Paracimexomys
Scientific classification
Kingdom: Animalia
Therapsida
Class: Mammalia
Order: Multituberculata
Paracimexomys group
Genus: Paracimexomys
Species
  ?P. crossi
  P. magister
  P. magnus
  P. perplexus
  P. priscus
  P. robisoni

Ref.

Paracimexomys is an extinct mammal that lived during the Cretaceous period, so it shared the world with dinosaurs. It was a member of the also extinct order of Multituberculata.
Remains are not extensive and come from North America. Some Romanian fossils were also tentatively assigned to this genus, though that now seems doubtful.

Genus: Paracimexomys Archibald JD, 1982
'beside Cimexomys'
Aka: Cimexomys sp. Sloan & Van Valen, 1965
Remarks: P. fossils were originally referred to C., until it was realized they were different enough to justify a genus of their own.

Species: ?Paracimexomys crossi Cifelli RL, 1997
Place: Antlers Formation, Oklahoma
Country: USA
Age: Upper Aptian-Albian, Lower Cretaceous
Remarks: Based on a tiny tooth, this was the first reported Okie Mesozoic mammal. It's also the oldest known member of the informal Paracimexomys group. The species name honours the prison officer, Bobby Cross, who has found found this and other fossils.
Reference: Cifelli (1997), First notice on Mesozoic mammals from Oklahoma. Oklahoma Geology Notes, 57, p.4-17.

Species: Paracimexomys magister (Fox RC, 1971) Archibald JD, 1982
Aka: Cimexomys magister Fox, 1971
Place: Utah
Country: USA
Age: Upper Santonian, Upper Cretaceous
Remarks: When alive, the animal weighed probably about 100g, (about four mice).

Species: Paracimexomys magnus (Sahni A, 1972) Archibald JD, 1982
Aka: Cimexomys magnus Sahni A, 1972
Place: Judith River Formation, Montana
Country: USA
Age: Campanian, Upper Cretaceous
References: Sahni (1972), Bulletin of the American Museum of Natural History 147(6).
Archibald (1982), A study of Mammalia across the Cretaceous-Tertiary boundary in Garfield County, Montana. Univ. of Calif Publ Geol Sci 122 xvi, p. 1-286.

Species: Paracimexomys perplexus Eaton JG & Cifelli RL, 2001
Place: Cedar Mountain Formation, Utah
Country: USA
Age: Albian (late) - Cenomanian (early), Upper Cretaceous
Reference: Eaton & Cifelli (2001), Multituberculate mammals from near the Early-Late Cretaceous boundary, Cedar Mountain Formation, Utah. Acta Palaeontologica Polonica 46(4), p.453-518.

Species: Paracimexomys priscus (Lillegraven JA, 1969) Archibald JD, 1982
Aka: Cimexomys priscus Lillegraven JA, 1969
Place: Hell Creek, Montana
Country: USA
Age: Maastrichtian, Upper Cretaceous
Remarks: Found in 1966. The holotype is in the collection of Alberta University, where the name Cimexomys is favoured. A weight guestimate is 60g.
Reference: Archibald (1982), A study of Mammalia across the Cretaceous-Tertiary boundary in Garfield County, Montana. Univ. of Calif Publ Geol Sci 122 xvi, p.286.

Species: Paracimexomys robisoni Eaton JG & Nelson ME, 1991
Place: Cedar Mountain Formation, Utah
Country: USA
Age: Albian (late) - Cenomanian (early), Upper Cretaceous
Remarks: The type fossil is in the Oklahoma Museum of Natural History. This was a mouse-sized 25 grammer.
Reference: Eaton & Nelson (1991), Contributions to Geology, vol 29, no. 1.

Extra remarks: ?Paracimexomys bestia seems to have become Cedaromys bestia. I'm not sure what Paracimexomys? dacicus Grigorescu D & Hahn G. 1987 was! Judging purely by the authors, I wouldn't be surprised if this were the Romanian material, which may well have been subsequently renamed.

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

(This information has been derived from [1] MESOZOIC MAMMALS; 'basal' Cimolodonta, Cimolomyidae, Boffidae and Kogaionidae, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)