''Hahnodon'' ("Hahn's tooth") is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

mammaliaform Mammaliaformes ("mammalian forms") is a clade that contains the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts. It is defined as the clade originating from the most recent com ...

s from the Early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Ksar Metlili Formation The Ksar Metlili Formation is a geological formation in eastern High Atlas of Morocco, it is late Tithonian to Berriasian In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision ...

in Morocco. Although originally considered to be a relatively early member of the extinct clade

Multituberculata Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, a ...

, recent studies indicate that it instead is a haramiyid.

Fossils and distribution

''Hahnodon taqueti'' is based on a single lower molar found in Lower Cretaceous

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

Classification

Denise Sigogneau-Russell Denise Sigogneau-Russell (born ''c.'' 1941/42) is a French palaeontologist who specialises in mammals from the Mesozoic, particularly from France and the UK. She is currently based at the Muséum National d'Histoire Naturelle. Background Denise S ...

(1991) classified ''Hahnodon'' as a member of Multituberculata, but others later considered it to be related to members of Haramiyida. The description of ''

Cifelliodon ''Cifelliodon'' is an extinct genus of mammaliaforms from the Lower Cretaceous of North America. In the describing paper, it was considered one of the latest surviving haramiyids yet known, belonging to the family Hahnodontidae. Its discovery led ...

'' from North America confirmed that ''Hahnodon'' — and by extension, Hahnodontidae — belong to Haramiyida.Adam K. Huttenlocker; David M. Grossnickle; James I. Kirkland; Julia A. Schultz; Zhe-Xi Luo (2018). "Late-surviving stem mammal links the lowermost Cretaceous of North America and Gondwana". Nature. in press. doi:10.1038/s41586-018-0126-y.

References

Bibliography

* Sigogneau-Russell (1991), "First evidence of

(Mammalia) in the Mesozoic of Africa". Neues Jahrb Geol Paläontol, Monatshefte, p. 119-125. * Kielan-Jaworowska Z & Hurum JH (2001), "Phylogeny and Systematics of multituberculate mammals". ''Paleontology'' 44, p. 389-429. * Much of this information has been derived fro

MESOZOIC MAMMALS: Basal Multituberculata, an Internet directory. Haramiyida Prehistoric cynodont genera Berriasian life Early Cretaceous synapsids Cretaceous Morocco Fossils of Morocco Fossil taxa described in 1991 Taxa named by Denise Sigogneau‐Russell {{cretaceous-animal-stub