Plagiaulax

Plagiaulax is an extinct mammal from the Lower Cretaceous of Europe. It was a member of the also extinct order of Multituberculata, and shared the world with dinosaurs.
(For the technically minded, suborder "Plagiaulacida", family Plagiaulacidae.)

Genus: Plagiaulax Falconer H. 1857

Species: Plagiaulax becklesii
Place: Durlston Bay, Dorset
Country: England
Age: Lower Cretaceous
Remarks: Known from at least one partial lower jaw with teeth, though there may well be further specimens. Some material has been reported from Galve, Spain.
Another species, P. dawsoni, was provisionally named by Woodward in 1891. This came from the county of Sussex, which is further east along the English coast. It was subsequently damaged and there seems not to have been a scientific description. In 1859, von Pleninger apparently used the name P. falconi. I have no idea what he was referring to.
Reference:

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 [1] (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)