Toxodon platensis - nearly complete cranium

Specimen number: NHMUK PV M 16560

Specimen Link:

Taxon: Toxodon platensis

Description: Nearly complete cranium (skull without the lower jaw) missing the teeth

Site: Banks of the Sarandi, adjacent to an estancia by the name of La Virgen de los Dolores. The latter was owned by Englishman George Keen and was located on the Bequeló, a stream near Mercedes, Uruguay.

Age: Late Pleistocene i.e., between 126,000 and 11,700 years old

Collection: Purchased on 26th November 1833 by Charles Darwin

Comments: This is the holotype specimen of Toxodon platensis. When a new species is proposed, a specimen is chosen to represent that species. This specimen is called the type specimen or holotype. Types are important specimens and it is the responsibility of museums such as the Natural History Museum (London) to care for these types and make them available for scientific study.

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.

The Toxodon, perhaps one of the strangest animals, ever discovered: in size it equalled an elephant or megatherium [an extinct giant ground sloth], but the structure of its teeth, as Mr. Owen states, proves indisputably that it was intimately related to the Gnawers [rodents], the order which, at the present day, includes most of the smallest quadrupeds: in many details it is allied to the Pachydermata [an obsolete term referring to animals with thick skins such as elephants, rhinoceroses, and hippopotamuses]: judging from the position of its eyes, ears and nostrils, it was probably aquatic, like the Dugong and Manatee, to which it is also allied. How wonderfully are the different Orders, at the present time so well separated, blended together in different points of the structure of the Toxodon!

-- Darwin, C. R. 1845. Journal of researches into the natural history and geology of the countries visited during the voyage of H.M.S. Beagle round the world, under the Command of Capt. Fitz Roy, R.N. 2nd edition. John Murray, London.

The head was found embedded in whitish earthy clay on the banks of a small stream which enters the Rio Negro, and is situated 120 miles to the N.W. of Monte Video. The head had been kept for a short time in a neighbouring farm-house as a curiosity, but when I arrived it was lying in the yard. I bought it for the value of eighteen-pence. The people informed me that when first discovered, about two years previously, it was quite perfect, but that the boys had since knocked out the teeth and had put it on a post as a mark to throw stones at. They showed me the spot where it had been found after a sudden flood had washed down part of the bank. Several fragments of bone and of an armadillo-like case were lying at the bottom of the almost dry watercourse. Some of these I collected, but from the disturbed state of the country the box in which they were packed was delayed on the road, and was afterwards sent direct to England.

-- Darwin, C. R. 1894. [Note on a Toxodon skull]. In R. Owen ed. The life of Richard Owen. London: John Murray, vol. 1, pp. 119-120.

Cite this as

Pip Brewer, Kate Burton, Adrian Lister (2018). Dataset: Darwin's Fossil Mammals. Resource: Toxodon platensis - nearly complete cranium. Natural History Museum Data Portal (

Retrieved: 06:58 27 Jun 2019 (GMT)

Additional Information

Last updated April 2, 2018
Created April 2, 2018
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