Based on molecular and morphological data, we describe three new genera and four new species of monothalamids from the sublittoral zone (21–250 m) in South Georgia fjords that belong to different monothalamid clades. Limaxia alba gen. nov. sp. nov. (Clade A) has an elongate, subcylindrical test, 359–688 µm long, with some detritus attached to the organic wall. Hilla argentea gen. nov. sp. nov. (Clade Y) has a cylindrical, finely agglutinated test, 535–755 µm long. Pseudoconqueria lenticularis gen. nov. sp. nov. branches separately. It has a spindle-shaped, finely agglutinated test, 280–574 µm long. Bathyallogromia olivacea sp. nov. (Clade C) has an ovate organic-walled test, 369–433 µm long. We present the first genetic data on two monothalamid species originally described from South Georgia, Hippocrepinella alba (Clade C) and Hippocrepinella hirudinea (Clade D), as well as a single sequence for C. delacai (Clade J) originally described from McMurdo Sound, Antarctica. In addition, we report nine undescribed species branching in six different monothalamid clades (A, B, BM, C, J, Y), eight of them sampled around South Georgia and one collected from the Falkland Islands near Stanley.
