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.
Kielan-Jaworowska, Zofia; Hurum, J.H. (2001). "Phylogeny and Systematics of Multituberculate Mammals". Palaeontology. 44 (3): 389–429. doi:10.1111/1475-4983.00185.
Kielan-Jaworowska, Zofia; Qi, Tao (1990). "Fossorial adaptations of a Taeniolabidoid Multituberculate mammal from the Eocene of China". Vertebrata PalAsiatica. 28 (2): 83–94.
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. doi:10.1038/nature10880. PMID22419156. S2CID4419772.
Further reading
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.