new species from deep-sea Brazilian waters

摘要

The family Ischyroceridae is analysed herein by cladistic methods based on morphological characters, using both PAUP4.0b and TNT. The data matrix of 41 charactersx32 terminal taxa was constructed using DELTA. Based on the results, we comment on the phylogenetic relationships of certain genera and their synapomorphic characters, also discussing the phylogenetic position of Myersiusgen.nov., which appeared as the sister group of Bathyphotis. In addition, Pseudischyrocerus crenatipes is removed to Bathyphotis, for which a new diagnosis is provided. A taxonomic study with the Ischyroceridae collected on the continental slope (depth, 700-2000m) in the Campos Basin (20.5-24 degrees S, 40-41 degrees W) was also performed. Samples were collected in November-December2002 and July-August2003 using a box core device. As a result, a new genus and eight new species are described: Bonnierella campensissp.nov., Bonnierella laurensisp.nov., Myersius denticaudatusgen.etsp.nov., Notopoma lowryisp.nov., Notopoma teresaesp.nov., Pseudericthonius bousfieldisp.nov., Pseudericthonius concavussp.nov., and Pseudischyrocerus caecussp.nov. The genus Bonnierella is recorded for the first time from Brazilian waters, and the subspecies Bonnierella linearis linearis and Bonnierella linearis californica are elevated to species rank. Keys to the genera of Ischyroceridae used in the cladistic analysis and the world species of Notopoma are given