Toxodon platensis - right upper molar tooth (M2)

Specimen number: NHMUK PV M 16562

Specimen Link:

Taxon: Toxodon platensis

Description: Right upper molar tooth (M2)

Site: On the banks of the Carcarañá, a few miles distant from the Paraná cliffs at estancia Grondona (north of Rosario), next to the Villa La Ribera-Rosario-Santa Fe road, Santa Fe province, Argentina.

Age: Late Pleistocene i.e., between 126,000 and 11,700 years old; however, these specimens are probably around 65,000 to 30,000 years old

Collection: Found on 1st October 1833 by Charles Darwin

Comments: This specimen was important as it was an almost exact match for one of the tooth sockets on the skull collected by Darwin in Uruguay, which formed the type specimen for this species. Physical similarities between this tooth and the teeth of some rodents greatly influenced Darwin’s and Richard Owen’s thinking on what Toxodon was related to. We now know that Toxodon was not closely related to rodents at all.

Toxodon is an extinct herbivorous (plant eating) mammal from South America. It is often reconstructed to look like a cross between a hippopotamus and a rhinoceros, although it is not closely related to either. It was first described by Richard Owen based on specimens collected by Charles Darwin on the Voyage of the Beagle.

October 1st …I found a curious & large cutting tooth.

-- Keynes, R. D. 1988. Charles Darwin’s Beagle Diary. Cambridge University Press, Cambridge. Page 193.

October 1st.- We started by moonlight and arrived at the Rio Tercero by sunrise…By good fortune, I discovered a tooth embedded in a layer of rock marl, which was afterwards found exactly to fit the socket in the head of a strange animal, the Toxodon...

-- Voyages of the Adventure and Beagle. [1st ed.]. Darwin, C. 1839. Volume III. Journal and remarks 1832-1836, p. 146.

In ye R. Carcarana I got a tooth, which puzzles even my conjectures, it looks like an enormous gnawing one

-- Darwin, C. 1835. Extracts from letters addressed to Professor Henslow. Privately printed, Cambridge. Available via, p. 13. Letter to Henslow, 12.11.1833.

Cite this as

Pip Brewer, Kate Burton, Adrian Lister (2018). Dataset: Darwin's Fossil Mammals. Resource: Toxodon platensis - right upper molar tooth (M2). Natural History Museum Data Portal (

Retrieved: 13:42 19 Jun 2019 (GMT)

Additional Information

Last updated April 2, 2018
Created April 2, 2018
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