Meniscoessus is a genus of extinct multituberculates from the Upper Cretaceous Period that lived in North America. It is a member of the order Multituberculata, belonging to the suborder Cimolodonta and family Cimolomyidae. The multituberculates were primitive, rodent-like mammals occupying the modern rodent ecological niche. They were significant for having diverged early in mammalian evolution, co-existing with dinosaurs for ~100 million years, surviving through the Cretaceous–Paleogene extinction event and lasting until the end of the Paleogene, likely having been replaced by true rodents. Meniscoessus lived during the Santonian, Campanian and Maastrichtian ages of the Upper Cretaceous. This was a period of significant diversification of multiturbiculates, and evidence that contradicts the popular misconception that mammals were unable to thrive due to being outcompeted by the dinosaurs. They are useful as index fossils for the Judithian, Edmontonian, and Lancian faunal stages. Like most early mammals, Meniscoessus fossils mainly consist of teeth. Zofia Kielan-Jaworowska and Jørn Hurum considered them to be the "best known" members of the Cimolomyidae.

Taxonomy

History

The genus Meniscoessus was named by Edward Drinker Cope in 1882. Members of this genus have been previously classified under the following genus names: Cimolomys (partly); Dipriodon ; Halodon; Oracodon; Moeniscoessus; Selenacodon (partly); and Tripriodon. As Osborn pointed out in 1891, a number of erroneous discoveries had been made as a result of analyzing different teeth of the same animal, different individuals of the same species, and violating the principle of priority due to workers ignoring previously published discoveries. There may have been confusion with some teeth described as belonging to small carnivorous dinosaurs. These were further christened Dipriodon, Tripriodon, and others, including Triprotodon. Close similarities were then noticed with an already established dinosaur genus, Paronychodon (Cope 1876), also based on teeth from the Laramie Formation. Over time, an impressive school of names was synonymized under P. However, this is now considered a nomen dubium.

Species

(P4)]]. It was estimated to have a body mass of 1.5 kg Several other names have been in circulation, such as Meniscoessus bustus, and Meniscoessus coelatus. The first is probably a variant of M. robustus, while the latter seems to have been connected with dinosaur teeth.