Lambdopsalis

Lambdopsalis is a Chinese mammal genus from the Paleocene of North America. This animal was a relatively large member of the extinct order of Multituberculata.
For those of a technical inclination, this animal is within the Suborder of Cimolodonta, and a member of the superfamily Taeniolabidoidea.

Genus: Lambdopsalis Chow M & Qi T, 1978

Species: Lambdopsalis bulla Chow & Qi, 1978
Place: Nao-mugen & Bayn Ulan
Country: China
Age: Upper Paleocene
Remarks: This genus of burrowing multituberculate mammal, used to provide the earliest direct evidence of mammal fur. (This is out of date since May 2002. The new record holder, Eomaia, comes from the Lower Cretaceous of China.) Hair is highly unlikely to fossilize. There are indications that it first appeared on non-mammalian therapsids (Therapsida), way back in the Triassic, or even earlier. This is inferred from small hollows on the bone of the snout, which may and probably did provide space for concentrations of nerves and blood vessels. It’s a feature also known from cats. (If you have one at home, please don’t cut it open to check). This adaptation allows Felix to use its whiskers, (specialized hairs), as effective sensory organs.
However, exceptional fossils from China do actually include mammal fur, some of which is from Lambdopsalis. These are coprolites, fossilized crap, which contain the undigested leftovers excreted by carnivores.
Reference: Chow & Qi (1978), Paleocene mammalian fossils from Nomogen Formation of Inner Mongolia. Vertebrata PalAsiatica 16(2), p.77-85. ´ Page reference: Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.

(This information is derived from [1] (http://home.arcor.de/ktdykes/taenio.htm) MESOZOIC MAMMALS; Eucosmodontidae, Microcosmodontidae and Taeniolabidoidea, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)