Megalonychidae

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Megalonychidae
Skeletal reconstruction of Megalonyx

Skeletal reconstruction of Megalonyx

Temporal occurrence
Oligocene to Pleistocene
23 million years to 10,000 years
Locations
Systematics
Higher mammals (Eutheria)
Sub-articulated animals (Xenarthra)
Tooth arms (pilosa)
Sloths (folivora)
Megatherioidea
Megalonychidae
Scientific name
Megalonychidae
Gervais , 1855

The Megalonychidae are an extinct mammal family from the group of sloths (Folivora). They include smaller and medium-sized members of the sloth, including giant sloths such as Megalonyx . The individual relatives were common in both South and Central and North America . The two-toed sloths ( Choloepus ) , which are still alive today, and some extinct forms of the West Indies were originally assigned to the family . However, according to molecular genetic studies, there are no closer relationships between these different groups of sloths and the Megalonychidae .

General

The earliest remains of the Megalonychidae family date from the early Oligocene (around 35 million years ago) and were found in Patagonia . With the creation of the Panamanian land bridge around 3 to 2.5 million years ago, the animals began to migrate north, one species, Nothrotheriops shastensis , even reached the Yukon River in Canada . Over time, the members of the family grew larger and larger, the largest animals being those of the genus Megalonyx of the Pleistocene .

Systematics

Historical

In the history of research, the Megalonychidae were considered to be a very diverse group, which not only included the representatives of continental America, but also the Caribbean sloths plus the still existing genus of the two-toed sloths ( Choloepus ). Significantly responsible for this were skeletal anatomical studies from 2004, which were among the most extensive on sloths to date. Similarities were found in the structure of the teeth, for example through the enlarged canine or incisor-like ( canini or incisive ) foremost tooth and the square to rounded rear molar-like ( molar-shaped ) teeth, each with two transverse ridges that are not completely parallel. Further similarities were found in the design of the snout. The two-toed sloths were considered to be particularly closely related to the Caribbean forms. Ross DE MacPhee and Jennifer L. White in particular dealt with the latter and their complex systematics in 2000 and 2001.

Even early molecular genetic studies from the turn of the 20th to the 21st century raised doubts about these relationships, but the number of species analyzed was too small for a more precise assessment. Much more extensive studies from 2019, both genetic and protein-based , then showed that the Megalonychidae are polyphyletic in their generally accepted definition . Accordingly, the Megalonychidae in the narrower sense are limited to Megalonyx and its closer relationship in continental America. They have closer relationships with the Megatheriidae and form part of the superfamily of the Megatherioidea . The Caribbean sloths represent a very early branch within the suborder, which had already split off from the other lines in the transition from the Eocene to the Oligocene around 35 million years ago and forms a homogeneous group. This is supported, among other things, by fossils from Puerto Rico already known from this period . The Caribbean sloths are therefore grouped together in the superfamily of the Megalocnoidea . The two-toed sloths, on the other hand, are close to the Mylodontidae and have been moved to the superfamily of the Mylodontoidea .

Overview of the genera of the Megalonychidae

The Megalonychidae are divided into several subfamilies and tribes. The mainly Late Miocene forms from South America are discussed in various articles by Diego Brandoni . In this perspective and taking into account further new descriptions, the following genera are distinguished:

  • Family Megalonychidae Gervais , 1855
  • Deseadognathus Carlini & Scillato-Yané , 2004
  • Zacatzontli McDonald & Carranza-Castañeda , 2017
  • Urumacocnus Rincón, Solórzano, McDonald & Montellano-Ballesteros , 2018
  • Pattersonocnus Rincón, Solórzano, McDonald & Montellano-Ballesteros , 2018
  • Ahytherium Cartelle, De Iuliis & Pujos , 2008
  • Australonyx De Iuliis, Pujos & Cartelle , 2009
  • Megistonyx McDonald, Rincón & Gaudin , 2013
  • Nohochichak McDonald & Chatters & Gaudin , 2017
  • Xibalbaonyx Stinnesbeck, Frey, Olguín, Stinnesbeck, Zell, Mallison, González, Núñez, Morlet, Mata, Sanvicente, Hering & Sandoval , 2017

literature

  • Ronald Nowak: Walker's Mammals of the World. Johns Hopkins University Press, Baltimore 1999, ISBN 0-80-185789-9

Individual evidence

  1. ↑ Timothy J. Gaudrin: Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): the craniodental evidence. Zoological Journal of the Linnean Society 140, 2004, pp. 255-305
  2. ↑ Ross DE MacPhee, Jennifer L. White and Charles A. Wood: New Megalonychid Sloths (Phyllophaga, Xenarthra) from the Quaternary of Hispaniola. American Museum Novitates 3303, 2000, pp. 1-32
  3. ↑ Jennifer L. White and Ross DE MacPhee: The sloths of the West Indies: A systematic and phylogentic review. In: Charles A. Woods and Florence E. Sergile (Eds.): Biogeography of the West Indies: Patterns and Perspectives, Second Edition. Boca-Raton, London, New York, washington, 2001, pp. 201-236
  4. ^ Matthias Höss, Amrei Dilling, Andrew Currant and Svante Pääbo: Molecular phylogeny of the extinct ground sloth Mylodon darwinii. Proceedings of the National Academy of Sciences 93, 1996, pp. 181-185
  5. ↑ Alex D. Greenwood, Jose Castresana, Gertraud Feldmaier-Fuchs and Svante Pääbo: A Molecular Phylogeny of Two Extinct Sloths. Molecular Phylogenetics and Evolution 18 (1), 2001, pp. 94-103
  6. ↑ Hendrik Poinar, Melanie Kuch, Gregory McDonald, Paul Martin and Svante Pääbo: Nuclear Gene Sequences from a Late Pleistocene Sloth Coprolite. Current Biology 13, 2003, pp. 1150-1152
  7. ↑ Michael Hofreiter, Julio L. Betancourt, Alicia Pelliza Sbriller, Vera Markgraf and H. Gregory McDonald: Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina. Quaternary Research 59, 2003, pp. 364-378
  8. ^ Ross DE MacPhee and Manuel A. Iturralde-Vinent: Origin of the Greater Antillean Land Mammal Fauna, 1: New Tertiary Fossils from Cuba and Puerto Rico. American Museum Novitates 3141, 1995, pp. 1-31
  9. ↑ Frédéric Delsuc, Melanie Kuch, Gillian C. Gibb, Emil Karpinski, Dirk Hackenberger, Paul Szpak, Jorge G. Martínez, Jim I. Mead, H. Gregory McDonald, Ross DE MacPhee, Guillaume Billet, Lionel Hautier and Hendrik N. Poinar : Ancient mitogenomes reveal the evolutionary history and biogeography of sloths. Current Biology 29, 2019, doi: 10.1016 / j.cub.2019.05.043
  10. ↑ Samantha Presslee, Graham J. Slater, François Pujos, Analía M. Forasiepi, Roman Fischer, Kelly Molloy, Meaghan Mackie, Jesper V. Olsen, Alejandro Kramarz, Matías Taglioretti, Fernando Scaglia, Maximiliano Lezcano, José Luis Lanata, John Southon, Robert Feranec, Jonathan Bloch, Adam Hajduk, Fabiana M. Martin, Rodolfo Salas Gismondi, Marcelo Reguero, Christian de Muizon, Alex Greenwood, Brian T. Chait, Kirsty Penkman, Matthew Collins and Ross DE MacPhee: Palaeoproteomics resolves sloth relationships. Nature Ecology & Evolution 3, 2019, doi: 10.1038 / s41559-019-0909-z
  11. ↑ a b Malcolm C. McKenna and Susan K. Bell: Classification of mammals above the species level. Columbia University Press, New York, 1997, pp. 1-631 (pp. 99-102)
  12. ↑ Diego Brandoni: Nuevos materiales de Ortotheriinae (Xenarthra, Tardigrada, Megalonychidae) procedentes del "Mesopotamiense" (Mioceno tardío) de Entre Ríos. In: FG Aceñolaza (ed.): Temas de la Biodiversidad Fluvial del Litoral III. Insugeo, Miscelánea 17, 2008, pp. 11-20
  13. ↑ Diego Brandoni: On the Systematics of Ortotherium Ameghino (Xenarthra, Tardigrada, Megalonychidae) from the 'Conglomerado Osífero' (Late Miocene) of Argentina. Journal of Vertebrate Paleontology 30 (3), 2010, pp. 975-980
  14. Jump up ↑ Diego Brandoni: The Megalonychidae (Xenarthra, Tardigrada) from the late Miocene of Entre Ríos Province, Argentina, with remarks on their systematics and biogeography. Geobios 44, 2011, pp. 33-44
  15. ^ A b Diego Brandoni: A new genus of Megalonychidae (Mammalia, Xenarthra) from the Late Miocene of Argentinia. Revista Brasileira de Paleontologia 17 (1), 2014, pp. 33-42
  16. ^ Alfredo A. Carlini and Gustavo J. Scillato-Yané: The oldest Megalonychidae (Xenarthra: Tardigrada); phylogenetic relationships and an emended diagnosis of the family. New Yearbook for Geology and Paleontology Abhandlungen 233 (3), 2004, pp. 423–443
  17. ^ Cástor Cartelle, Gerardo De Iuliis and François Pujos: A new species of Megalonychidae (Mammalia, Xenarthra) from the Quaternary of Poc ¸o Azul (Bahia, Brazil). Comptes Rendus Palevol 7, 2008, pp. 335-346
  18. ^ Gerardo De Iuliis, François Pujos and Cástor Cartelle: A new ground sloth (Mammalia: Xenarthra) from the Quaternary of Brazil. Comptes Rendus Palevol 8, 2009, pp. 705-715
  19. ↑ H. Gregory McDonald, Ascanio D. Rincón and Timothy J. Gaudin: A new genus of megalonychid sloth (Mammalia, Xenarthra) from the Late Pleistocene (Lujanian) of Sierra de Perija, Zulia State, Venezuela. Journal of Vertebrate Paleontology 33 (5), 2013, pp. 1226-1238
  20. ^ H. Gregory McDonald and Oscar Carranza-Castañeda: Increased xenarthran diversity of the Great American Biotic Interchange: a new genus and species of ground sloth (Mammalia, Xenarthra, Megalonychidae) from the Hemphillian (late Miocene) of Jalisco, Mexico. Journal of Paleontology, 2017 doi: 10.1017 / jpa.2017.45
  21. ^ H. Gregory McDonald, James C. Chatters and Timothy J. Gaudin: A new genus of megalonychid ground sloth (Mammalia, Xenarthra) from the late Pleistocene of Quintana Roo, Mexico. Journal of Vertebrate Paleontology, 2017, p. E1307206 doi: 10.1080 / 02724634.2017.1307206
  22. ↑ Sarah R. Stinnesbeck, Eberhard Frey, Jerónimo Avíles Olguín, Wolfgang Stinnesbeck, Patrick Zell, Heinrich Mallison, Arturo González González, Eugenio Aceves Núñez, Adriana Velázquez Morlet, Alejandro Terrazas Mata, Martha Benavente Sanvicente, Fabio Heringoval and Carmen Xibalba Sandovalx oviceps, a new megalonychid ground sloth (Folivora, Xenarthra) from the Late Pleistocene of the Yucatán Peninsula, Mexico, and its paleobiogeographic significance. Paläontologische Zeitschrift 91 (2), 2017, pp. 245–271
  23. ↑ Ascanio D. Rincón, Andrés Solórzano, H. Gregory McDonald and Marisol Montellano-Ballesteros: Two new megalonychid sloths (Mammalia: Xenarthra) from the Urumaco Formation (late Miocene), and their phylogenetic affinities. Journal of Systematic Palaeontology, 2018 doi: 10.1080 / 14772019.2018.1427639

Web links

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