Taeniolabidoidea

Taeniolabidoidea is a group of extinct mammals known from North America and Asia. They were the largest members of the also extinct order called Multituberculata. Lambdopsalis even provides direct fossil evidence of mammalian fur, which isn't a bad state of preservation for a 60 million year old animal.

Some of these animals were macho-multis. Taeniolabis taoensis is the largest known multituberculate. It was about beaver-size and presumably beaver-heavy. That would mean up to about 30 kilos. In the individual generic entries, I shall employ the following highly specialized terms of my own concoction; heavyweight, super-heavyweight, sumo-heavyweight and sumo-super-heavyweight.

The group was initially established as a Suborder, before being assigned the rank of a Superfamily by McKenna & Bell, 1997, (see Kielan-Jaworowska & Hurum (2001) p.391-392). It's now strictly limited to the family Taeniolabididae, (with thanks to Dr Kielan-Jaworowska). Some of the fossils are well preserved. Catopsalis is known from the Upper Cretaceous of Canada, though the family's best represented from Paleocene strata.

Very technical details:
Derived characteristics of the taxon, (apomorphies), include: "snout short and wide with anterior part of zygomatic arches directed transversely, resulting in a square-like shape of the skull (shared with Kogaionidae); frontals small, pointed posteriorly, almost or completely excluded from the orbital rim," (Kielan-Jaworowska & Hurum 2001, p.417).

Page references: Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.
McKenna MC & Bell SK, (1997), Classification of Mammals Above the Species Level. Columbia University Press.

(This information has been 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)