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

  title={Xibalbaonyx oviceps, a new megalonychid ground sloth (Folivora, Xenarthra) from the Late Pleistocene of the Yucat{\'a}n Peninsula, Mexico, and its paleobiogeographic significance},
  author={Sarah R. Stinnesbeck and Eberhard Frey and Jer{\'o}nimo Av{\'i}les Olgu{\'i}n and Wolfgang Stinnesbeck and Patrick Zell and Heinrich Mallison and Arturo Gonz{\'a}lez Gonz{\'a}lez and Eugenio Aceves N{\'u}{\~n}ez and Adriana Vel{\'a}zquez Morlet and Alejandro Terrazas Mata and Martha Benavente Sanvicente and F{\'a}bio Adriano Hering and Carmen Rojas Sandoval},
Here we describe a new genus and species of giant ground sloth, Xibalbaonyx oviceps (Megalonychidae, Xenarthra), from the drowned cave system of the northeastern Yucatán Peninsula. The specimen is Late Pleistocene in age and was discovered in the Zapote sinkhole (cenote) near Puerto Morelos in the Mexican state of Quintana Roo. Xibalbaonyx oviceps differs significantly from all hitherto known Megalonychidae including those from the Greater Antilles and South America. The new taxon suggests a… 

Xibalbaonyx exinferis n. sp. (Megalonychidae), a new Pleistocene ground sloth from the Yucatán Peninsula, Mexico

ABSTRACT Recent palaeontological research in submerged caves of the north-eastern Yucatán Peninsula (YP) in Mexico has resulted in the identification of a diverse megafaunal assemblage in the area,

Life and death of the ground sloth Xibalbaonyx oviceps from the Yucatán Peninsula, Mexico

ABSTRACT Ongoing investigations in submerged cave systems of Quintana Roo in south-eastern Mexico reveal a rich Late Pleistocene megafaunal assemblage, among them the megalonychid ground sloth

Panthera balamoides and other Pleistocene felids from the submerged caves of Tulum, Quintana Roo, Mexico

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First record of Meizonyx salvadorensis (Mammalia: Xenarthra: Pilosa) from the late Pleistocene of Mexico and its evolutionary implications

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Megalonychid Sloths from the Early Late Hemphillian (Late Miocene), Curré Formation, San Gerardo de Limoncito, Costa Rica

A reevaluation of the late Miocene megalonychid fossils found at San Gerardo de Limoncito, Coto Brus Valley, Costa Rica is presented, and material is considered to be a new species of Zacatzontli based on a comparison with the type and other members of the Megalonychidae from the Hemphillian of North America.

Muknalia minima from the Yucatán of Mexico is synonymous with the collared peccary, Pecari tajacu (Artiodactyla: Tayassuidae)

Measurements and intact morphological features indicate the Muknal Cave specimen belongs to the extant collared peccary, Pecari tajacu, and diagnostic characters of this taxon include a concave notch along the caudal edge of the ascending ramus and a ventrally directed angular process.

Yukon to the Yucatan: Habitat partitioning in North American Late Pleistocene ground sloths (Xenarthra, Pilosa)

The late Pleistocene mammalian fauna of North America included seven genera of ground sloth, representing four families. This cohort of megaherbivores had an extensive geographic range in North



A New Genus of Megalonychid Sloth (Mammalia, Xenarthra) from the Late Pleistocene (Lujanian) of Sierra De Perija, Zulia State, Venezuela

A cladistic analysis of the new taxon based on cranial characters indicates that it is closely related to Ahytherium, another late Pleistocene megalonychid from South America known from cranial remains, and suggests that there may have been at least two distinct clades within the family since the late Miocene.

New Megalonychid Sloths (Phyllophaga, Xenarthra) from the Quaternary of Hispaniola

It is inferred that the later subdivision and subsidence of major portions of GAARlandia must have finely vicariated its biota (which included sloths at least as early as the Early Oligocene), consistent with several new lines of evidence concerning the paleontological and paleogeographical history of the Caribbean region.

New Pleistocene remains of megalonychid ground sloths (Xenarthra: Pilosa) from the intertropical Brazilian region

Comparisons of the mandible and ossicles are conducted with homologous elements of the contemporaneous and sympatric Ahytherium aureum Cartelle, De Iuliis, and Pujos, 2008, and reinforce the distinction between these two species detailed in their initial descriptions.

A peculiar climbing Megalonychidae from the Pleistocene of Peru and its implication for sloth history

The discovery of D. nordenskioldi underscores the great adaptability of Tardigrada: an arboreally adapted form is now added to the already known terrestrial, subarboreal, and aquatic (marine and freshwater) fossil sloths.


A megalonychid mandibular portion coming from Mio-Pliocene deposits of Entre Rios Province is described and is relatecl to many other extinct forms (Ottotherium), and from an environmental point of view, this new Tardigrada is indicative of a warm ancl humid forest.

The oldest Megalonychidae (Xenarthra:Tardigrada); phylogenetic relationships and an emended diagnosis of the family

A new genus and species of Megalonychidae, Deseadognathus riggsi, is described from the type locality of the Deseadan Land-Mammal Age, Oligocene of Patagonia, Argentina, the oldest megalonychid thus far known and the results of the phylogenetic analysis confirm the monophyletic status of the Megaloneychidae with an enlarged membership.

Eucholoeops Ameghino, 1887 (Xenarthra, Tardigrada, Megalonychidae) from the Santa Cruz Formation, Argentine Patagonia: implications for the systematics of Santacrucian sloths

ABSTRACT New well-preserved remains of the megalonychid sloth Eucholoeops Ameghino, 1887 recovered under strict stratigraphic control from late Early Miocene Santa Cruz Formation (c. 19 to 14 Ma;