ever, it was unrelated to elephants or tapirs, but was instead related to other extinct South American ungulates. Fossils have been dated from the Early to Middle Miocene.[2] Fossil remains of the type species A. magnus have been found in the Santa Cruz Formation in Argentina. Other fossils have been found in the Deseado, Sarmiento, and Aisol Formations of Argentina and Chile (Cura-Mallín Group).[2]
Description
Restoration and size comparison of A. magnus
Astrapotherium had an elongated body, with a total length around 2.5 m (8.2 ft), a weight of nearly 1,000 kg (2,200 lb), and relatively short limbs.[3] Larger estimates suggest its body mass was up to 1,600–3,500 kilograms (3,500–7,700 lb).[4] It had small plantigrade feet, and the hind limbs were significantly weaker than the fore limbs. Its four canine teeth were elongated to form short tusks, and it had broad, protruding lower incisors, which likely ground against a horny pad in the upper jaw, as in many modern ruminants.[3]
Canine tooth of A. magnus at the Museum für Naturkunde, Berlin
The nostrils were placed high on the head, which might indicate the presence of a trunk, but could equally be due to other reasons, such as an inflatable nasal cavity. [5]
Classification
Cladogram based in the phylogenetic analysis published by Vallejo-Pareja et al., 2015, showing the position of Astrapotherium:[6]
Eoastrapostylops
Trigonostylops
Tetragonostylops
Albertogaudrya
Scaglia
Astraponotus
Maddenia
Comahuetherium
Parastrapotherium
Astrapotheriinae
Astrapotherium
Astrapothericulus
Uruguaytheriinae
Uruguaytherium
Hilarcotherium
Xenastrapotherium
Granastrapotherium
Paleobiology
The animal was probably at least partially aquatic, living in shallow water and feeding on marsh plants in a similar manner to a modern hippopotamus.[3]
References
Alejandro Kramarz; Alberto Garrido; Mariano Bond (2019). "Astrapotherium from the Middle Miocene Collón Cura Formation and the decline of astrapotheres in southern South America". Ameghiniana. in press. Archived from the original on 2017-10-02. Retrieved 2019-07-24.
Astrapotherium at Fossilworks.org
Palmer, Douglas, ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 248. ISBN 1-84028-152-9.
Kramarz, Alejandro G.; Bond, Mariano (2008). "Revision of Parastrapotherium (Mammalia, Astrapotheria) and other Deseadan astrapotheres of Patagonia". Ameghiniana. 45 (3).
Wall, W. P. (1980). Cranial evidence for a proboscis in Cadurcodon and a review of snout structure in the family Amynodontidae (Perissodactyla, Rhinocerotoidea). Journal of Paleontology, 968-977.
Vallejo-Pareja, M. C.; Carrillo, J. D.; Moreno-Bernal, J. W.; Pardo-Jaramillo, M.; Rodriguez-Gonzalez, D. F.; Muñoz-Duran, J. (January 2015). "Hilarcotherium castanedaii, gen. et sp. nov., a new Miocene astrapothere (Mammalia, Astrapotheriidae) from the Upper Magdalena Valley, Colombia" (PDF). Journal of Vertebrate Paleontology. 35 (2): e903960. doi:10.1080/02724634.2014.903960. S2CID 130728894. Archived (PDF) from the original on 14 July 2019 – via the Colombian Geological Survey.
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