| abstract | A total of 33 species of Acari in 12 genera, collected from subtidal habitats on Cruise 17 of R/V ANTON BRUUN, are treated. The greatest depth from which Halacaridae were recovered was 4,100 m (Thalassarachna bandyi, T. humboldti and Copidognathus bruuni). These species show marked structural adaptations related to conditions at that depth. This suggests that Halacaridae may be found even deeper than presently known.
The new genus Bradyagaue is established for Agaue drygalskii and its congeners. The new species are: Halacarus spathulifer, Agaue magellanica, Bradyagaue quadriseta, Copidognathus subgibbus, C. fernandezi, C. crusoei, C. felicis, C. cumberlandi, C. sinuosus, C. bituberosus, C. uniareolatus, C. posticus, C. comeatus, C. anops, C. triton, Arhodeoporus mammillifer, Agauopsis productus, A. costatus, A. delicatulus, Werthella plumifera, W. vietsi vietsi, W. vietsi ambrosiensis, Parhalixodes chilensis, Scaptognathus pacificus, and Simognathus obtusus. Thalassarachna bandyi Newell 1967, T. humboldti Newell 1967 and Copidognathus bruuni Newell 1967 are treated briefly. Two species of Halacarus and two of Lohr.nannella are described briefly but not named since they are represented only by nymphs. C. cumberlandi and W. vietsi vietsi are intertidal forms but are described to permit comparison with the subtidal species, C. sinuosus, C. fernandezi, and W. vietsi ambrosiensis.
The subtidal species were collected at depths between 62 and 4,100 m in the SE Pacific. Seven of the species came from depths greater than 1,500 m. The fauna is analyzed according to horizontal as well as vertical distribution. There was a noticeable zonation according to depth and also indications of endemism centering about Juan Fernandez and San Felix Islands. Also included are speculations on the magnitude of the subtidal fauna of the SE Pacific and the significance of this for the world fauna of Halacaridae. |