Meniscoessus fossil map
Where fossils of Meniscoessus have been found, shown on the Earth as it looked about 66 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 66 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Early mammals |
|---|---|
| Lived | 85.7–66 million years ago (Santonian to Maastrichtian) |
| Periods | Cretaceous |
| Family | Cimolomyidae |
| Named by | Cope 1882 |
| Fossil records | 330 occurrences at 98 locations (PBDB) |
| Found in | United States, Canada |
| Rock formations | Hell Creek, Lance, Judith River, Oldman, Frenchman, Wahweap |
About Meniscoessus
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likely having been replaced by true rodents.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.
Text in “About” is quoted from the Wikipedia article Meniscoessus (revision 1354727447), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q12901024.
