Tubificidae (oligochaeta) from the Ross Sea (Antarctica), with descriptions of one new genus and two new species

Three species,Torodrilus gelidus sp. nov. (subfamily Rhyacodrilinae),Rossidrilus terraenovae gen. et sp. nov. (Limnodriloidinae), and a second unnamed species of Limnodriloidinae, are reported from marine sediments in Terra Nova Bay, Ross Sea. Torodrilus gelidus is distinguished fromT. lowryi Cook, 1970 by its setal pattern (with few exceptions, both anterior and posterior setae are single-pointed in sexually mature specimens ofT. gelidus) and the morphology of its male protuberances (the latter folded over a midventral bursa in segment XI).Rossidrilus terraenovae is characterized by large diverticula attached to the oesophagus in the posterior part of segment IX, unpaired male and spermathecal pores, heavily muscular and entally ciliated atrial ampullae, elongate prostatic pads, and a deep, unpaired and muscular, copulatory sac. It is the first species of its subfamily to be described from Antarctic waters.