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Eremotherium spp.
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Eremotherium spp.

[Image: 499px-WLA_hmns_Giant_ground_sloth_2.jpg]

Temporal range: Late Pliocene - Early Holocene, 4.9–0.011 Ma 

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)
Eremotherium is an extinct genus of ground sloth of the family Megatheriidae, endemic to North America and South 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.
E. rusconi reached a length up to 6 m (20 ft) and a weight of more than 3 tonnes.

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).

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.

[Image: 640px-Eremotherium_eomigrans_-_MUSE.JPG]
Claw of Eremotherium eomigrans at MUSE - Science Museum in Trento

Species
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. It lived from 4.9 mya—300,000 years ago (4.6 million years).
  • De Soto Shell Pit, DeSoto County, Florida. est. age ~1.6 Mya.
  • Payne Creek Mine, Polk County, Florida. est. age 1.6—1.5 Mya.
  • Crystal River Power Plant, Citrus County, Florida. est. age 1.6—1.5 Mya.
  • Inglis IA Site, Citrus County, Florida. est. age ~1.5 Mya.
  • Haile 7C Site, Alachua County, Florida. est. age ~1.6—1.5 Mya.
  • Haile 16A Site, Alachua County, Florida. ~1.6—1.5 Mya.
  • Cross Florida Barge Canal, Levy County, Florida. est. age ~1.6 Mya—400,000 years ago.
  • McLeod Limerock Mine, Levy County, Florida. est. age ~400,000 years ago.
  • Randall Parkway, New Hanover County, North Carolina. est. age ~400,000 years ago.
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). 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.
  • 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.


Ancient extinct sloth tooth in Belize tells story of creature's last year


February 27, 2019, University of Illinois at Urbana-Champaign

[Image: ancientextin.jpg]
Researchers analyzed the orthodentin and the cementum in the sloth tooth. Pits mark locations where samples were collected for analysis. Credit: Stanley Ambrose

Some 27,000 years ago in central Belize, a giant sloth was thirsty. The region was arid, not like today's steamy jungle. The Last Glacial Maximum had locked up much of Earth's moisture in polar ice caps and glaciers. Water tables in the area were low.

The sloth, a beast that stood up to 4 meters tall, eventually found water—in a deep sinkhole with steep walls down to the water. That is where it took its final drink. In 2014, divers found some of the sloth's remains—parts of a tooth, humerus and femur—while searching for ancient Maya artifacts in the pool, in Cara Blanca, Belize.

Though partially fossilized, the tooth still held enough unaltered tissue for stable carbon and oxygen isotope analysis, which provided clues to what the sloth ate in the last year of its life. This, in turn, revealed much about the local climate and environment of the region at the time. The findings, reported in the journal Science Advances, will aid the study of similar fossils in the future, the researchers said.

"We began our study with the hopes of gaining a better understanding of the landscape within which large mammals went extinct and humans emerged in central Belize," said University of Illinois graduate student Jean T. Larmon, who led the research with U. of I. anthropology professors Lisa Lucero and Stanley Ambrose. "In the process, we discovered which part of the tooth had best maintained its integrity for analysis. And we refined methods for studying similar specimens in the future."

The new findings "add to the evidence that many factors, in addition to a changing climate, contributed to the extinction of megafauna in the Americas," said Lucero, who studies the ancient Maya of central Belize. "One of those potential factors is the arrival of humans on the scene 12,000 to 13,000 years ago."

The teeth of giant sloths like the one found in Belize, Eremotherium laurillardi, differ from those of other large mammals, like mammoths, that went extinct between 14,000 and 10,000 years ago, Larmon said.

"Giant sloth teeth have no enamel, the hard, outer layer of human and some animal teeth that can be analyzed to learn about their diet," she said.

[Image: 1-ancientextin.jpg]
The ancient sloth, Eremotherium laurillardi, grew up to 4 meters in height. Credit: Julie McMahon

Other factors have limited scientists' ability to study the teeth of ancient sloths. Most are fossilized, with minerals replacing much or all of the original tissue and bone.

By using cathodoluminescence microscopy, a technique that causes minerals to glow and can detect the extent of mineralization in fossils, the researchers discovered that one type of tooth tissue, the dense orthodentin, was largely intact.

Larmon drilled 20 samples of orthodentin for isotopic analysis along the 10-centimeter-long tooth fragment, spanning more than a year of tooth growth.

"This allowed us to trace monthly and seasonal changes in the sloth's diet and climate for the first time, and also to select the best part of the tooth for reliable radiocarbon dating," Ambrose said.

[Image: thetoothofth.jpg]
Part of an extinct giant sloth's upper humerus recovered by divers during the 2014 excavations. Credit: Lisa J. Lucero, VOPA

The isotopic analysis revealed that the giant sloth lived through a long dry season, which lasted about seven months, sandwiched between two short rainy seasons. The analysis also revealed that the creature lived in a savanna, rather than a forest, and consumed a variety of plants that differed between wet and dry seasons.

"We were able to see that this huge, social creature was able to adapt rather readily to the dry climate, shifting its subsistence to relying upon what was more available or palatable," Larmon said.

"This supports the idea that the sloths had a diverse diet," Lucero said. "That helps explain why they were so widespread and why they lasted so long. It's likely because they were highly adaptable."

https://phys.org/news/2019-02-ancient-ex...elize.html


Journal Reference:
J.T. Larmon el al., "A year in the life of a giant ground sloth during the Last Glacial Maximum in Belize," Science Advances (2019). DOI: 10.1126/sciadv.aau1200 ,

Abstract
Stable isotope analysis of the first fossilized Eremotherium laurillardi remains from Belize offers valuable insights into the conditions within which this individual lived and its ability to adapt to the increasing aridity of the Last Glacial Maximum (LGM). Cathodoluminescence (CL) microscopy was used to identify chemical alteration of the tooth during fossilization. Results demonstrate that the inner orthodentin resists diagenesis, yielding potentially unaltered values. Using an intensive “vacuum milling” technique, the inner orthodentin produced an accelerator mass spectrometry (AMS) date of 26,975 ± 120 calibrated years before the present. The stable carbon and oxygen isotope analysis of this layer shows that the tooth recorded two wet seasons separated by one longer dry season and that this sloth was able to adapt its diet to the marked seasonality of the LGM. This study offers new insights into obtaining reliable isotope data from fossilized remains and suggests that this individual adapted to climate shifts, contributing to the conversation surrounding megafauna extinction.

http://advances.sciencemag.org/content/5/2/eaau1200
[Image: wildcat10-CougarHuntingDeer.jpg]
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