The South Australian members of the flat-millipede genera Oncocladosoma Jeekel, 1985 and Somethus
Chamberlin, 1920 are revised using an integrative approach incorporating sequence data and morphology. The partial
mitochondrialcytochromecoxidasesubunitI(COI)barcodinggeneandpartialnuclearribosomal28SrRNAwereamplified
and sequenced for 15 Oncocladosoma specimens and 10 Somethus specimens and the datasets were used for molecular
phylogenetic analysis and genetic distance determination. Both morphology and molecular data indicate that all species of
Oncocladosoma fall within Somethus, and therefore, Oncocladosoma is synonymised with Somethus. Within those species
supported by molecular data, features of the solenomere tip are relatively stable and useful for species identification. 28S
rRNAhasproventoprovidesufficientnucleotidevariationtoprovisionallydiscriminatespecies.Oncocladosomacastaneum
ingensJeekel,1985,O.clavigerumJeekel,1985andO.conigerumJeekel,1985arejuniorsynonymsofSomethuscastaneus,
comb. nov., and Somethus modicus Jeekel, 2002 is a synonym of S. scopiferus Jeekel, 2002. New records and electron
scanning micrographs of gonopods are provided for S. castaneus, comb. nov., S. inflatus (Jeekel, 2002), comb. nov.,
S. lancearius Jeekel, 2002, S. scopiferus Jeekel, 2002, and Somethus grossi Jeekel, 1985, together with a key to the South
Australian species of Somethus.
