Mastodon

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This article is about the animal. For other uses, see Mastodon (disambiguation).
"Mammut" redirects here. For other uses, see Mammut (disambiguation).
Mastodon
Temporal range: Late Miocene - Late Pleistocene, 5.3–0.011Ma
Mounted M. americanum skeleton, AMNH
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Proboscidea
Family: †Mammutidae
Genus: †Mammut
Blumenbach, 1799
Type species
†Elephas americanus
Kerr, 1792
Species
  • M. americanum (Kerr, 1792)
  • M. matthewi Osborn, 1921
  • M. raki Frick, 1933
  • M. cosoensis Schultz, 1937
Synonyms
  • Mastodon Cuvier, 1817
  • Tetracaulodon Godman, 1830
  • Missourium Koch, 1840
  • Leviathan Koch, 1841 (Emend. Koch, 1843)
  • Pliomastodon Osborn, 1926

Mastodons (Greek: μαστός "breast" and ὀδούς, "tooth") are an extinct group of mammal species related to elephants, that inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of the Pleistocene 10,000 to 11,000 years ago.[1] Their genus name is Mammut, and they are members of the order Proboscidea. They lived in herds and were predominantly forest dwelling animals that fed on a mixed diet of browsing and grazing with a seasonal preference for browsing, in contrast to living elephants that are mostly grazing animals.

The American mastodon is the most recent and best-known species of the genus. They disappeared from North America as part of a mass extinction of most of the Pleistocene megafauna, widely presumed to have been a result of rapid climate change in North America, as well as the sophistication of stone tool weaponry used by the Clovis hunters which may have caused a gradual attrition of the mastodon population.

Etymology

American mastodon molars at the State Museum of Pennsylvania

The name Mastodon (or mastodont) means nipple tooth (Greek: μαστός "nipple" and ὀδούς, "tooth"),[2][3] and was assigned by the French anatomist George Cuvier, derived from the cone-shaped cusps of their tooth which resembles the shape of nipples. Mastodon as a genus name is obsolete;[4] the valid name is Mammut, a name that preceded Cuvier's description, making Mastodon a junior synonym. The change was met with resistance, and authors sometimes applied "Mastodon" as an informal name so it became the common term for members of the genus.

Description

Mastodons were similar in appearance to elephants and mammoths, though not closely related. Compared to mammoths, mastodons had shorter legs, a longer body and were more heavily muscled,[5] a build similar to that of the current Asian elephants. The average body size of the species M. americanum was around 2.3 m (7 ft 7 in) in height at the shoulders, corresponding to a large female or a small male, but large males could grow up to 2.8 m (9 ft 2 in)[6] in height and weigh as much as 4.5 tonnes (5 short tons).[7] Like modern elephants, the females were smaller than the males. They had a low and long skull with long curved tusks,[8] with those of the males being more massive and more strongly curved.[6] Mastodons had cusp-shaped teeth, different from mammoth and elephant teeth (which have a series of enamel plates), well-suited for chewing leaves and branches of trees and shrubs.[7]

Discovery

The first remains of Mammut were found in the village of Claverack, New York, in 1705, a tooth some 2.2 kilograms (5 lb) in weight, which became known as the “incognitum”. Some time later, similar remains were found in South Carolina, which according to the slaves, looked remarkably similar to those of African elephants, soon followed discoveries of complete bones and tusks in Ohio, and people started referring to the "incognitum" as a mammoth, like the ones that were being dug out in Siberia. Anatomists noted that the teeth of mammoth and elephants were different from those of incognitum, which possessed rows of large conical cusps, indicating that they were dealing with a distinct species.[9]

Classification and species

Comparison of Woolly mammoth (L) and American mastodon (R)

Mammut is a genus of the extinct family Mammutidae, related to the proboscidean family Elephantidae (mammoths and elephants) from which it originally diverged approximately 27 million years ago.[10] The following cladogram shows the placement of the American mastodon among other proboscideans, based on hyoid characteristics:[11]


Mammut americanum (American mastodon)

Gomphotherium sp.

Stegodon zdanskyi

Loxodonta africana (African elephant)

Elephas maximus (Asian elephant)

Mammuthus columbi (Columbian mammoth)








Over the years, several fossils from localities in North America, Africa and Asia have been attributed to Mammut, but only the North American remains have been named and described, one of them being M. furlongi, named from remains found in the Juntura Formation of Oregon, dating from the late Miocene.[12] However, it is no longer considered valid,[13] leaving only 4 valid species left.

M. matthewi: Found in the Snake Creek Formation of Nebraska, dating from the late Hemphillian. Some authors consider it practically undistinguishable from M. americanum.[14]

M. raki: Its remains were found in the Palomas Formation, nearby Truth or Consequences, New Mexico, dating from the early-middle Pliocene, between 4.5-3.6 Ma.[15] It coexisted with Equus simplicidens and Gigantocamelus and differs from M. americanum in having a relatively longer and narrower third molar,[14] similar to the description of the defunct genus Pliomastodon which supports its arrangement as an early species of Mammut.[16] However, like M. matthewi, some authors don't consider it sufficiently distinct from M. americaum to warrant its own species.

M. cosoensis: Found in the Coso Formation of California, dating from the late Pliocene, originally a species of Pliomastodon[17] it was later assigned to Mammut.[18]

M. americanum: The American mastodon, the most known and the last species of Mammut, its earliest occurrences date from the early-middle Pliocene (early Blancan stage). It had a continent wide distribution, specially during the Pleistocene epoch,[14] known from fossil sites ranging from present-day Alaska and New England in the north, to Florida, southern California, and as far south as Honduras.[19] The American mastodon resembled a woolly mammoth in appearance, with a thick coat of shaggy hair.[20] It had tusks that sometimes exceeded five meters in length; they curved upwards, but less dramatically than those of the woolly mammoth.[21] Its main habitat was cold spruce woodlands, and it is believed to have browsed in herds.[20] It became extinct at the end of the Pleistocene approximately 11,000 years ago.\

A complete mtDNA sequence has been obtained from the tooth of an M. americanum skeleton found in permafrost in northern Alaska.[22] The remains are thought to be 50 to 130 Ma old. This sequence has been used as an outgroup to refine divergence dates in the evolution of the Elephantidae.[22] The rate of mtDNA sequence change in proboscideans was found to be significantly lower than in primates.

Paleobiology

Social behavior

Female and calf American mastodon at the George Page Museum.

Based on the characteristics of mastodon bonesites we can infer that, like in modern proboscideans, the Mastodon social group consisted of adult females and young, living in bounded groups called mixed herds. The males abandoned the mixed herds once reaching sexual maturity and lived either alone or in male bond groupings. Unlike modern elephants, the evidence suggest that there probably was no seasonal synchrony of mating activity, with both males and females seeking out each other for mating when sexually active.[23]

Range and habitat

Restoration of a herd by Charles R. Knight

The range of most species of Mammut is unknown as their occurrences are restricted to few localities, the exception being the American mastodon (M. americanum), which is one of the most widely distributed Pleistocene proboscideans in North America, ranging in age from the faunal stages of Blancan to Rancholabrean and with fossil sites from as north as Alaska, as east as Florida and as south as the state of Puebla in central Mexico,[19] however there is an isolated record from Honduras, probably reflecting the results of the maximum expansion achieved by the American mastodon during the Late Pleistocene. There is strong evidence to support that the members of Mammut were forest dwelling proboscideans, predominating in woodlands and forests,[23] feeding in sylvan vegetation.[8] They apparently did not disperse southward to South America, it is speculated this was because of a dietary specialization on a particular type of vegetation.[24]

Diet

Mastodons have been characterized as predominantly browsing animals, most accounts of gut contents have identified coniferous twigs as the dominant element in their diet, in other accounts (Burning tree mastodon) have found no coniferous content and suggest selective feeding on low, herbaceous vegetation, implying a mixed browsing and grazing diet,[25] evidence supported by studies of isotopic bone chemistry but displaying a seasonal preference for browsing.[26]

Extinction

They are generally reported as having disappeared from North America about 10,500 years ago[1] as part of a mass extinction of most of the Pleistocene megafauna, widely presumed to have been as a result of human hunting pressure.[27][28] The latest Paleo-Indians entered the American continent and expanded to relatively large numbers 13,000 years ago,[29] and their hunting may have caused a gradual attrition of the mastodon population.[30][31] Analysis of tusks of mastodons from the American Great Lakes region over a span of several thousand years prior to their extinction in the area shows a trend of declining age at maturation; this is contrary to what one would expect if they were experiencing stresses from an unfavorable environment, but is consistent with a reduction in intraspecific competition that would result from a population being reduced by human hunting.[31]

See also

References

  1. ↑ 1.0 1.1 Fiedal, Stuart (2009). "Sudden Deaths: The Chronology of Terminal Pleistocene Megafaunal Extinction". In Haynes, Gary. American Megafaunal Extinctions at the End of the Pleistocene. Springer. pp. 21–37. doi:10.1007/978-1-4020-8793-6_2. ISBN 978-1-4020-8792-9. 
  2. ↑ mastodon Online Etymology Dictionary Retrieved 10 November 2012
  3. ↑ mastodon Merriam-Webster Retrieved 30 June 2012
  4. ↑ Agusti, Jordi and Mauricio Anton (2002). Mammoths, Sabretooths, and Hominids. New York: Columbia University Press. p. 106. ISBN 0-231-11640-3. 
  5. ↑ Lange, I.M. (2002). Ice Age Mammals of North America: A Guide to the Big, the Hairy, and the Bizarre (illustrated ed.). Mountain Press Publishing. pp. 166–168. ISBN 0878424032. 
  6. ↑ 6.0 6.1 Woodman, N. (2008). "The Overmyer Mastodon (Mammut americanum) from Fulton County, Indiana". The American Midland Naturalist 159 (1): 125–146. doi:10.1674/0003-0031(2008)159[125:TOMMAF]2.0.CO;2. 
  7. ↑ 7.0 7.1 Sullivan, Robert M. (2010). "Rising from the muck: The Marshalls Creek mastodon". Pennsylvania Heritage. 
  8. ↑ 8.0 8.1 Lucas, Spencer G.; Guillermo E. Alvarado (2010). "Fossil Proboscidea from the Upper Cenozoic of Central America: Taxonomy, Evolutionary and Pelobiogeographic Significance". Revista Geológica de América Central. 42: 9–42. ISSN 0256-7024. 
  9. ↑ Conniff, Richard (April 2010). "Mammoths and Mastodons: All American Monsters". Smithsonian Magazine. Retrieved 23 December 2012. 
  10. ↑ Shoshani, J.; Walter, R. C.; Abraha, M.; Berhe, S.; Tassy, P.; Sanders, W. J.; Marchant, G. H.; Libsekal, Y.; Ghirmai, T.; Zinner, D. (2007-07-24). "A proboscidean from the late Oligocene of Eritrea, a "missing link" between early Elephantiformes and Elephantimorpha, and biogeographic implications". Proceedings of the National Academy of Sciences 103 (46): 17296–17301. Bibcode:2006PNAS..10317296S. doi:10.1073/pnas.0603689103. ISSN 0027-8424. 
  11. ↑ Shoshani, J.; Tassy, P. (2005). "Advances in proboscidean taxonomy & classification, anatomy & physiology, and ecology & behavior". Quaternary International. 126–128: 5. Bibcode:2005QuInt.126....5S. doi:10.1016/j.quaint.2004.04.011. 
  12. ↑ Shotwell, J.A; D.E., Russell (1963). "Mammalian fauna of the upper Juntura Formation, the black butte local fauna. in The Juntura Basin: Studies in Earth History and Paleoecology". Transactions of the American Philosophical Society 53 (1): 77. 
  13. ↑ Lambert, W.D. (1998). Proboscidea. In: Janis, C.M., Scott, K.M., Jacobs, L.L. (Eds.), Evolution of Tertiary Mammals of North America, Terrestrial Carnivores, Ungulates and Ungulatelike Mammals, vol. 1. (Shoshani, J. ed.). Cambridge: Cambridge University Press. pp. 606–621. 
  14. ↑ 14.0 14.1 14.2 Ruez, D. R. (2007). "Chapter 4: Revision of the blancan mammals from Hagerman fossil beds, National monument, Idaho". Effects of Climate Change on Mammalian Fauna Composition and Structure During the Advent of North American Continental Glaciation in the Pliocene. ProQuest. pp. 249–252. ISBN 0549266593. 
  15. ↑ Morgan, Gary S.; Spencer G. Lucas (2001). "Summary of Blancan and Irvingtonian (Pliocene and early Pleistocene) Mammalian Biochronology of New Mexico" (PDF). New Mexico Bureau of Mines and Mineral Resources Open-File Report 454B: 29–32. 
  16. ↑ Lucas, Spencer G.; Gary S. Morgan, (February 1999). "The oldest Mammut (Mammalia: Proboscidea) from New Mexico". New Mexico Geology: 10–12. 
  17. ↑ Schultz, J. R. (1937). "A Late Cenozoic Vertebrate Fauna from the Coso Mountains, Inyo County, California". Carnegie Institution of Washington Publication 483 (3): 77–109. 
  18. ↑ Jeheskel Shoshani; Pascal Tassy (1996). "Summary, conclusions, and a glimpse into the future". The Proboscidea: Evolution and Palaeoecology of Elephants and Their Relatives (illustrated ed.). Oxford University Press. pp. 335–348. ISBN 0198546521. 
  19. ↑ 19.0 19.1 Polaco, O. J.; Arroyo-Cabrales, J.; Corona-M., E.; López-Oliva, J. G. (2001). "The American Mastodon Mammut americanum in Mexico". In Cavarretta, G.; Gioia, P.; Mussi, M. et al. The World of Elephants - Proceedings of the 1st International Congress, Rome October 16–20, 2001. Rome: Consiglio Nazionale delle Ricerche. pp. 237–242. ISBN 88-8080-025-6. Retrieved 2008-07-25. 
  20. ↑ 20.0 20.1 Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 243. ISBN 1-84028-152-9. 
  21. ↑ Kurtin, Bjvrn; Björn Kurtén Elaine Anderson (1980). Pleistocene Mammals of North America (illustrated ed.). Columbia University Press. p. 345. ISBN 0231037333. 
  22. ↑ 22.0 22.1 Proboscidean Mitogenomics: Chronology and Mode of Elephant Evolution Using Mastodon as Outgroup. Jul 24, 2007. doi:10.1371/journal.pbio.0050207.st004. 
  23. ↑ 23.0 23.1 Haynes, G.; Klimowicz, J. (2003). "Mammoth (Mammuthus spp.) and American mastodont (Mammut americanum) bonesites: what do the differences mean?". Advances in Mammoth Research 9: 185–204. 
  24. ↑ Prado et al. (2005). "The Pleistocene Gomphotheriidae (Proboscidea) from South America". Quaternary International 126 (128): 21–30. Bibcode:2005QuInt.126...21P. doi:10.1016/j.quaint.2004.04.012. 
  25. ↑ Lepper et al. (1991). "Intestinal Contents of a late Pleistocene Mastodont from Midcontinental North America". Quaternary Research 36: 120–125. Bibcode:1991QuRes..36..120L. doi:10.1016/0033-5894(91)90020-6. 
  26. ↑ Fisher, D. C. (1996). "Extinction of Proboscideans in North America". In Shoshani, J. & Tassy, P. The Proboscidea: Evolution and Palaeoecology of Elephants and Their Relatives. Oxford, UK: Oxford University Press. pp. 296–315. 
  27. ↑ Martin, P. S. (2005). "Chapter 6, Deadly Syncopation". Twilight of the Mammoths: Ice Age Extinctions and the Rewilding of America. University of California Press. pp. 118–128. ISBN 0-520-23141-4. 
  28. ↑ Burney, D. A.; Flannery, T. F. (July 2005). "Fifty millennia of catastrophic extinctions after human contact". Trends in Ecology & Evolution (Elsevier) 20 (7): 395–401. doi:10.1016/j.tree.2005.04.022. PMID 16701402. Retrieved 2009-06-12. 
  29. ↑ Beck, Roger B.; Linda Black, Larry S. Krieger, Phillip C. Naylor, Dahia Ibo Shabaka, (1999). World History: Patterns of Interaction. Evanston, Illinois: McDougal Littell. ISBN 0-395-87274-X. 
  30. ↑ Ward, Peter (1997). The Call of Distant Mammoths. Springer. p. 241. ISBN 978-0-387-98572-5. 
  31. ↑ 31.0 31.1 Fisher, Daniel C. (2009). "Paleobiology and Extinction of Proboscideans in the Great Lakes Region of North America". In Haynes, Gary. American Megafaunal Extinctions at the End of the Pleistocene. Springer. pp. 55–75. doi:10.1007/978-1-4020-8793-6_4. ISBN 978-1-4020-8792-9. 

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