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

Iuliis, Gerardo De; Pujos, François; Toledo, Néstor; Bargo, M. Susana; Vizcaı́no, Sergio F.

doi:10.5252/g2014n2a2

Cited by 503 publications

(19 citation statements)

References 58 publications

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“…E, F), but smaller than that in Huilabradys magdaleniensis and in Megalonychidae (e.g. Eucholoeops ingens , De Iuliis et al ., ), and than that in some Mylodontidae that possess a robust caniniform.…”

Section: Description Of Aymaratheriummentioning

confidence: 84%

“…The dentition of Aymaratherium jeani includes a caniniform followed by three molariform teeth, which is characteristic of basal tardigrade taxa such as Pseudoglyptodon and Octodontotherium (Tinguirirican and Deseadan SALMAs: Engelmann, ; McKenna, Wyss & Flynn, ; Pujos & De Iuliis, ; Pujos et al ., ), as well as the nothrotherids Nothropus , Mionothropus and Pronothrotherium , and several other Miocene basal megatherioid sloths (Santacrucian SALMA: e.g. Scott, , ; De Iuliis et al ., ).…”

Section: Description Of Aymaratheriummentioning

confidence: 97%

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A new nothrotheriid xenarthran from the early Pliocene of Pomata-Ayte (Bolivia): new insights into the caniniform-molariform transition in sloths

et al. 2016

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Tardigrade xenarthrans are today represented only by the two tree sloth genera Bradypus and Choloepus, which inhabit the Neotropical rainforests and are characterized by their slowness and suspensory locomotion. Sloths have been recognized in South America since the early Oligocene. This monophyletic group is represented by five clades traditionally recognized as families: Bradypodidae, Megalonychidae, Mylodontidae ( †), Megatheriidae ( †) and Nothrotheriidae ( †). A new nothrotheriid ground sloth represented by a dentary and several postcranial elements, Aymaratherium jeani gen. nov., sp. nov., from the early Pliocene locality of Pomata-Ayte (Bolivia) is reported. This small-to medium-sized species is characterized especially by its dentition and several postcranial features. It exhibits several convergences with the 'aquatic' nothrotheriid sloth Thalassocnus and the giant megatheriid ground sloth Megatherium (M.) americanum, and is interpreted as a selective feeder, with good pronation and supination movements. The tricuspid caniniform teeth of Aymaratherium may represent a transitional stage between the caniniform anterior teeth of basal megatherioids and basal nothrotheriids (1/1C-4/3M as in Hapalops or Mionothropus) and the molariform anterior teeth of megatheriids (5/4M, e.g. Megatherium). To highlight the phylogenetic position of this new taxon among nothrotheriid sloths, we performed a cladistic assessment of the available dental and postcranial evidence. Our results, derived from a TNT treatment of a data matrix largely based on a published phylogenetic data set, indicate that Aymaratherium is either sister taxon to Mionothropus or sister to the clade Nothrotheriini within Nothrotheriinae. They further support the monophyly of both the Nothrotheriinae and the Nothrotheriini, as suggested previously by several authors.

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Section: Description Of Aymaratheriummentioning

confidence: 84%

Section: Description Of Aymaratheriummentioning

confidence: 97%

A new nothrotheriid xenarthran from the early Pliocene of Pomata-Ayte (Bolivia): new insights into the caniniform-molariform transition in sloths

et al. 2016

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“…A, B), but wraps tightly around this tooth, similar to the morphology in the basal megalonychid Eucholoeops ingens Ameghino, (see De Iuliis et al . ). This morphology is apparent in ventral view (Fig.…”

Section: Discussionmentioning

confidence: 97%

The mylodontine ground slothGlossotherium tropicorumfrom the late Pleistocene of Ecuador and Peru

Iuliis

Cartelle

McDonald

et al. 2017

Papers in Palaeontology

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New mylodontine (Xenarthra, Pilosa) sloth remains from the late Pleistocene tar seep localities of Corralito (Ecuador) and Talara (Peru) are described, and the taxonomic history of the extinct ground sloth genus Glossotherium is reviewed. Based on the new material and comparisons with Glossotherium robustum, Glossotherium wegneri, and the North American taxon, Paramylodon harlani, the species Glossotherium tropicorum is considered to be valid and a new definition of its diagnostic characters is provided. Glossotherium tropicorum is similar in size to Glossotherium robustum and Glossotherium wegneri but differs in several respects from these species, such as having a more elongated and slender skull. In this respect it more closely resembles Paramylodon harlani in North America, which is also similar in size. Glossotherium tropicorum is one of two mylodontine sloths found in the upper Pleistocene of north‐western South America, the other being Glossotherium wegneri. While both are present in this region their individual distributions did not overlap and the two species have not been recovered together in a fauna. The distribution of Glossotherium tropicorum is restricted to lowland coastal areas whereas Glossotherium wegneri is found inland and in the highland areas of the Andes, suggesting significant differences in their ecology.

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“…However, in all of these, the anteriormost portion is wider transversely and is ovate in shape, with the foramen tapering posteromedially. An ovate incisive foramen is also present in the basal megatherioid Hapalops elongatus (Scott 1903-4;De Iuliis 1994) and Eucholoeops fronto (Scott 1903-4), though it is more triangular in H. longiceps (Scott 1903-4;De Iuliis 1994) and E. ingens (Bargo et al 2009;De Iuliis et al 2014). The margin of the foramen is formed mostly by the medial and lateral rami of the premaxilla, but the maxilla also participates in the posterolateral margin in all of the Choloepus specimens examined in the present study.…”

Section: And 5)mentioning

confidence: 96%

Premaxillae of the Extinct Megalonychid Sloths Acratocnus, Neocnus, and Megalonyx, and their Phylogenetic Implications (Mammalia, Xenarthra)

Lyon

Powell

McDonald³

et al. 2015

J Mammal Evol

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In most folivorans, the premaxilla is loosely attached to the maxilla, so that it is often missing in otherwise very well-preserved fossil skulls. Despite its infrequent preservation in sloths, the premaxilla has been shown to have phylogenetically significant variation among the taxa that do preserve the element. In the family Megalonychidae, the premaxilla is known only in the early taxon Eucholoeops (Santacrucian South American Land Mammal Age [SALMA]), the extant two-toed sloth Choloepus, and the North American Neogene taxon Megalonyx, the last described only in an unpublished Master's thesis. We report here the discovery of the premaxilla in two genera of extinct megalonychids, Neocnus and Acratocnus. These small bodied, semiarboreal megalonychid sloths are endemic to the islands of the Greater Antilles. Though the presence of sloths in the Caribbean dates at least to the late Oligocene, the best known taxa derive from Pleistocene to Holocene cave deposits in Puerto Rico, Hispaniola, and Cuba. We also describe the premaxilla in two species of Megalonyx from North America, the Blancan North American Land Mammal Age (NALMA) M. leptostomus and Rancholabrean NALMA M. jeffersonii. These species show a progressive reorientation of the premaxilla within Megalonyx from a primitive horizontal element to a nearly vertical element, and some significant changes in the anatomy of the incisive foramen. Morphological evidence suggests that a broadened, plate-like premaxilla constitutes a synapomorphy for the entire clade Megalonychidae. Furthermore, although Eucholoeops retains a short anterior process of the premaxilla like that of megatherioid sloths, this process is lacking in the other megalonychids, suggesting that the loss of this process may unite late Miocene to Recent megalonychids.

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

Cited by 503 publications

References 58 publications

A new nothrotheriid xenarthran from the early Pliocene of Pomata-Ayte (Bolivia): new insights into the caniniform-molariform transition in sloths

A new nothrotheriid xenarthran from the early Pliocene of Pomata-Ayte (Bolivia): new insights into the caniniform-molariform transition in sloths

The mylodontine ground slothGlossotherium tropicorumfrom the late Pleistocene of Ecuador and Peru

Premaxillae of the Extinct Megalonychid Sloths Acratocnus, Neocnus, and Megalonyx, and their Phylogenetic Implications (Mammalia, Xenarthra)

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