Eremotherium

Eremotherium is an extinct genus of ground sloth of the family Megatheriidae, endemic to northern South America, Central America, and parts of southern North America during the Pleistocene epoch. It lived from 4.9 mya —11,000 years ago existing (as a genus) for approximately 4.889 million years .[1] Several species of Eremotherium were among the largest known ground sloths, rivalling Megatherium americanum in size, with E. rusconi reaching a length up to 6 m (20 ft) and a weight of more than 3 tonnes.[2] Eremotherium arrived in North America during the Late Pliocene or earliest Pleistocene during the Great American Interchange, with remains of E. eomigrans in Florida dating to the late Blancan, around 2.2 to 1.9 Ma.[3]

Eremotherium
Temporal range: Early Pliocene - Early Holocene, 4.9–0.011 Ma
↓
E. laurillardi at the HMNS
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Superorder:
Xenarthra
Order:
Pilosa
Family:
†Megatheriidae
Subfamily:
†Megatherinae
Tribe:
†Megatheriini
Subtribe:
†Megatheriina
Genus:
†Eremotherium

Spillmann, 1948
Species
  • E. laurillardi Lund 1842
  • E. eomigrans De Iullis & Cartelle 1999
  • E. rusconi (Schaub 1935)

Life history

Carbon isotopes and stereomicrowear analysis suggest that an individual from the Late Pleistocene (34,705-33,947 cal yr BP), of Goiás, Brazil, was a mixed feeder, suggesting a high proportion of shrubs and trees, this is in contrast to the presumed diet from specimens from Northeast Brazil, which had a diet of C4 herbaceous plants.[4] A 2020 discovery in Ecuador found 22 individuals ranging in age from juveniles to adults preserved together in anoxic marsh sediments, suggesting that Eremotherium may have been gregarious.[5]

Fossil distribution

Fossils have been uncovered from Volusia County, Florida, Chatham County, Georgia; Berkeley County, South Carolina; Espirito Santo; and Pedra Preta, Brazil; Tarapoto, Peru (giant form); Rio Canas, Ecuador.[6]

Taxonomy

Eremotherium was named by Austrian paleontologist Franz Spillmann (1948) and was assigned to Megatheriinae by Gaudin (1995); and to Megatheriidae by Franz Spillmann (1948), Carroll (1988) and Cisneros (2005).

Species
Eremotherium eomigrans skeleton in the North Carolina Museum of Natural Sciences.

E. eomigrans
Claw of Eremotherium eomigrans at MUSE - Science Museum in Trento

E. eomigrans was named by De Iulis and Cartelle (1999). E. eomigrans was assumed to have been restricted to Florida, as most fossil specimens have been recovered from that area. However, in 1993, another specimen was recovered in North Carolina.[7] It lived from 4.9 mya—300,000 years ago (4.6 million years ). It is distinguished from E. laurillardi by its slightly more gracile postcrania, and its complete 5 digits on the forelimb (manus), compared to 3 on E. laurillardi.[8]

E. laurillardi
E. laurillardi mounts in the Smithsonian

E. laurillardi, sometimes called the Panamerican ground sloth, was named by Lund (1842). It was previously considered a nomen dubium by Hoffstetter (1952), Gazin (1957) and Paula Couto (1979); it was recombined as Eremotherium laurillardi by Hoffstetter (1954), Cartelle and Bohorquez (1982), Cartelle and De Iuliis (1995) and Hulbert and Pratt (1998).[9][10] Fossil distribution was from the southern U.S. to Brazil. It lived from 780,000—11,000 years ago (0.769 million years ).

Fossil distribution

  • Fossilossa Site, Chatham County, Georgia. est. age ~2.0 Mya—400,000 years ago.
  • Isle of Hope, Chatham County, Georgia. est. age ~2.0 Mya.
  • Edisto Island, South Carolina est. age 400,000 years ago.
  • El Bosque, Nicaragua. est. age ~2.3—400,000 years ago.[11]
  • Masachapa, Nicaragua. est. age ~23.03 Mya.
  • La Coca, Panama. est. age ~500,000—400,000 years ago.
  • Zumbador Cave aka Cueva del Zumbador, Falcon, Venezuela. est. age ~1.8 Mya—11,000 years ago.
  • Cucuruchu, Venezuela. est. age ~125,000—11,000 years ago.
  • Rio Canas Site, Tablazo Formation, Manabí, Ecuador. est. age ~781,000—11,000 years ago.
  • Lagoa do Ipu Site, Ceara; Lage Grande-Level 1 & 2 Pernambuco, (Brazil. est. age ~1.8 Mya—11,000 years ago.
  • Toca da Janela da Barra do Antoniao and Lagoa Sao Vitor Piaui, Brazil. est. age ~126,000—11,000 years ago.
  • Toca da Esperanca, Bahia, Brazil. est. age ~126,000—11,000 years ago. est. age ~291,000 +/-84,000—204,000 years ago +/- 34,000.[12]

References
  1. PaleoBiology Database: Eremotherium, basic info
  2. Kürten, Björn (1980) Pleistocene mammals of North America p.140
  3. Tejada-Lara, Julia V. (2017-03-27). "Haile 7C". Florida Museum. Retrieved 2020-05-18.
  4. Oliveira, Jacqueline Freitas; Asevedo, Lidiane; Cherkinsky, Alexander; Dantas, M.A.T (October 2020). "Radiocarbon dating and integrative paleoecology (ẟ13C, stereomicrowear) of Eremotherium laurillardi (LUND, 1842) from midwest region of the Brazilian intertropical region". Journal of South American Earth Sciences. 102: 102653. doi:10.1016/j.jsames.2020.102653.
  5. Lindsey, Emily L.; Lopez Reyes, Erick X.; Matzke, Gordon E.; Rice, Karin A.; McDonald, H. Gregory (April 2020). "A monodominant late-Pleistocene megafauna locality from Santa Elena, Ecuador: Insight on the biology and behavior of giant ground sloths". Palaeogeography, Palaeoclimatology, Palaeoecology. 544: 109599. doi:10.1016/j.palaeo.2020.109599.
  6. Paleobiology Database: Panthera onca mesembrina, collections.
  7. Fields, Steven E., et al. "THE GROUND SLOTHS (PILOSA) OF SOUTH CAROLINA." PalArch's Journal of Vertebrate Palaeontology 9.3 (2012).
  8. Harrington, Arianna (2017-03-30). "Eremotherium eomigrans". Florida Museum. Retrieved 2020-05-18.
  9. Cartelle, Cástor; De Iuliis, Gerardo (1995). "Eremotherium laurillardi: The panamerican late Pleistocene megatheriid sloth". Journal of Vertebrate Paleontology. 15 (4): 830–841. doi:10.1080/02724634.1995.10011265.
  10. C. L. Gazin. 1957. Smithsonian Miscellaneous Collections 134
  11. W. D. Page. 1978. The geology of the El Bosque archaeological site, Nicaragua. Early Man in America from a Circum-pacific Perspective 231-260
  12. H. Lumley, M.-A. Lumley, M. C. Moraes Coutinho Beltrao, Y. Yokoyama, J. Labeyrie, J. Danon, G. Delibrias, C. Falgueres, and J. L. Bischoff. 1987. L'Anthropologie 91:917-942
  • Dinosaur Encyclopedia by Jayne Parsons
  • After the Dinosaurs: The Age of Mammals (Life of the Past) by Donald R. Prothero
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