New insights into the systematics of Lumbricillus and Marionina (Clitellata: Enchytraeidae) inferred from Southern Hemisphere samples, including three new species

Abstract

Abstract Enchytraeid worms collected in South Africa and on the Marion, South Orkney, South Georgia and South Shetland Islands during 2008–2015 were studied using morphology and seven genetic markers. Nine species were recognized: one terrestrial (Christensenidrilus blocki) and all the others marine littoral (five Lumbricillus and three Marionina s.s.). An estimated phylogeny including other enchytraeids from the Northern Hemisphere, many of which are members of Lumbricillus and some representing Marionina s.l., confirmed a non-monophyletic Lumbricillus, with some of its current species closely related to Grania or Marionina s.s. The phylogeny also corroborated a non-monophyletic Marionina s.l., with Marionina s.s. closely related to Grania and Lumbricillus s.l., but not to the remaining sequenced ‘Marionina’ or to Ch. blocki. These results provide a long-needed starting point for a revision of both Marionina and Lumbricillus. We provide morphological descriptions of all nine species, three of which are new to science: Lumbricillus finisafricae sp. nov., Lumbricillus nivalis sp. nov., and Marionina fusca sp. nov. Comments on three related species of Marionina s.s. based on re-examined type material are also provided.