| Lambdopsalidae | |
|---|---|
| |
| Lambdopsalis bulla - skull | |
Scientific classification 
| |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | †Multituberculata |
| Superfamily: | †Taeniolabidoidea |
| Family: | †Lambdopsalidae Chow and Qi, 1978[1] |
| Genera | |
Lambdopsalidae is a family of extinct multituberculate mammals from the Late Paleocene of Asia. They are part of Taeniolabidoidea, a clade otherwise present in the Early Paleocene (and possibly the Late Cretaceous) of North America. The Lambdopsalids probably evolved from a single radiation that spread into Asia from North America in the mid-Paleocene or earlier. They are represented by the genera Lambdopsalis, Sphenopsalis and Prionessus.[2][1] This group was first defined in 1978 by Chow and Tao Qi.[3]
The Lambdopsalids were small mammals, with estimated adult body masses of about 0.4 kilograms (0.88 lb) to 0.8 kilograms (1.8 lb).[4] They are notable for their enlarged teeth that implies adaptations towards leaf grazing,[2] and adaptations for burrowing such as a short and flat snout, robust humeri, stiff neck and enlarged lower incisors.[5][6] This group has a shared dental formula of 2.0.1.21.0.1.2[3] Examples of Lambdopsalis are notable for offering direct evidence of hair and enamel and tooth prism patterns among multituberculates.[7]
Lambdopsalids lived during the Thanetian, the last stage of the Paleocene, with fossils ranging from 59-55 million years ago.[8] They disappeared around the PETM.
