DELTAMYSIS-HOLMQUISTAE, A NEW GENUS AND SPECIES OF MYSIDACEA FROM THE SACRAMENTO-SAN-JOAQUIN ESTUARY OF CALIFORNIA (MYSIDAE, MYSINAE, HETEROMYSINI)

Deltamysis holmquistae is described from the Sacramento-San Joaquin estuary of central California. Its sparsity in plankton net samples suggests that its supposed habitat has not been sampled adequately. Limited sampling in tule beds failed to take specimens. Deltamysis holmquistae may be an introduced species; it was not found until 1977 despite sampling for Mysidacea in the estuary since 1963. Characteristics of the tribe Heteromysini are redefined to include Deltamysis. The new definition allows the addition of Burrimysis and the transfer of Mysidetes from the Leptomysini to the Heteromysini. A new key to the Heteromysini is given which includes the subgenera of Heteromysis.