Class Mammalia Linnaeus, 1758 - mammals Subclass Boreosphenida Luo, Cifelli & Kielan-Jaworowska, 2001 - tribotherians see Clade Boreosphenida Luo, Cifelli & Kielan-Jaworowska 2001 Genus †Zygiocuspis Cifelli, 1990, incertae sedis [monotypic] 1 †Zygiocuspis goldingi Cifelli, 1990