Taeniolabis is a member of the Taeniolabidoidea, a superfamily of multituberculates that are known for their highly derived teeth, and a short wide snout with a blocky head.[3] The teeth modifications were likely an adaptation for herbivory that may have resulted from rapid diversification of angiosperms at the very end of the Cretaceous, which would thus have created opportunities for novel specialization in herbivores.[4] It is the largest known multituberculate, as well as the largest allotherian mammal,[5][6] with T. taoensis weighing up to 34 kilograms (75 lb).[7] Species under this genus have been known under other names.[8]Taeniolabis taoensis is found frequently enough and in a very limited time range that it can be used as an index fossil for the Puercan faunal stage within Danian aged fossil deposits.[9][10]
Taeniolabis lamberti was named by Nancy Simmons in 1987.[12] It has been found in the Danian aged Tullock Formation of Montana. It is not quite as large as T. taoensis, but still a hefty size for a multituberculate, weighing around 11 kilograms (24 lb).[13]
Taeniolabis taoensis was originally named Taeniolabis sulcatus by Cope in 1882 as the type species of the genus.[14] It was later renamed as T. taoensis. Known fossils date to approximately 64 million years of age.[15] They are found in Danian aged deposits of the Nacimiento Formation of New Mexico, the Ravenscrag Formation of Saskatchewan and the Denver Formation of Colorado.[16] This species likely had a roughly16 centimetres (6.3 in) long skull and had an average body mass of 22.7 kilograms (50 lb), which is approximately the size of a modern beaver. The species was once considered to have had a body mass of up to 100 kg and sized like a sheep[17] or larger by extrapolating body size on the basis of their huge teeth. However, improved analyses and the realization that the teeth were extraordinarily robust due to herbivory rather has generally disproved that.[18][19]
Wilson, Gregory P.; Evans, Alistair R.; Corfe, Ian J.; Smits, Peter D.; Fortelius, Mikael; Jernvall, Jukka (2012). "Adaptive radiation of multituberculate mammals before the extinction of dinosaurs". Nature. 483 (7390): 457–460. Bibcode:2012Natur.483..457W. doi:10.1038/nature10880. PMID22419156. S2CID4419772.
Further reading
Cope, E.D. (1882). "Mammalia in the Laramie Formation". American Naturalist. 16 (10): 830–831.