Symbiotic associations of crustaceans and a pycnogonid with gelatinous zooplankton in the Gulf of California

Symbiotic associations between pelagic arthropods and gelatinous zooplankters were surveyed and analyzed via blue-water SCUBA and a remotely operated submersible (ROV) during March 2015 in the Gulf of California. Our analyses focused on hyperiid amphipods (10 species), copepods (1), and pycnogonids (1) associated with different groups of gelata. Here. we report observations on 13 previously undocumented and 4 known symbiotic associations. The nature and dynamics of these associations are still poorly understood, particularly those involving deep-living taxa. The discovery of the pycnogonid Bathypallenopsis calcanea (Stephensen, 1933) in association with the medusa Aeginura grimaldii Maas, 1904 was predicted by Hedgpeth (Deep-Sea Res 9:487-491, 1962). We include in vivo or in situ photographs of some of these associations. The Megalanceoloides, previously reported as M. remipes (Barnard), are here recognized as belonging to a new species. These new data represent a significant addition to our knowledge of these symbiotic associations in the mid- and deep waters of the Gulf of California.