Megatheriinae

Last updated

Megatheriinae
Megatherium americanum Skeleton NHM.JPG
Megatherium americanum skeleton, Natural History Museum, London
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Pilosa
Family: Megatheriidae
Subfamily: Megatheriinae
Gill, 1872
Genera

Megatheriinae is a subfamily of the Megatheriidae, an extinct family of ground sloths that lived from the Middle Miocene to the Early Holocene. [2] [3]

Classification

Within the Megatheriidae there are two (possibly three) subfamilies; the Megatheriinae and the Planopsinae. The phylogenetically older group is represented by the Planopsinae from the Lower and Middle Miocene. These still possessed a caniniform anterior tooth, which was separated from the posterior molar-like teeth by a small diastema . The more derived Megatheriinae, which are known from the Middle Miocene to the Early Holocene, on the other hand, had fully homodontic molars in a closed row. [4] Originally, the subfamilies of the Nothrotheriinae and the Schismotheriinae were also placed in the Megatheriidae. [5] Based on skull studies, the Nothrotheriidae, in which, among other genera, Nothrotherium , Nothrotheriops, and the semiaquatic Thalassocnus are placed, are regarded as a separate family, which forms the sister group of the Megatheriidae. [6]

Megatheriidae  
  Planopsinae  

  Prepoplanops

  Planops

  Prepotherium

 Megatheriinae 

  Diabolotherium

  Megathericulus

  Anisodontherium

  Pyramiodontherium

  Proeremotherium

  Eremotherium

  Megatherium

Related Research Articles

<span class="mw-page-title-main">Mylodontidae</span> Extinct family of ground sloths

Mylodontidae is a family of extinct South American and North American ground sloths within the suborder Folivora of order Pilosa, living from around 23 million years ago (Mya) to 11,000 years ago. This family is most closely related to another family of extinct ground sloths, Scelidotheriidae, as well as to the extant arboreal two-toed sloths, family Choloepodidae; together these make up the superfamily Mylodontoidea. Phylogenetic analyses based on morphology uncovered the relationship between Mylodontidae and Scelidotheriidae; in fact, the latter was for a time considered a subfamily of mylodontids. However, molecular sequence comparisons were needed for the correct placement of Choloepodidae. These studies have been carried out using mitochondrial DNA sequences as well as with collagen amino acid sequences. The latter results indicate that Choloepodidae is closer to Mylodontidae than Scelidotheriidae is. The only other living sloth family, Bradypodidae, belongs to a different sloth radiation, Megatherioidea.

<i>Thalassocnus</i> Extinct, aquatic ground sloth from South America

Thalassocnus is an extinct genus of semiaquatic ground sloths from the Miocene and Pliocene of the Pacific South American coast. It is monotypic within the subfamily Thalassocninae. The five species—T. antiquus, T. natans, T. littoralis, T. carolomartini, and T. yuacensis—represent a chronospecies, a population gradually adapting to marine life in one direct lineage. They are the only known aquatic sloths, but they may have also been adapted to a terrestrial lifestyle. They have been found in the Pisco Formation of Peru, the Tafna Formation of Argentina, and the Bahía Inglesa, Coquimbo, and Horcón formations of Chile. Thalassocninae has been placed in both the families Megatheriidae and Nothrotheriidae.

<i>Eremotherium</i> Extinct genus of giant ground sloth

Eremotherium is an extinct genus of giant ground sloth in the family Megatheriidae. Eremotherium lived in southern North America, Central America, and northern South America from the Pliocene, around 5.3 million years ago, to the end of the Late Pleistocene, around 10,000 years ago. Eremotherium was widespread in tropical and subtropical lowlands and lived there in partly open and closed landscapes, while its close relative Megatherium lived in more temperate climes of South America. Both genera reached the size of today's elephants and were among the largest mammals in the Americas. Characteristic of Eremotherium was its robust physique with comparatively long limbs and front and hind feet especially for later representatives- three fingers. However, the skull is relatively gracile, the teeth are uniform and high-crowned. Like today's sloths, Eremotherium was purely herbivorous and was probably a mixed feeder that dined on leaves and grasses. Eremotherium was a generalist that could adapt its diet to the respective local and climatic conditions of many regions. Finds of Eremotherium are common and widespread, with fossils being found as far north as South Carolina in the United States and as far south as Rio Grande Do Sul in Brazil, and many complete skeletons have been unearthed.

<span class="mw-page-title-main">Mylodontinae</span> Extinct subfamily of mammals

Mylodontinae is an extinct subfamily of ground sloths that lived from the Early Miocene to the Early Holocene epochs.

Ahytherium is an extinct genus of megalonychid sloth that lived during the Pleistocene of what is now Brazil. It contains a single species, A. aureum.

<span class="mw-page-title-main">Nothrotheriidae</span> Extinct family of ground sloths

Nothrotheriidae is a family of extinct ground sloths that lived from approximately 17.5 mya—10,000 years ago, existing for approximately 17.49 million years. Previously placed within the tribe Nothrotheriini or subfamily Nothrotheriinae within Megatheriidae, they are now usually placed in their own family, Nothrotheriidae. Nothrotheriids appeared in the Burdigalian, some 19.8 million years ago, in South America. The group includes the comparatively slightly built Nothrotheriops, which reached a length of about 2.75 metres (9.0 ft). While nothrotheriids were small compared to some of their megatheriid relatives, their claws provided an effective defense against predators, like those of larger anteaters today.

The Curré Formation is a geologic formation of the Taraba Basin Group in Costa Rica. The deltaic conglomerates preserve fossils dating back to the Late Miocene to Early Pliocene period (Hemphillian).

<i>Pseudoprepotherium</i> Extinct genus of ground sloths

Pseudoprepotherium is an extinct genus of sloths of the family Mylodontidae. It was widespread across northern South America during the Early to Late Miocene epoch around 21 to 5.3 million years ago. Fossils of the animal have been found in Brazil, Venezuela, and Peru. Pseudoprepotherium lived in a tropical climate with a water-rich environment. Their known remains are limited to limb bones, except for a few skulls and teeth. Based on these remains, they were most likely medium to large-sized mylodontid. The genus was described in 1961 and currently contains three species, which were originally assigned to the genus Prepotherium.

Megathericulus is an extinct genus of ground sloths in the Megatheriidae family. It lived during the Middle Miocene, 11-16 Ma in what is now South America. Fossils have been found principally in Argentina, Bolivia, and Peru. It is a smaller representative of the megatheres. Despite being one of the earliest-known members of the family, its dentition structure is associated with homodont teeth belonging to the more modern line of evolution. The genus was scientifically named in 1904. Only one species is currently recognized, Megathericulus patagonicus.

Sibotherium is an extinct genus of ground sloth in the family Megatheriidae that lived in what is now Costa Rica during the Late Miocene. It was a large ground sloth, weighing more than 2,500 kg.

<i>Proeremotherium</i> Extinct genus of mammals

Proeremotherium is an extinct genus of megatheriine ground sloths in the family Megatheriidae. It lived during the Late Miocene and Early Pliocene of what is now Venezuela. So far, two largely complete skulls have been recovered in the Falcón Basin in Venezuela. The finds identify the animals as medium-sized representatives of the Megatheriidae. In the cranial anatomy, Proeremotherium resembles the later and giant Eremotherium. It is therefore assumed that the two ground sloths are directly related to each other.

Urumacotherium is an extinct genus of ground sloths of the family Mylodontidae. It lived from the Middle Miocene to the Early Pliocene of what is now Brazil, Peru and Venezuela.

Simomylodon is an extinct genus of ground sloths from the family Mylodontidae. It lived from the Late Miocene to the Middle Pliocene of what is now Bolivia and Argentina, 5.3 to 2.8 million years ago. The most important find material comes from the central Altiplano in Bolivia and includes several skulls and dentition remains. Thus, the so far documented body skeleton is the best known and most significant of a Miocene representative of the Mylodontidae. On the basis of the remains, it can be concluded that it is a rather small member of the Mylodontidae. The construction of the limbs supports ground-dwelling locomotion, but this does not exclude occasional digging or climbing. The type and only known species is Simomylodon uccasamamensis.

Lakukullus is an extinct genus of nothrotheriid ground sloths that lived during the Middle Miocene around 13.8 to 11.8 million years ago of what is now Bolivia.

<i>Prepoplanops</i> Extinct genus of ground sloths

Prepoplanops is an extinct genus of ground sloth of the family Megatheriidae. It lived in the Miocene around 18 to 16 million years ago of what is now Argentina. The only known species is Prepoplanops boleadorensis.

Aymaratherium is an extinct genus of nothrotheriid ground sloths that lived during the Late Miocene and Early Pliocene of Bolivia. Fossils of Aymaratherium have been found in the Pomata Ayte locality of the Umala Formation.

Urumacocnus is an extinct genus of megalonychid sloth that lived during the Miocene in Venezuela. The genus contains one known species, Urumacocnus urbanii. Fossils have been found in the Urumaco Formation of Venezuela.

Mesopotamocnus is an extinct genus of megalonychid ground sloth that lived during the Late Miocene in what is now Argentina. Fossils have been found in the Ituzaingó Formation of Argentina.

Bolivartherium is an extinct genus of mylodontine mylodontid sloth that lived during the Late Miocene and Late Pliocene in what is now Venezuela. Fossils have been found in the Codore and Urumaco Formations of Venezuela.

<i>Magdalenabradys</i> Extinct genus of ground sloths

Magdalenabradys is an extinct genus of mylodontid ground sloths that lived during the Middle Miocene and Early Pliocene of what is now Colombia and Venezuela. Fossils have been found in the Villavieja Formation of the Honda Group in Colombia, and the Codore and Urumaco Formations of Venezuela.

References

  1. Rincón, Ascanio D.; Valerio, Ana L.; Laurito, César A.; Rincón, Ascanio D.; Valerio, Ana L.; Laurito, César A. (June 2020). "First fossil record of a Megatheriidae-Megatheriinae in the Early Hemphillian (Late Miocene) from San Gerardo de Limoncito, Curré Formation, Costa Rica". Revista Geológica de América Central (62): 1–24. doi:10.15517/rgac.v62i0.41278 (inactive 31 January 2024). ISSN   0256-7024.{{cite journal}}: CS1 maint: DOI inactive as of January 2024 (link)
  2. Luliis, Gerardo De (1996). A systematic review of the Megatheriinae (Mammalia: Xenarthra Megatheriidae) (Thesis).
  3. Varela, Luciano; Tambusso, P Sebastián; McDonald, H Gregory; Fariña, Richard A (2018-09-15). "Phylogeny, Macroevolutionary Trends and Historical Biogeography of Sloths: Insights From a Bayesian Morphological Clock Analysis". Systematic Biology. 68 (2): 204–218. doi:10.1093/sysbio/syy058. ISSN   1063-5157. PMID   30239971.
  4. Carlini, Alfredo A.; Brandoni, Diego; Dal Molin, Carlos N. (2013). "A new genus and species of Planopinae (Xenarthra: Tardigrada) from the Miocene of Santa Cruz Province, Argentina". Zootaxa. 3694: 565–578. doi:10.11646/zootaxa.3694.6.4. hdl: 11336/18925 . ISSN   1175-5326. PMID   26312311.
  5. McKenna, Malcolm C.; Bell, Susan K. (1997-10-17). Classification of Mammals: Above the Species Level. Columbia University Press. ISBN   978-0-231-52853-5.
  6. Gaudin, T. J. (2004). "Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): The craniodental evidence". Zoological Journal of the Linnean Society. 140 (2): 255–305. doi: 10.1111/j.1096-3642.2003.00100.x .