''Marada arcanum'' is a species of

Vombatiformes The Vombatiformes are one of the three suborders of the large marsupial order Diprotodontia. Seven of the nine known families within this suborder are extinct; only the families Phascolarctidae, with the koala, and Vombatidae, with three ext ...

discovered in 2001 at the Oligocene Hiatus Site at Riversleigh. It is the only member of the genus ''Marada''. It exhibits

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, an ...

and

apomorphic In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

features making the determination of its taxonomic placement difficult. It has been placed within its own family, Maradidae. The specimen consists of the right dentary, with the first

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

but missing the

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...

, the whole of the horizontal ramus with intact

premolar The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...

three and molars one to four. The posterior is missing the coronoid process, the articular condyle and the angular process. The new species, genus, and family were described in 2007 by the Australian palaeontologist

Karen Black Karen Blanche Black (née Ziegler; July 1, 1939 – August 8, 2013) was an American actress, screenwriter, singer, and songwriter. She rose to prominence for her work in various studio and independent films in the 1970s, frequently portr ...

References

{{Taxonbar, from1=Q6540375, from2=Q18608866, from3=Q12071624 Prehistoric vombatiforms Riversleigh fauna Fossil taxa described in 2007