Lambdopsalidae is a family of extinct multituberculate mammals from the Late

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

. They are part of

Taeniolabidoidea Taeniolabidoidea is a group of extinct mammals known from North America and Asia. They were the largest members of the extinct order Multituberculata, as well as the largest non- therian mammals. ''Lambdopsalis'' even provides direct fossil ev ...

, a clade otherwise present in the Early Paleocene (and possibly the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

) of North America; lambdopsalids, therefore, probably evolved from a single radiation that spread into Asia from North America in the mid-Paleocene or earlier. They are represented by the genus ''

Lambdopsalis ''Lambdopsalis bulla'' is an extinct multituberculate mammal from the Late Paleocene of China and Mongolia. It is placed within the suborder Cimolodonta and is a member of the superfamily Taeniolabidoidea. Fossil remains have been found in the L ...

'', ''

Sphenopsalis ''Sphenopsalis'' is a genus of extinct mammal from the Paleocene of Central Asia. It was a member of the extinct order Multituberculata, and lies within the suborder Cimolodonta and the superfamily Taeniolabidoidea. The genus was named by Willia ...

'' and ''

Prionessus ''Prionessus'' is a genus of extinct mammal from the Paleocene of Central Asia. It was a member of the extinct order Multituberculata within the suborder Cimolodonta and superfamily Taeniolabidoidea. The genus was named by Matthew W.D. and Gran ...

''. Though they haven't become as large as ''

Taeniolabis ''Taeniolabis'' ("banded incisor") is a genus of extinct multituberculate mammal from the Paleocene of North America. Description It is the largest known member of the extinct order Multituberculata, as well as the largest non-therian ma ...

'', lambdopsalids were still large by multituberculate standards, the largest species weighting around 30 kg. They are notable for their unique dental speciations such as

hypsodonty Hypsodont is a pattern of dentition with high-crowned teeth and enamel extending past the gum line, providing extra material for wear and tear. Some examples of animals with hypsodont dentition are cows and horses; all animals that feed on grit ...

, which seem to imply speciations towards

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

. ''Lambdopsalis'' is notable for offering direct evidence of hair and enamel and tooth prism patterns among multituberculates. Lambdopsalids lived in the final stages of the Paleocene, disappearing around the PETM. They co-existed with a variety of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...

species - in fact, rodents are thought to have first evolved and diversified in Asia -, indicating that there wasn't competition between both groups, having-coexisted together for several million years.Wood, D. Joseph (2010). The Extinction of the Multituberculates Outside North America: a Global Approach to Testing the Competition Model (M.S.). The Ohio State University.

References

{{Taxonbar, from=Q22936975 Cimolodonts Eocene extinctions Paleocene mammals Prehistoric mammal families