Coendou, Aplodontia, Ratufa, Sciurus and Paramys

Paramys compressidens (Leidy 1871; Matthew 1910; middle Eocene, 45 mya) is one of the earliest known squirrel-like rodents, but others of its kind preceded the multituberculates, like Shenshou in the Late Jurassic. Manual digit 1 is absent. Compare to the extant Ratufa (above).

Coendou prehensilis (Lacépède 1799) is the extant prehensile-tailed porcupine. That marks it as primitive. This arboreal herbivore is protected by spine-like hairs.

Apolodontia compared to Paramys and Coendou

Aplodontia rufa (Rafinesque 1817) is the extant mountain beaver, not related to beavers or squirrels, but to porcupines, like Coendou, in the LRT. It is considered a 'living fossil' due to aa list of primitive traits. The short tail is a recent trait. They are nocturnal and can climb trees.

Ratufa indica (Erxleben 1777, extant, Indian giant squirrel, 36cm + 60cm tail) is an arboreal rodent and the largest living squirrel. Some species eat bird eggs and insects, but normal diet includes fruit, flowers, nuts and tree bark.

Sciurus vulgaris (Linneaus 1758; snout-vent length = 20cm + 20cm tail) is the extant red squirrel.

Glaucomys volans (Linneaus 1758; snout-vent length = 10cm +10cm tail) is the extant Southern flying squirrel convergent with basal flying multituberculates, like Vilevolodon. These are gliders, not flappers or fliers, as should be obvious.

Erxleben JCP 1777. Systema regni animalis per classes, ordines, genera, species, varietates cum synonymia et historia animalium. Classis I. Mammalia [Animal kingdom system by class, order, genus, species, varieties with synonyms and animals' history. Class I. Mammalia.] (in Latin). 42. Leipzig, Germany: Impensis Weygandianis.

de Lacépède BGE 1799. Tableau des divisions, sous-divisions, ordres et genres des mammifères. Paris: Plassan. [Originally issued as a pamphlet dated “L’An VII de la République”

Leidy J 1871. Remains of extinct mammals from Wyoming. Proceedings of the Academy of Natural Sciences 23: 113–116.

Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

Matthew WD 1910. On the osteology and relationships of Paramys and the affinities of the Ischyromyidae. Bulletin of the American Museum of Natural History, 28:43–72.

Rafinesque CS 1817. Descriptions of seven new genera of North American quadrupeds. American Monthly Magazine and Critical Review 2:44–46.

wiki/Paramys
wiki/Ratufa
wiki/Sciurus
wiki/Glaucomys
wiki/Coendou
wiki/Aplodontia