Paramys

Paramys
Temporal range: Late Paleocene - Middle Eocene
Skull
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Suborder: Sciuromorpha
Infraorder: Protrogomorpha
Family: †Ischyromyidae
Genus: †Paramys
Leidy, 1871
Species
  • P. adamus
  • P. atavus
  • P. compressidens
  • P. copei
  • P. delicatior
  • P. delicatus
  • P. excavatus
  • P. hunti
  • P. nini
  • P. pycnus
  • P. simpsoni
  • P. taurus

Paramys is an extinct genus of rodents from North America, Europe, and Asia. It is one of the oldest genera of rodents known and probably lived in trees. While the genus name literally means "near a mouse", it coexisted with Thisbemys, a similar rodent, thus yielding a reference to Pyramus and Thisbe.

Description

The brain of both the Early Eocene P. copei and the Middle Eocene P. delicatus was characterised by a lower neocortical surface area, smaller paraflocculi, and larger olfactory bulbs relative to total endocranial volume of later rodents, and they both possessed encephalisation quotients higher than that of Ischyromys typus. The enamel in Paramys incisors was about 50 µm thick. Paramys incisor enamel had pauciserial Hunter-Schreger bands (HSBs) with about 2-3 enamel prisms per band. The interprismatic matrix ran parallel to enamel prisms.

Palaeobiology

Locomotion

P. delicatus possessed more robust limbs and could apply a greater mechanical advantage using its limbs relative to most living squirrels, including living semi-fossorial squirrels. This suggests that it was a semi-fossorial animal that was adapted for scratch-digging.

References

  1. ↑ "Glossary. American Museum of Natural History". Archived from the original on 20 November 2021.
  2. ↑ Bertrand, Ornella C.; Amador-Mughal, Farrah; Silcox, Mary T. (27 January 2016). "Virtual endocasts of Eocene Paramys (Paramyinae): oldest endocranial record for Rodentia and early brain evolution in Euarchontoglires". Proceedings of the Royal Society B: Biological Sciences. 283 (1823) 20152316. doi:10.1098/rspb.2015.2316. ISSN 0962-8452. PMC 4795019. PMID 26817776.
  3. ↑ Martin, Thomas (December 1993). "Early rodent incisor enamel evolution: Phylogenetic implications". Journal of Mammalian Evolution. 1 (4): 227–254. doi:10.1007/BF01041665. ISSN 1064-7554. Retrieved 4 October 2026 – via Springer Nature Link.
  4. ↑ Prufrock, Kristen A.; Ruff, Christopher B.; Rose, Kenneth D. (9 November 2020). "Locomotor Behavior and Body Mass of Paramys delicatus (Ischyromyidae, Rodentia) and Commentary on Other Early North American Paramyines". Journal of Mammalian Evolution. 28 (2): 435–456. doi:10.1007/s10914-020-09523-8. ISSN 1064-7554. Retrieved 10 July 2025 – via Springer Nature Link.

Further reading