Xyronomys | |
---|---|
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | † Multituberculata |
Family: | † Neoplagiaulacidae |
Genus: | † Xyronomys J. K. Rigby, 1980 |
Species | |
X. swainae |
Xyronomys is an extinct genus of small mammals from the Paleocene of North America, with two described species. The genus lies within the extinct order Multituberculata within the suborder Cimolodonta and family Neoplagiaulacidae.
The species Xyronomys swainae (J. K. Rigby, 1980) was found in Torrejonian (Paleocene)-age strata of Swain Quarry in Wyoming, United States. Represented by a couple of teeth, this genus was originally assigned to Eucosmodontidae. Kielan-Jaworowska and Hurum (2001, p. 406) refer it to Neoplagiaulacidae on the basis of its possession of microprismatic enamel, i.e. the tooth enamel is built up from small prisms.
A second species Xyronomys robinsoni was found in Puercan (Lower Paleocene)-age strata of Colorado, USA and was named by Middleton and Dewar in 2004.
Material assigned to this genus has also been reported from Rav W-1 in Saskatchewan, Canada.
Multituberculata is an extinct taxon of rodent-like allotherian mammals that existed for approximately 166 million years, the longest fossil history of any mammal lineage. They eventually declined from the late Paleocene onwards, disappearing from the known fossil record in the late Eocene, though gondwanatheres lived into the Miocene, and may have been multituberculates. More than 200 species are known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism to jerboa-like hoppers. Multituberculates are usually placed as crown mammals outside either of the two main groups of living mammals—Theria, including placentals and marsupials, and Monotremata—but closer to Theria than to monotremes. Nonetheless, at least one study found a potential status as sister taxa to monotremes/Australosphenida.
Ptilodus is a genus of mammals from the extinct order of Multituberculata, and lived during the Paleocene in North America.
Cimolodonta is a taxon of extinct mammals that lived from the Cretaceous to the Eocene. They were some of the more derived members of the extinct order Multituberculata. They probably lived something of a rodent-like existence until their ecological niche was assumed by true rodents. The more basal multituberculates are found in a different suborder, "Plagiaulacida".
Cimexomys is an extinct North American mammal that lived from the Upper Cretaceous to the Paleocene. For a while, it shared the world with dinosaurs, but outlived them. It was a member of the extinct order Multituberculata and lies within the suborder Cimolodonta. It is perhaps a member of the Paracimexomys group, though it is not certain.
Catopsalis is a genus of extinct mammal from the Paleocene of North America. This animal was a relatively large member of the extinct order of Multituberculata. Most Multituberculates were much smaller.
Neoplagiaulax is a mammal genus from the Paleocene of Europe and North America. In the case of the latter continent, there may possibly be some slightly earlier, Upper Cretaceous material too. It existed in the age immediately following the extinction of the last dinosaurs. This animal was a member of the extinct order Multituberculata, lying within the suborder Cimolodonta and family Neoplagiaulacidae.
Cernaysia is an extinct genus of mammal from the Paleocene of France and the United States. It existed in the age immediately following the extinction of the last dinosaurs. This animal was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Neoplagiaulacidae.
Krauseia is an extinct genus of small mammal from the Paleocene of North America. It was a member of the extinct order Multituberculata and is within the suborder of Cimolodonta, family Neoplagiaulacidae. The genus was nemed by Vianey-Liaud M. in 1986, and has also partly been known under the name Parectypodus.
Mesodma is an extinct genus of mammal, a member of the extinct order Multituberculata within the suborder Cimolodonta, family Neoplagiaulacidae. It lived during the upper Cretaceous and Paleocene Periods of what is now North America.
Mimetodon is a small mammal from the Paleocene of North America and perhaps Europe. It was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Neoplagiaulacidae.
Parectypodus is an extinct genus of mammals that lived from Late Cretaceous (Maastrichtian) to Eocene time in North America. It is a member of the extinct order of Multituberculata, suborder Cimolodonta, family Neoplagiaulacidae. It was named by G.L. Jepsen in 1930.
Xanclomys is a small mammal from the Paleocene of North America. It was a genus within the extinct order Multituberculata within the suborder Cimolodonta and family Neoplagiaulacidae.
Baiotomeus is a genus of mammals from the extinct order of Multituberculata. It is known from the Paleocene of North America.
Prochetodon is a genus of mammals from the extinct order Multituberculata. It lived during the Upper Paleocene and the Lower Eocene in North America. The genus was formally named by G. L. Jepsen in 1940.
Anconodon is an extinct genus of mammal from the Paleocene of North America, and thus lived just after the "age of the dinosaurs". It was a member of the extinct order Multituberculata within the suborder Cimolodonta and possibly the family Cimolodontidae.
Eucosmodon is a genus of extinct mammal from the Paleocene of North America. It is a member of the extinct order of Multituberculata within the suborder of Cimolodonta, and the family Eucosmodontidae. This genus has partly also been known as Neoplagiaulax. All known fossils of this small mammal are restricted to teeth.
Stygimys is an extinct mammal genus from the Upper Cretaceous and Paleocene of North America. It was a member of the extinct order Multituberculata within the suborder Cimolodonta, family Eucosmodontidae.
Microcosmodon is a mammal genus from the Paleocene of North America. It was a member of the extinct order Multituberculata, and lies within the suborder Cimolodonta and family Microcosmodontidae. The genus Microcosmodon was named by G.L. Jepsen in 1930.
Pentacosmodon is a mammal genus from the Paleocene of North America, so it lived somewhat after the "age of the dinosaurs". It was a member of the extinct order Multituberculata. It's within the suborder Cimolodonta and family Microcosmodontidae.
Hainina is an extinct mammal genus from the latest Cretaceous to the Paleocene of Europe.