#caviomorpha

It hasn't been requested yet, I'll do the whole family!

Incamys bolivianus was a caviomorph rodent representing an early member of the chinchillid family, with its closest modern relatives being chinchillas and viscachas.

Living in what is now Bolivia and Argentina during the late Oligocene about 27 million years ago, it inhabited an arid open grassland at a time when the area's climate had drastically cooled due to the formation of the Antarctic Circumpolar Current.

It's estimated to have been similar in size to a large modern chinchilla – weighing around 700g (~1lb 8oz) and measuring about 25-30cm long not including the tail (~10-12").

An endocast of the shape of its brain from a near-complete fossil skull shows that it had a well-developed sense of hearing, particularly in vocalization processing, suggesting it may have been a social animal living in groups communicating with complex calls similar to modern chinchillids. It was probably a ground-dweller less agile than its modern relatives, but still capable of fast movements.

———

NixIllustration.com | Tumblr | Patreon

Capybara (Hydrochoerus hydrochaeris)

A young nutria rat at the Mönchbruch nature reserve in Kelsterbach, western Germany

Photograph: Dorothee Barth/DP/AFP/Getty

When Rodents Rafted Across the Ocean 

The best evidence we have suggests that, while Caviomorpha originated in South America, they came from ancestors in Africa, over 40 million years ago. So how did they get there? 

North American porcupine (Erethizon dorsatum)