Loxaulax

Loxaulax is an extinct mammal from the Lower Cretaceous of southern England. Material has also been reported from the Jurassic of North America, but I haven't yet been able to find any confirmation of this. It was a member of the also extinct order of Multituberculata, and lived alongside dinosaurs.
(For the technically minded, suborder "Plagiaulacida", family Eobaataridae.)

Genus: Loxaulax Simpson GG, 1928
Reference: Simpson (1928), A catalogue of the Mesozoic mammalia in the geological department of the British Museum. London: British Museum (Nat Hist).

Species: Loxaulax valdensis Simpson GG, 1928
Place: Cliff End bonebed, Hastings?
Country: England
Age: Valangian, Lower Cretaceous
Remarks: Based on a tooth. More recently, "Butler and Ford reported some IoW (Isle of Wight) Wealden[?] mammal teeth several decades ago. They identified one of the teeth as belonging to the multituberculate Loxaulax but weren't sure about the others. Other IoW Wealden mammal teeth have been found since but have yet to be written up," (with thanks to Darren Naish).
The friendly souls of the Isle of Wight Museum inform me that sieving is underway at one fossil location. This suggests new mammal finds are not unlikely.
The American material is mentioned in John H Burkitt's monumental webpage; [1] (http://216.239.39.100/search?q=cache:dCPaKoK0NcQC:www.cougarhillweb.org/mammals.pdf+loxaulax&hl=en) Mammals, A World of Living and Extinct Species.
Reference: Simpson (1928), A catalogue of the Mesozoic mammalia in the geological department of the British Museum. London: British Museum (Nat Hist).

Page reference: Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.

(This information has been derived from [2] (http://home.arcor.de/ktdykes/basmult.htm) MESOZOIC MAMMALS; Plagiaulacidae, Albionbaataridae, Eobaataridae & Arginbaataridae, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)