New insights on the paleogeographic distribution of the Late Pleistocene ground sloth genus Xibalbaonyx along the Mesoamerican Corridor

The inhibitory cascade (IC) represents a developmental model that explains the evolution of molar relative sizes, originally described in rodents but later validated in several mammalian groups. The IC comprises signalling molecules produced by the first molar buds that inhibit the development of subsequent molars and molecules from surrounding tissues that have opposite effects. Sloths, as xenarthrans, present many peculiarities in their dentition, like tooth and enamel loss, homodonty, and changes in the typically mammalian dental formula. Here, we test the existence of an IC and explore the evolution of the lower dentition in sloths. We studied the variability of molariform proportions in 20 specimens of the Late Pleistocene ground sloth Lestodon armatus. We also analysed molariforms proportions in 53 sloth genera to explore evolutionary trends. Our results show that the lower dentition of most sloths complies with the IC model, despite the difficulties of assessing dental homologies with other mammals. Furthermore, we tested the existence of different patterns among families, obtaining support for models taking mylodontids and orophodontids separately from the rest of sloths. Also, members of Mylodontidae show a unique IC pattern, with a slope considerably higher than 2 and an mf1 ≤ mf2 << mf3 configuration. This pattern could be related to the morphological adaptations to grazing showed by mylodontids during most of their evolutionary history.

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A new genus of megalonychid ground sloth (Mammalia, Xenarthra) from the late Pleistocene of Quintana Roo, Mexico

Journal of Vertebrate Paleontology ◽

10.1080/02724634.2017.1307206 ◽

2017 ◽

Vol 37 (3) ◽

pp. e1307206 ◽

Cited By ~ 12

Author(s):

H. Gregory McDonald ◽

James C. Chatters ◽

Timothy J. Gaudin

Keyword(s):

Late Pleistocene ◽

New Genus ◽

Quintana Roo ◽

Ground Sloth

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A new record of Paramylodon harlani (Owen 1840) (Xenarthra, Pilosa, Mylodontidae) from the late Pleistocene of Valsequillo, Puebla, with comments on its paleobiogeography and paleoecology in Mexico

Boletín de la Sociedad Geológica Mexicana ◽

10.18268/bsgm2021v73n1a100720 ◽

2021 ◽

Vol 73 (1) ◽

pp. A100720

Author(s):

Gerardo Carbot-Chanona ◽

Eduardo Jiménez-Hidalgo ◽

Francisco J. Jiménez-Moreno ◽

Enrique Benítez-Gálvez

Keyword(s):

Late Pleistocene ◽

New Record ◽

Volcanic Belt ◽

The United States ◽

Southeastern Part ◽

Left Tibia ◽

The North ◽

Preferred Habitat ◽

Mexican Volcanic Belt ◽

Ground Sloth

Paramylodon harlani was a large ground sloth recorded across North America, from Canada to Mexico. In Mexico, it is known from several late Pleistocene localities, but most of these records just mention the taxon in passing and few specimens have been described or illustrated. In this work, we describe a left tibia from the Valsequillo Basin, Puebla state. Its morphology and measurements allowed us to identify it as Paramylodon harlani, adding a new record for Mexico. In Mexico, P. harlani occurred mainly in the Trans-Mexican Volcanic Belt, central Mexico, with some records in the north and southeastern part of the country. Most localities are located between 1500 to 2000 m.a.s.l. Paleoenvironmental and paleoclimatic inference in some localities of Mexico where P. harlani occurred, showed heterogenous vegetation dominated by grasslands, and agree with the preferred habitat proposed for this species based on localities in the United States. This indicates that P. harlani could inhabit different environments, from grasslands to more wooded areas, and this adaptation allowed it to extend its range from the north to the southeast of Mexico.

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Xibalbaonyx oviceps, a new megalonychid ground sloth (Folivora, Xenarthra) from the Late Pleistocene of the Yucatán Peninsula, Mexico, and its paleobiogeographic significance

PalZ ◽

10.1007/s12542-017-0349-5 ◽

2017 ◽

Vol 91 (2) ◽

pp. 245-271 ◽

Cited By ~ 13

Author(s):

Sarah R. Stinnesbeck ◽

Eberhard Frey ◽

Jerónimo Avíles Olguín ◽

Wolfgang Stinnesbeck ◽

Patrick Zell ◽

...

Keyword(s):

Late Pleistocene ◽

Yucatan Peninsula ◽

Yucatán Peninsula ◽

Ground Sloth

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3D model related to the publication: Presence of the ground sloth Valgipes bucklandi (Xenarthra, Folivora, Scelidotheriinae) in southern Uruguay during the Late Pleistocene: Ecological and biogeographical implications

MorphoMuseuM ◽

10.18563/journal.m3.147 ◽

2021 ◽

Vol 7 (2) ◽

pp. e147

Author(s):

Luciano Varela ◽

Carolina Lobato ◽

P. Sebastián Tambusso

Keyword(s):

Late Pleistocene ◽

3D Model ◽

Ground Sloth

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New species of the ground sloth Parocnus from the late Pleistocene-early Holocene of Hispaniola

Vertebrate Anatomy Morphology Palaeontology ◽

10.18435/vamp29369 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Robert McAfee ◽

Sophia Beery ◽

Renato Rimoli ◽

Juan Almonte ◽

Phillip Lehman ◽

...

Keyword(s):

New Species ◽

Dominican Republic ◽

Late Pleistocene ◽

Early Holocene ◽

Size Dimorphism ◽

The Holocene ◽

Ground Sloth ◽

A New Species ◽

Partial Skeleton

Parocnus dominicanus sp. nov. represents a new species of megalonychid ground sloth from theAltagracia Province of southeastern Dominican Republic. Specimens of multiple individuals, including oneassociated partial skeleton, were recovered from two separate underwater caves in the Parque Nacional delEste through collaborations with museums and cave divers between 2009–2013. Parocnus dominicanus sp.nov. is distinguished by its small size compared to that of P. serus, with percent differences in limb elementlengths ranging from 13−24%. Numerous cranial and post-cranial elements also exhibit morphological characterstates that are not attributable to size variations. The recovery of multiple individuals within each localitydemonstrates a size dimorphism, possibly sexual, which parallels patterns exhibited by P. serus. The twospecies are also geographically distinct, with no examples of co-occurrence at any localities to date. Parocnusdominicanus sp. nov. and P. serus share character states that are distinct from those of the Cuban species, P.browni, and which suggest differential usage of the forelimb. The exact age of the specimens described here isunknown, however, Parocnus has been dated to the Holocene in Haiti.http://zoobank.org/urn:lsid:zoobank.org:pub:12E495D3-E261-4522-9854-D3B4C2D5FFB8

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Late Pleistocene Extinction and Radiocarbon Dating

American Antiquity ◽

10.2307/277160 ◽

1960 ◽

Vol 26 (1) ◽

pp. 58-77 ◽

Cited By ~ 22

Author(s):

Jim J. Hester

Keyword(s):

Great Basin ◽

Late Pleistocene ◽

Great Plains ◽

Bison Bison ◽

Radiocarbon Dates ◽

Alphabetical Listing ◽

Pleistocene Mammals ◽

Ground Sloth ◽

Dire Wolf ◽

Late Survival

AbstractAll radiocarbon dates from North America, associated with extinct Late Pleistocene mammals, those from levels stratigraphically later than levels with extinct forms, and dates associated with recent fauna are tabulated alphabetically by site. Dates associated with extinct fauna are cross-referenced in an alphabetical listing of species. Dates considered invalid are tabulated and are not utilized in formulating conclusions. Most herding animals, such as the Columbian mammoth, horse, camel, and bison, as well as the dire wolf, rapidly became extinct about 8000 years ago. The dates suggest a southward withdrawal from the Great Plains by the mammoth and a partial contemporaneity of Clovis elephant hunters in southern Arizona with Folsom bison hunters on the Plains. Dates for the extinction of the Imperial mammoth are probably too early. The mastodon may have survived in isolated areas after the extinction of other forms. The super bison may have become extinct earlier than 8000 years ago and Bison bison seems to have been present in some areas before the extinction of B. antiquus. Radiocarbon dates do not support the supposed late survival of the ground sloth. Extinction apparently occurred earlier in the Great Basin and Coahuila than in intervening areas.

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LATE PLEISTOCENE SHASTA GROUND SLOTH (XENARTHRA) DUNG, DIET, AND ENVIRONMENT FROM THE SIERRA VIEJA, PRESIDIO COUNTY, TEXAS

Texas Journal of Science ◽

10.32011/txjsci_73_1_article3 ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Jim I. Mead ◽

Bryon A. Schroeder ◽

Chad L. Yost

Keyword(s):

Late Pleistocene ◽

Local Community ◽

Late Glacial ◽

C4 Grasses ◽

Macrobotanical Remains ◽

New Information ◽

Juniper Woodland ◽

C3 And C4 Grasses ◽

Ground Sloth ◽

Glacial Time

Abstract We present new information about the Late Pleistocene Shasta ground sloth (Nothrotheriops shastensis). Spirit Eye Cave in the Sierra Vieja along the Rio Grande provides the newest evidence that the Shasta ground sloth inhabited further south in the mountains of the southwestern Trans-Pecos, Texas, than has been previously documented. The cave is one of only twelve known Nothrotheriops dung localities. During excavation of the cave, packrat middens and sloth dung were discovered. Two areas within the cave provide radiocarbon dated ground sloth dung and packrat midden macrobotanical remains which permit the reconstruction of the sloth diet and local biotic habitat at 30,800 and 12,900 calibrated YBP. The local community at 30,800 calibrated years ago was a pinyon-juniper woodland with yucca, sandpaper bush, globemallow, cactus, and barberry in the understory based on the packrat midden from the cave. The dung contents indicate that the diet of the sloth included C3 and C4 grasses along with Agave. Data for the local vegetation community and sloth diet from 12,900 years ago indicate that during this late glacial time, the region was still a pinyon-juniper woodland but also contained Celtis, Quercus, and Larrea, among other taxa.

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