Largest Mesozoic Mammals
Schowalteria clemensi: Known only from one skull, but seems comparable to latter taeniodonts in size, ranging somewhere between 10 to 50 kg. A specialised herbivore.
2. Bubodens magnus: Represented by a single tooth. It is enormous by multituberculate standards, and probably indicative of an animal above 16 kg (it is described as “beaver sized”). Presumably a specialised herbivore.
3. Repenomamus giganticus: Only “giant” Mesozoic mammal known from fairly good material. Measuring about a meter long and weighting at least up to 14 kg. A specialised carnivore.
4. Kollikodon ritchiei: Conflicting sources on this one. It may have been up to a meter long, certainly putting it above R. giganticus (monotremes are proportionally much more robust), but some sources also list it as “platypus size”. A molluscivore or piscivore.
5. Oxlestes grandis: Possibly slightly smaller than R. giganticus. There is some debate about how large its skull was (10 vs 7.5 centimeters), though the former seems to be the most convincing measurements for now. A carnivore.
6. Khuduklestes bohlini: “Subequal” in size to O. grandis. Possibly carnivorous.
7. Mesungulatids: Most sources are rather vague on estimated sizes (in part due to the lack of modern analogues, in part due to how rare postcranial material is), but the larger forms likeColoniatherium seem to be around 6-13 kg. Specialised herbivores.
8. Vintana sertichi: Known from only one skull. Estimated to be around 9 kilos. Specialised herbivore.
9. Altacreodus magnus: Known from various specimens. At around 9 kilos, it is the largest of the Hell Creek mammals. Specialised carnivore.
10. Didelphodon vorax: Known from several remains. The largest of the Hell Creek metatherians at 6-9 kilos. Molluscivore or carnivore.