An 'Acmarhachis typicalis' Zone Trilobite Fauna from the Cambrian of Northern Victoria Land, Antarctica

Trilobites from about 200m of section of the Spurs Formation, 4km SW of Helix Pass, northern Victoria Land, Antarctica, include the Mindyallan zone fossil Acmarhachis typicalis. There are four agnostoid taxa including the new species Ammagnostus antarcticus and over 20 taxa of polymerid trilobites including the new species Doremataspis contracta. A new genus and species, Jamrogia jamrogensis, is placed in a new family, the Jamrogiidae. A new genus, Catillicephalina, type species C. glasgowensis, is erected. The trilobites occur within a succession of calcareous siltstones with thin intervals of dark silty limestones; an offshore outer shelf to upper slope depositional environment is suggested. There are strong taxonomic affinities with the Mindyallan faunas of Queensland and China, with some affinities to Greenland and North America.