Four species of Sphaerodoridae (Polychaeta) including one new genus and three new species are described from Alaska.
Amacrodorum bipapillatum is a new genus and species from the Aleutian Island of Akutan;
Sphaerodoropsis uzintunensis and
S. katchemakensis are both new species from Katchemak Bay, Homer;
Sphaerodoropsis sphaerulifer (Moore, 1909) is also reported.
Amacrodorum is partly characterized by the absence of macro papillae and the presence of two kinds of papillae. It is strongly isolated in the family, and superficially similar to
Levidorum Hartman in that both taxa lack macropapillae. However,
Amacrodorum differs from
Levidorum in not having smooth body surfaces and in having head appendages;
Levidorum was recently assigned to a separate family that may be more closely related to syllids (Perkins 1987). A key to described species of
Sphaerodoropsis recorded from Alaska is presented.