The palaeobiogeography of South American gomphotheres

Gomphotheriid proboscideans reached South America as Late Cenozoic immigrants from North America. However, disagreements over alpha taxonomy, age dating and phylogenetic relationships have produced three competing hypotheses about this immigration: (1) a single gomphothere immigration took place soo...

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Main Author:	Spencer G. Lucas
Format:	Article
Language:	English
Published:	Springer 2013-01-01
Series:	Journal of Palaeogeography
Subjects:	gomphothere South America Cuvieronius Notiomastodon Haplomastodon Stegomastodon Amahuacatherium
Online Access:	http://www.sciencedirect.com/science/article/pii/S2095383615301292

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spelling	doaj-art-8b874ce00680483989927ee94c5d76072018-09-02T09:17:10ZengSpringerJournal of Palaeogeography2095-38362013-01-0121194010.3724/SP.J.1261.2013.00015The palaeobiogeography of South American gomphotheresSpencer G. LucasGomphotheriid proboscideans reached South America as Late Cenozoic immigrants from North America. However, disagreements over alpha taxonomy, age dating and phylogenetic relationships have produced three competing hypotheses about this immigration: (1) a single gomphothere immigration took place soon after the ~3 Ma closure of the Panamanian isthmus; (2) two separate gomphothere immigrations took place after closure of the isthmus; or (3) an earlier, Late Miocene (before 9 Ma) immigration brought gomphotheres into South America. A critical re-evaluation of the alpha taxonomy, age dating and phylogenetic relationships of Neotropical gomphotheres identifies two valid genera of South American gomphotheres, Cuvieronius and Notiomastodon (= “Haplomastodon”, = “Stegomastodon” from South America) and recognizes “Amahuacatherium” as an invalid genus likely based on a specimen of Notiomastodon. The oldest well-dated South American gomphothere fossil is Marplatan, ~2.5 Ma, from Argentina. The case for an age of “Amahuacatherium” older than 9 Ma is refuted by mammalian biostratigraphy and a re-evaluation of the relevant magnetostratigraphy. North American Rhynchotherium descended from Gomphotherium during the Late Hemphillian (~5–6 Ma) and gave rise to Cuvieronius in North America by the end of the Blancan (~2 Ma) time. Notiomastodon evolved from Cuvieronius in South America during the Pleistocene. The case for a close relationship between the Neotropical gomphotheres and Sinomastodon from China is rejected. Central America was not a center of endemic gomphothere evolution and merely acted as a pathway for the immigration of gomphotheres from north to south: Gomphotherium into Central America during the Miocene, Cuvieronius to Central America by Early Pleistocene time and on to South America. After closure of the Panamanian isthmus, Cuvieronius immigrated to South America, where it gave rise to Notiomastodon by Middle Pleistocene time. The South American history of gomphotheres was thus a modest evolutionary diversification from a single Plio-Pleistocene immigration.http://www.sciencedirect.com/science/article/pii/S2095383615301292gomphothereSouth AmericaCuvieroniusNotiomastodonHaplomastodonStegomastodonAmahuacatherium
institution	Open Data Bank
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language	English
format	Article
author	Spencer G. Lucas
spellingShingle	Spencer G. Lucas The palaeobiogeography of South American gomphotheres Journal of Palaeogeography gomphothere South America Cuvieronius Notiomastodon Haplomastodon Stegomastodon Amahuacatherium
author_facet	Spencer G. Lucas
author_sort	Spencer G. Lucas
title	The palaeobiogeography of South American gomphotheres
title_short	The palaeobiogeography of South American gomphotheres
title_full	The palaeobiogeography of South American gomphotheres
title_fullStr	The palaeobiogeography of South American gomphotheres
title_full_unstemmed	The palaeobiogeography of South American gomphotheres
title_sort	palaeobiogeography of south american gomphotheres
publisher	Springer
series	Journal of Palaeogeography
issn	2095-3836
publishDate	2013-01-01
description	Gomphotheriid proboscideans reached South America as Late Cenozoic immigrants from North America. However, disagreements over alpha taxonomy, age dating and phylogenetic relationships have produced three competing hypotheses about this immigration: (1) a single gomphothere immigration took place soon after the ~3 Ma closure of the Panamanian isthmus; (2) two separate gomphothere immigrations took place after closure of the isthmus; or (3) an earlier, Late Miocene (before 9 Ma) immigration brought gomphotheres into South America. A critical re-evaluation of the alpha taxonomy, age dating and phylogenetic relationships of Neotropical gomphotheres identifies two valid genera of South American gomphotheres, Cuvieronius and Notiomastodon (= “Haplomastodon”, = “Stegomastodon” from South America) and recognizes “Amahuacatherium” as an invalid genus likely based on a specimen of Notiomastodon. The oldest well-dated South American gomphothere fossil is Marplatan, ~2.5 Ma, from Argentina. The case for an age of “Amahuacatherium” older than 9 Ma is refuted by mammalian biostratigraphy and a re-evaluation of the relevant magnetostratigraphy. North American Rhynchotherium descended from Gomphotherium during the Late Hemphillian (~5–6 Ma) and gave rise to Cuvieronius in North America by the end of the Blancan (~2 Ma) time. Notiomastodon evolved from Cuvieronius in South America during the Pleistocene. The case for a close relationship between the Neotropical gomphotheres and Sinomastodon from China is rejected. Central America was not a center of endemic gomphothere evolution and merely acted as a pathway for the immigration of gomphotheres from north to south: Gomphotherium into Central America during the Miocene, Cuvieronius to Central America by Early Pleistocene time and on to South America. After closure of the Panamanian isthmus, Cuvieronius immigrated to South America, where it gave rise to Notiomastodon by Middle Pleistocene time. The South American history of gomphotheres was thus a modest evolutionary diversification from a single Plio-Pleistocene immigration.
topic	gomphothere South America Cuvieronius Notiomastodon Haplomastodon Stegomastodon Amahuacatherium
url	http://www.sciencedirect.com/science/article/pii/S2095383615301292
_version_	1612650761586475008

The palaeobiogeography of South American gomphotheres

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