Mastodon

Mastodon
Temporal range: Late Miocene - Late Pleistocene, 5.3–0.011 Ma
Mounted M. americanum skeleton (the "Warren mastodon"), AMNH
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Class: Mammalia
Order: Proboscidea
Family: †Mammutidae
Genus: †Mammut
Blumenbach, 1799
Type species
†Elephas americanum
Kerr, 1792
Species
  • †M. americanum (Kerr, 1792)
  • †M. matthewi Osborn, 1921
  • †M. raki Frick, 1933
  • †M. cosoensis Schultz, 1937
The inferred range of Mammut (Eurasian range includes that of Zygolophodon borsoni, whose genus assignment is uncertain, and M. matthewi)
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 any species of extinct mammutid proboscideans in the genus Mammut, distantly 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] Mastodons lived in herds and were predominantly forest dwelling animals that fed on a mixed diet obtained by browsing and grazing with a seasonal preference for browsing, similar to living elephants.

M. americanum, the American mastodon, is the youngest 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 related to overexploitation by Clovis hunters, and possibly also to climate change.

Taxonomy

Exhuming the First American Mastodon, 1806 painting by Charles Willson Peale

The first remnant of Mammut, a tooth some 2.2 kg (5 lb) in weight, was discovered in the village of Claverack, New York, in 1705. The mystery animal became known as the "incognitum".[2] The first bones to be collected and studied scientifically were found in 1739 at Big Bone Lick State Park, Kentucky, by French soldiers, who carried them to the Mississippi River, from where they were transported to the National Museum of Natural History in Paris.[3] Some time later, similar teeth were found in South Carolina, which, according to the slaves, looked remarkably similar to those of African elephants. This was soon followed by discoveries of complete bones and tusks in Ohio; people started referring to the "incognitum" as a mammoth, like the ones that were being dug out in Siberia.[2] Anatomists noted that the teeth of mammoth and elephants were different from those of the "incognitum", which possessed rows of large conical cusps, indicating that they were dealing with a distinct species. In 1806 the French anatomist Georges Cuvier named the incognitum "mastodon".[2]

The name mastodon (or mastodont) means "breast tooth" (Ancient Greek: μαστός "breast" and ὀδούς, "tooth"),[4][5] and was assigned by the French naturalist Georges Cuvier in 1817, for the nipple-like projections on the crowns of its molars.

Mastodon as a genus name is obsolete;[6] 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; consequently it became the common term for members of the genus.

Species include:

M. americanum, the American mastodon, the best 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, especially during the Pleistocene epoch,[7] 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.[8] The American mastodon resembled a woolly mammoth in appearance, with a thick coat of shaggy hair.[9] It had tusks that sometimes exceeded 5 meters (16 ft) in length; they curved upwards, but less dramatically than those of the woolly mammoth.[10] Its main habitat was cold spruce woodlands, and it is believed to have browsed in herds.[9] It became extinct at the end of the Pleistocene approximately 11,000 years ago.

M. matthewi—found in the Snake Creek Formation of Nebraska, dating from the late Hemphillian.[11] Some authors consider it practically indistinguishable from M. americanum.[7] There is one report of it in China.[12]

M. raki—Its remains were found in the Palomas Formation, near Truth or Consequences, New Mexico, dating from the early-middle Pliocene, between 4.5 and 3.6 Ma.[13] It coexisted with Equus simplicidens and Gigantocamelus and differs from M. americanum in having a relatively longer and narrower third molar,[7] similar to the description of the defunct genus Pliomastodon, which supports its arrangement as an early species of Mammut.[14] However, like M. matthewi, some authors do not 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,[15] it was later assigned to Mammut.[16]

Since a tentative 1977 report of M. matthewi in China, there have been no reports of currently recognized Mammut species outside of North America according to Paleobiology database (which does not recognize M. borsoni).[17] However, the status of Mammut or Zygolophodon borsoni in the literature appears equivocal.[18][19]

Evolution

Comparison of woolly mammoth (L) and American mastodon (R)
Excavation of a specimen in a golf course in Heath, Ohio, 1989

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.[20] The following cladogram shows the placement of the American mastodon among other proboscideans, based on hyoid characteristics:[21]




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.[22] However, it is no longer considered valid,[23] leaving only four valid species.

A complete mtDNA sequence has been obtained from the tooth of an M. americanum skeleton found in permafrost in northern Alaska.[24][25] The remains are thought to be 50,000 to 130,000 years old. This sequence has been used as an outgroup to refine divergence dates in the evolution of the Elephantidae.[25] The rate of mtDNA sequence change in proboscideans was found to be significantly lower than in primates.

Description

Restoration of an American mastodon

Modern reconstructions based on partial and skeletal remains reveal that mastodons were very similar in appearance to elephants and, to a lesser degree, mammoths, though not closely related to either one. Compared to mammoths, mastodons had shorter legs, a longer body and were more heavily muscled,[26] 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) in height.[27] However, the 35-year-old specimen AMNH 9950 grew 2.89 metres (9.5 ft) tall and weighed 7.8 tonnes (7.7 long tons; 8.6 short tons), and another male grew 3.25 metres (10.7 ft) tall and weighed 11 tonnes (11 long tons; 12 short tons).[28]

American mastodon molars at the State Museum of Pennsylvania

Like modern elephants, the females were smaller than the males. They had a low and long skull with long curved tusks,[29] with those of the males being more massive and more strongly curved.[27] Mastodons had cusp-shaped teeth, very different from mammoth and elephant teeth (which have a series of enamel plates), well-suited for chewing leaves and branches of trees and shrubs.[30]

Paleobiology

Social behavior

Female and calf American mastodon at the George Page Museum

Based on the characteristics of mastodon bone sites, it can be inferred that, as in modern proboscideans, the mastodon social group consisted of adult females and young, living in bonded groups called mixed herds. The males abandoned the mixed herds once reaching sexual maturity and lived either alone or in male bond groupings. As in modern elephants,[31] there probably was no seasonal synchrony of mating activity, with both males and females seeking out each other for mating when sexually active.[32]

Diet

Mastodons have been characterized as predominantly browsing animals.[note 1] Most accounts of gut contents have identified coniferous twigs as the dominant element in their diet. Other accounts (Burning tree mastodon) have reported no coniferous content and suggest selective feeding on low, herbaceous vegetation, implying a mixed browsing and grazing diet,[34] with evidence provided by studies of isotopic bone chemistry indicating a seasonal preference for browsing.[35]

Distribution and habitat

Restoration of an American mastodon 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. M. americanum fossil sites range in time from the faunal stages of Blancan to Rancholabrean and in locations from as far north as Alaska, as far east as Florida, and as far south as the state of Puebla in central Mexico,[8] with an isolated record from Honduras, probably reflecting the results of the maximum expansion achieved by the American mastodon during the Late Pleistocene. A few isolated reports tell of mastodons being found along the east coast up to the New England region,[36][37] with high concentrations in the Mid-Atlantic region.[38][39] There is strong evidence indicating that the members of Mammut were forest dwelling proboscideans, predominating in woodlands and forests,[32] and browsed on trees and shrubs.[29] They apparently did not disperse southward to South America, it being speculated that this was because of a dietary specialization on a particular type of vegetation.[40]

Extinction

Fossil evidence indicates that mastodons probably disappeared from North America about 10,500 years ago[1] as part of a mass extinction of most of the Pleistocene megafauna that is widely presumed to have been a result of human hunting pressure.[41][42] The latest Paleo-Indians entered the Americas and expanded to relatively large numbers 13,000 years ago,[43] and their hunting may have caused a gradual attrition of the mastodon population.[44][45] 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.[45]

See also

Notes

  1. ↑ Browsing is a type of herbivory in which a herbivore (or, more narrowly defined, a folivore) feeds on leaves, soft shoots, or fruits of high growing, generally woody, plants such as shrubs.[33] This is contrasted with grazing, usually associated with animals feeding on grass or other low vegetation.

References

  1. 1 2 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. ISBN 978-1-4020-8792-9. doi:10.1007/978-1-4020-8793-6_2.
  2. 1 2 3 Conniff, Richard (April 2010). "Mammoths and Mastodons: All American Monsters". Smithsonian Magazine. Retrieved 23 December 2012.
  3. ↑ Kolbert, Elizabeth (2014). The sixth extinction : an unnatural history (First ed.). New York: Henry Holt and Co. pp. 25–26. ISBN 0805092994.
  4. ↑ mastodon Online Etymology Dictionary Retrieved 10 November 2012
  5. ↑ mastodon Merriam-Webster Retrieved 30 June 2012
  6. ↑ Agusti, Jordi & Mauricio Anton (2002). Mammoths, Sabretooths, and Hominids. New York: Columbia University Press. p. 106. ISBN 0-231-11640-3.
  7. 1 2 3 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.
  8. 1 2 Polaco, O. J.; Arroyo-Cabrales, J.; Corona-M., E.; López-Oliva, J. G. (2001). "The American Mastodon Mammut americanum in Mexico" (PDF). In Cavarretta, G.; Gioia, P.; Mussi, M.; Palombo, M. R. The World of Elephants - Proceedings of the 1st International Congress, Rome October 16–20, 2001 (PDF). Rome: Consiglio Nazionale delle Ricerche. pp. 237–242. ISBN 88-8080-025-6. Retrieved 2008-07-25.
  9. 1 2 Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 243. ISBN 1-84028-152-9.
  10. ↑ Kurtin, Bjvrn; Björn Kurtén Elaine Anderson (1980). Pleistocene Mammals of North America (illustrated ed.). Columbia University Press. p. 345. ISBN 0231037333.
  11. ↑ Osborn, H. F. (1936). Percy, M. R., ed. Proboscidea: A monograph of the discovery, evolution, migration and extinction of the mastodonts and elephants of the world. 1. New York: J. Pierpont Morgan Fund. doi:10.5962/bhl.title.12097.
  12. ↑ "Mammut matthewi in the Paleobiology Database". Fossilworks. Retrieved 2017-05-06.
  13. ↑ 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.
  14. ↑ Lucas, Spencer G.; Morgan, Gary S. (February 1999). "The oldest Mammut (Mammalia: Proboscidea) from New Mexico". New Mexico Geology: 10–12.
  15. ↑ 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.
  16. ↑ 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.
  17. ↑ "Mammut in the Paleobiology Database". Fossilworks. Retrieved 2017-02-20.
  18. ↑ Pickford, M. (May 2007). "New mammutid proboscidean teeth from the Middle Miocene of tropical and southern Africa". Paleontology of Africa. 42: 29–35. Retrieved 2017-02-21.
  19. ↑ Kalmykov, N. P.; Mashchenko, E. N. (2009). "The most northeastern find of the Zygodont Mastodon (Mammut, Proboscidea) in Asia" (PDF). Doklady Biological Sciences. 428 (1): 434–436. doi:10.1134/S0012496609050123.
  20. ↑ 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. ISSN 0027-8424. PMC 1859925 Freely accessible. PMID 17085582. doi:10.1073/pnas.0603689103.
  21. ↑ 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.
  22. ↑ 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.
  23. ↑ 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. Cambridge: Cambridge University Press. pp. 606–621.
  24. ↑ http://arctos.database.museum/guid/UAM:ES:2414 UAM:ES:2414]
  25. 1 2 "Proboscidean Mitogenomics: Chronology and Mode of Elephant Evolution Using Mastodon as Outgroup". Jul 24, 2007. doi:10.1371/journal.pbio.0050207.st004.
  26. ↑ 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.
  27. 1 2 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.
  28. ↑ Larramendi, A. (2016). "Shoulder height, body mass and shape of proboscideans" (PDF). Acta Palaeontologica Polonica. 61. doi:10.4202/app.00136.2014.
  29. 1 2 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.
  30. ↑ Sullivan, Robert M. (2010). "Rising from the muck: The Marshalls Creek mastodon". Pennsylvania Heritage.
  31. ↑ Sukumar, R. (11 September 2003). The Living Elephants: Evolutionary Ecology, Behaviour, and Conservation. Oxford University Press, USA. p. 262. ISBN 978-0-19-510778-4. OCLC 935260783.
  32. 1 2 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.
  33. ↑ Chapman, J.L. and Reiss, M.J., Ecology: Principles and Applications. Cambridge, U.K.: Cambridge University Press, 1999. p. 304. (via Google books, Feb 25, 2008)
  34. ↑ Lepper, B. T.; Frolking, T. A.; Fisher, D. C.; Goldstein, G.; Sanger, J. E.; Wymer, D. A.; Ogden, J.G.; Hooge, P. E. (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.
  35. ↑ 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.
  36. ↑ "Northborough's Mastodon". Northborough MA Letterboxing. Retrieved July 8, 2014.
  37. ↑ "Prehistoric Massachusetts". The Paleontology Portal. Retrieved July 8, 2014.
  38. ↑ "Cohoes Mastodon". Cohoes.com. Retrieved July 8, 2014.
  39. ↑ "Prehistoric New York: Mastodons". Discovery Channel. Retrieved July 8, 2014.
  40. ↑ Prado, J. L.; Alberdi, M. T.; Azanza, B.; Sánchez, B.; Frassinetti, D. (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.
  41. ↑ 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. OCLC 58055404. Retrieved 2016-02-01.
  42. ↑ Burney, D. A.; Flannery, T. F. (July 2005). "Fifty millennia of catastrophic extinctions after human contact" (PDF). Trends in Ecology & Evolution. Elsevier. 20 (7): 395–401. PMID 16701402. doi:10.1016/j.tree.2005.04.022. Archived from the original (PDF) on 2010-06-10. Retrieved 2009-06-12.
  43. ↑ Beck, Roger B.; Black, Linda; Krieger, Larry S.; Naylor, Phillip C.; Shabaka, Dahia Ibo (1999). World History: Patterns of Interaction. Evanston, Illinois: McDougal Littell. ISBN 0-395-87274-X.
  44. ↑ Ward, Peter (1997). The Call of Distant Mammoths. Springer. p. 241. ISBN 978-0-387-98572-5.
  45. 1 2 Fisher, Daniel C. (2009). "Paleobiology and Extinction of Proboscideans in the Great Lakes Region of North America" (PDF). In Haynes, Gary. American Megafaunal Extinctions at the End of the Pleistocene. Springer. pp. 55–75. ISBN 978-1-4020-8792-9. doi:10.1007/978-1-4020-8793-6_4.
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