Eremotherium

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Eremotherium
Skeletal reconstruction of Eremotherium in the National Museum of Natural History, Washington, DC

Skeletal reconstruction of Eremotherium in the National Museum of Natural History , Washington, DC

Temporal occurrence
Pliocene to late Pleistocene
2.6 million years to 11,000 years
Locations
Systematics
Sub-articulated animals (Xenarthra)
Tooth arms (pilosa)
Sloths (folivora)
Megatherioidea
Megatheriidae
Eremotherium
Scientific name
Eremotherium
Spillmann , 1948

Eremotherium is an extinct genus of sloths from the Megatheriidae family. It livedin northern South and southern North America during the Pleistocene , around 2.5 million years ago to 11,000 years ago. Eremotherium was mainly foundin tropical and subtropical flatlands and lived there in partly open and closed landscapes, while its closest relative Megatherium lived in temperate or higher altitudes. Both genera reached the size of today's elephants and are among the largest mammals in America. Characteristic for Eremotherium was its robust physique with comparatively long limbs and fore and hind feet with three fingers each - especially in later representatives. The skull, however, had a relatively delicate structure, the dentition consisted of uniformly shaped, high-crowned teeth. Like today's sloths, Eremotherium was a pure herbivore that fed on leaves and grasses. The animals were able to adapt their food consumption to the respective local and climatic conditions. Finds of the genus are very common, the sites of Toca das Onças in Brazil and Daytona Beach in Florida are outstanding. The two best known species of the genus are Eremotherium laurillardi and Eremotherium eomigrans .

features

General and size

Similar to the closely related Megatherium , Eremotherium reached a total length of 5 to 6 m. The weight was originally given as 3 t, calculations based on a thighbone almost 74 cm long resulted in a weight of 3.96 t, but significantly longer femora from Eremotherium are known. Other weight estimates range up to 6.55 t. In general, a body weight similar to that of Megatherium is assumed today , which varied between 3.8 and 6 t for the largest representatives. It is possible that Eremotherium also exceeded Megatherium in weight, as it was built much more robustly than this one and had longer limbs. But in any case it belongs in addition to from Eurasia immigrant trunk animals of the largest land-dwelling mammals that time in America . As a ground-dwelling sloth, like many of its phylogenetic predecessors , it had relatively shorter and stronger limbs than today's tree-dwelling sloths and also had a longer tail.

Skull and dentition features

Eremotherium's skull was large and massive, but lighter in weight compared to Megatherium . A complete skull measured 65 cm in length and was up to 33 cm wide at the zygomatic arches . In the area of ​​the back teeth it reached 19 cm. The forehead line was clearly straight and not as wavy as with Megatherium . On the nasal bone it had cuts compared to the skull of Megatherium , which made it look like a truncated cone. There were other differences to Megatherium in the intermaxillary bone : Eremotherium had a triangular shape and was only loosely connected to the upper jaw; in its larger relative, the middle jaw bone had a square shape, as was a fixed connection to the upper jaw. The occiput had a semicircular shape in the rear view and sloped backwards in the side view. The joint surfaces as the point of attachment of the cervical spine bulged far outwards and were relatively larger than in the tree sloths and numerous other ground sloths. The parietal bones had a far outwardly curved shape, which was partly caused by the large cranial cavity with a volume of 1600 cm³. In contrast to today's sloths, the strong zygomatic arch was closed, but like this one it had a downward and a rearward-pointing, massive bony outgrowth that started from the front arch base. In addition, a third protrusion protruded diagonally upwards. The downward-pointing bony process was significantly steeper than that of other sloths. The eye window was flat and small and a little deeper than that of the Megatherium or today's sloths.

The lower jaw was about 55 cm long, both halves were connected by a strong symphysis , which lengthened in the shape of a spatula towards the front and ended with a rounded end. Typical for all representatives of the Megatheriidae was the clearly downward curve of the lower edge of the bone body, which was created by the different lengths of the teeth. In Eremotherium , the lower jaw was 14.5 cm deep below the symphysis, 15 cm below the second tooth and 12.5 cm below the fourth. The strength of the curvature of the lower edge of the lower jaw increased significantly in the course of individual development, but the ratio of the height of the lower jaw body to the length of the row of teeth remained largely the same. This differs markedly from Megatherium , in which the height of the lower jaw not only increased in absolute terms, but also relatively in relation to the length of the row of teeth. The body of the lower jaw was also very thick, leaving little space for the tongue. The crown process rose up to 27 cm, the articular process was only slightly lower. At the rear, lower end there was a strong, clearly notched angular process, the upper edge of which was approximately level with the occlusal plane. A strong mental foramen was evident at the front edge of the lower jaw . The teeth were typical of sloths, but, unlike today's representatives, consisted of completely homodontic teeth, which is a characteristic feature of Megatheria. Each branch of the jaw had 5 teeth in the upper jaw and 4 teeth in the lower jaw, so Eremotherium had 18 teeth in total . They resembled molars and, except for the foremost, were square, with large individuals mostly a good 5 cm long and with a height of 15 cm very high crown ( hypsodontal ). They had no roots and grew all of life. The enamel was also missing . On the chewing surface, however, there were typically two transversely positioned, sharp-edged ridges that supported the grinding of the food. The entire upper row of teeth was up to 22 cm long, the lower one reached up to 21 cm.

Features of the body skeleton

Hand of E. laurillardi with the characteristic three fingers

The body skeleton is largely known in full. The tail comprised 19 to 20 vertebrae, which corresponds to the number of other mammals with morphologically and functionally reduced tails, such as the cloven-hoofed and odd-toed ungulates . But it was much longer than today's sloths. The vertebrae were massive, both on the vertebral bodies and on the lateral transverse processes . However, the length of the vertebral bodies was compressed, so that the tail looked rather short overall and generally did not exceed the length of the lower limb sections. The humerus was a long tube with a massive lower joint end. The total length was around 79 cm. Distinctive, burr-like muscle attachment points on the central shaft were typical. The forearm bones were much shorter in length, with the radius around 67 cm and the cubit 57 cm in length. The thigh bone was massive and had the broad structure characteristic of Megatheria and was narrowed in front and behind. It had an average length of 74 cm, the largest bone found so far was 89.5 cm long and 45.1 cm wide. The third trochanter, a prominent muscle attachment point on the shaft, which is typical of secondary articular animals , was absent in Eremotherium as in all other megatheria. The tibia and fibula were only fused together at the upper end and not also at the lower end, as was the case with Megatherium . The shin was about 60 cm long. The forelegs ended in hands with three rays (III to V). The two inner rays (I and II) were fused together with some elements of the wrist , such as the large polygonal bone to form a unit, the metacarpal-carpal complex (MCC). Thus Eremotherium differs significantly from Megatherium and other closely related forms that had four-pointed hands. In Eremotherium, the metacarpal bone of the third ray was the shortest and measured 19 cm in length, those of the fourth and fifth were almost the same length with 28 and 27.5 cm, respectively. The terminal phalanx (the third phalanx) of the third and fourth ray had a long and pointedly curved shape, which accordingly suggests long claws, the fifth ray only had two phalanges and therefore had no claw formed there. (An exception is the older form E. eomigrans , whose hands, unlike other Megatheria, were still five-pronged, with claws on rays I to IV.) As with all Megatheria, the foot was also three-pronged (rays III to V). It was like the hand with an extremely short metatarsal bone of the third ray. That of the fourth ray reached 24 cm, that of the fifth 21 cm. In contrast to the hand, only the central ray (III) had three phalanges with an end phalanx that carried a long claw. The two outer rays had only two toe phalanges. This structure of the foot is typical of developed megatheria.

Distribution and important fossil finds

Finds of Eremotherium are widespread, but are limited to the tropical and subtropical lowland regions of South and North America . They come from more than 130 sites. In South America, fossil remains of the genus can be found from northern Peru via Ecuador , Colombia to Guiana and in the Amazon basin . So far, no finds have been found south of the Brazilian state of Rio Grande do Sul . Here and further south in the pampas region as well as in higher mountain areas, Megatherium was mainly widespread. In North America the occurrence reached from Georgia over Texas to South Carolina and on the east coast from Florida to New Jersey . The oldest known finds come from the US state Florida and belong to the species E. eomigrans . They were found among others in Haile in a water-filled sinkhole (location 7C), 6 km northeast of Newberry in Alachua County . They comprise several partial skeletons and several isolated bones and are between 2.1 and 1.8 million years old, which corresponds to the beginning of the Lower Pleistocene . Including other finds from Florida, such as the Kissimmee River , but which are too unspecific to be able to assign them to an exact species, the maximum age would be estimated at 2.5 million years and thus in the transition from the Pliocene to the Pleistocene. The discovery of a foot bone from El Breal de Orocual in Venezuela may be the same .

Skeletal reconstruction of E. laurillardi based on the finds from Daytona Beach

Much more common and widespread are fossil remains of the mid to late Pleistocene form E. laurillardi . The Toca das Onças cave site in the Brazilian state of Bahia is significant , where over 4000 finds from at least 36 individuals of all ages, including 14 complete skulls, have been preserved. The remains are between 15,000 and 16,000 years old. A sinkhole near Jirau in the north-eastern Brazilian state of Ceará was also found to be very rich . Here over 1140 fossil remains of E. laurillardi were found , which can be assigned to at least 19 individuals. Other extensive finds, such as skull fragments, lower jaw and parts of the musculoskeletal system, have come down to us from Uberaba in the Brazilian state of Minas Gerais. The coastal region of Ecuador is very rich in finds. The Machalilla site on the Rio Caña south of the city of Manta alone yielded 137 fossil remains from all parts of the body of E. laurillardi . From the Santa Elena peninsula comes a 65 cm long skull, which was used to establish the genus. On the same peninsula the natural barg asphalt pit of Tanque Loma least 1,000 bone fragment, of which 660 were analyzed in detail. A good 86% belong to Eremotherium alone and are distributed among almost two dozen individuals. The deposits are between 23,500 and 17,000 years old. With over 40 fossil finds of all body parts, Miramar on the north coast of Peru is also very rich. In La Huaca , a little further south, there are still a dozen finds, and at around 304,000 years they are relatively old. In this region Eremotherium may have appeared sympatric with Megatherium . Eremotherium has also come down to us from the Peruvian Amazon region . Outstanding here is a right talus from Tarapoto in the San Martín region , which is the largest known to date with a length of 28.5 cm (other large astragali reach 22.4 to 23.8 cm in length). It differs morphologically slightly from other spring bones of Eremotherium , which is explained by its enormous size, but so far there are no comparative finds with similar dimensions. The most important finds in North America include those from Daytona Beach in Florida. 1400 fossil remains of at least 11 individuals have been discovered here. Furthermore, would El Bajión in the Mexican state of Chiapas worth over 70 discoveries, including limbs, vertebrae and jaw fragments. They belong to a total of four individuals.

Paleobiology

Locomotion

The predominantly four-footed locomotion took place on inwardly turned feet, the entire weight came to lie on the outer, fifth and possibly fourth beam ( pedolateral ), whereby, among other things, the ankle bone was subject to massive changes. The hands were also twisted in, this position was somewhat similar to the forefeet of the Chalicotheriidae , which are also clawed , a now extinct group of large mammals belonging to the odd-toed ungulate . It also suggests that locomotion was rather slow. Even digging activities, as demonstrated for other large ground sloths, could not be carried out with it, which can also be seen from the structure of the forearm, just as the manipulation of objects was minimized by the restricted mobility of the fingers to each other. However, Eremotherium could stand up on its hind legs and pull branches and twigs with its hands, for example to reach the foliage of tall trees for food, as well as defensive blows with its long claws. The erection was supported by the strong tail, similar to what is still the case with armadillos and anteaters today. The massive caudal vertebrae in the front area of ​​the tail suggest a strong musculature. Among other things, this affects the coccygeus muscle , which attaches to the ischium and fixes the tail. On the other hand, the epaxial muscles that could cause the tail to straighten were less well developed.

nutrition

Eremotherium had extremely high-crowned teeth, which however did not reach the dimensions of those of Megatherium . Since the teeth lack enamel , this hypsodontia may not be an expression of a specialization in grass for food, unlike mammals with enamel in their teeth. The different expression of the high crown in both large ground sloths is more likely to be found in the adaptation to different habitats - more tropical flatlands with Eremotherium and more temperate regions with Megatherium . Various isotope analyzes on the teeth of Eremotherium therefore advocate the view of a herbivore adapted to a mixed vegetable diet, who preferred grass as food in open landscapes, but leaves in largely closed forests. Finds of coprolites have shown that smaller branches were sometimes chewed . More detailed isotope studies on the growth zones of a tooth from Cara Blanca in central Belize were able to reconstruct the feeding habits of an animal that died around 27,000 years ago. The individual therefore experienced a long dry period of around nine months in the last year of his life, which was framed by two shorter periods of wetness. The oxygen and carbon isotope ratios produced different, sometimes contradicting courses for the rainy and dry seasons. As a result, it can be assumed that during the rainy season, the animal mainly consumed C 4 plants such as a wide variety of grasses, but also bushes, such as logs or so-called CAM plants , such as epiphytic bromeliads . In the dry season, however, when the C 4 and CAM plants grew more sparsely, the main component of the diet consisted of C 3 plants . Obviously, Eremotherium was relatively flexible in its feeding behavior and reacted under local conditions and with varying climatic conditions with a correspondingly adapted diet.

As with numerous herbivores, the lower jaw-skull connection was due to the protruding articular process of the lower jaw above the dental chewing plane. Reconstruction of the chewing apparatus showed that lateral chewing movements predominated. This differs from the Megatherium , which is roughly the same size , in which a predominance of vertical chewing movements is assumed. The lateral chewing movements result, among other things, from the very deep insertion of the masseter muscle at the lower end of the descending branch of the zygomatic arch, which limits more extensive movements. In addition, the form of the mandibular-skull connection advocates these movements, as the mandibular joint is clearly wide and arched, while the glenoid pit on the skull has a more rectangular and indented shape. Ultimately, the shape of the teeth with their deep, transverse valleys between the high ribs also supports laterally oriented chewing. This is confirmed by similarly oriented signs of wear on the tooth surfaces. It is unclear whether a very long and flexible tongue was used when eating, as is often assumed. For the closely related genus Megatherium and some other large, extinct ground sloths, studies of the hyoid bone show that it could not support such a tongue because of its special construction. However, due to some anatomical features of Eremotherium, such as the broad, slightly arched lower jaw symphysis and the presence of a small mouth opening, a long, narrow tongue is assumed even with completely closed teeth.

Population structure

Due to several finds of several individuals at individual sites, such as in El Bajión in Chiapas in Mexico with four animals or in Tanque Loma on the Santa Elena Peninsula in Ecuador with 22 individuals, some scientists are discussing whether Eremotherium possibly lived in smaller, herd-like groups wandered around. In Tanque Loma in particular, the identified individuals are made up of at least 15 adult animals and six young animals. All of them came to light in a rich, narrowly delimited area and are therefore interpreted as belonging together. The possible group gathered at a watering point and died there relatively suddenly due to an unknown event. On the other hand, partially increased occurrences of Eremotherium such as the 19 individuals from the sinkhole of Jirau in Brazil are viewed as a longer-lasting accumulation. In the case of the equally huge ground sloth Lestodon from central South America, experts interpret the mass accumulations of remains of various individuals, sometimes as an indication of a phased group formation. Today's sloths live solitary and are comparatively true to location.

Soft tissues, sexual dimorphism and clinical pictures

Due to the life in forests and partly open landscapes of the tropical-subtropical flatlands, it is discussed whether Eremotherium had a pronounced fur, as is often shown in living reconstructions, known from modern sloths and is fossilized by several extinct forms. However, the enormous body size and the associated and necessary thermoregulation speak against it and in favor of a more or less bare skin, similar to that of other large, modern herbivores, such as elephants , rhinos or hippos . In terms of body size, significant differences can be seen between individual adult individuals, which affect populations in South and North America alike. Measurements on different bones, such as the talus or the thigh bone, showed deviations of up to 35% within different measurement distances. This is explained by a strong sexual dimorphism , with the larger and more robust individuals possibly representing males, the smaller females. The differences in size have been demonstrated above all for the better-known species E. laurillardi and E. eomigrans .

Pathological findings in the form of arthritis , which can mainly be attributed to the large body mass, are relatively common and occur, among other things, on the caudal vertebrae. On the other hand, bone changes in the cervical spine of a similar type, as in a second cervical vertebra ( axis ) from the Brazilian state of Pernambuco , are rather rare and unusual , since these are not due to the enormous weight. Disease and age-related symptoms such as pseudogout , Schmorl cartilage nodules and spondylosis could be identified in individual other individuals .

Relationship with the Early Paleo-Indians of America and Extinction

The disappearance of eremotheria coincides with the Quaternary wave of extinction and must be classified in this context. The latest Eremotherium finds include that of Itaituba on the Rio Tapajós , a tributary of the Amazon . They date to 11,340 BP and include several skull and mandibular fragments. The finds from Barcelona in the Brazilian state of Rio Grande do Norte fall in a similar period with 11,324 to 11,807 years ago. The extent to which hunting by Paleo-Indians contributed the cause is the subject of an unfinished, sometimes controversial, scientific discourse, but joint finds of Eremotheriun remains and remains of the early inhabitants of America are rare. A possible indication of a meeting with humans is a possibly worked tooth of Eremotherium from a sinkhole on the grounds of the São José farm in the Brazilian state of Sergipe . However, there is more leeway here for interpretation: Since the earliest evidence of settlement in the region dates back to the early Holocene , it is unclear whether the people only picked up the piece or killed the animal themselves, but there are no finds of eremotheria from the Known early holocene. The anthropogenic origin of the brands is also discussed.

Systematics

Internal systematics of the Megatheriinae according to De Iuliis et al. 2009 and Pujos et al. 2013
 Megatheriinae  


 Megathericulus


   

 Anisodontherium



   


 Megatheriops


   

 Pyramiodontherium



   
 Eremotherium  

 E. eomigrans


   

 E. laurillardi



 Megatherium  

 M. ( Megatherium )


   

 M. ( Pseudomegatherium )






Template: Klade / Maintenance / Style

Eremotherium is a genus from the extinct family of Megatheriidae , which includes large to very large representatives from the suborder of the sloths (Folivora). The Megatheriidae in turn form together with the Megalonychidae and the Nothrotheriidae a more closely related group, the superfamily Megatherioidea . According to the classical conception based on skeletal anatomy, the Megatherioidea represent one of the two major lines within the sloth, the second is found in the Mylodontoidea . A third line, the Megalocnoidea , could be identified with the help of molecular genetic and protein-based analyzes. The Megatherioidea also include the three-toed sloth ( Bradypus ), one of the two species of tree-dwelling sloths that still exist today. One of the closest relatives of Eremotherium within the Megatheriidae is the Megatherium , which is similar in size but is more common in open landscapes and represents the sister taxon . Pyramiodontherium and Megatheriops are also closely related . All of these forms form the subfamily of Megatheriinae , which make up the developed large ground sloths. The direct phylogenetic ancestor of Eremotherium is so far unknown. Possibly he is related to Proeremotherium from the Codore Formation in Venezuela, which dates to the Pliocene . The genus has numerous characteristics that are assumed for the predecessor form of Eremotherium . Little is known about the origin of the genus Eremotherium . Maybe it developed in the late Pliocene in South America, where few sites are known from this period, and reached by the emergence of the Isthmus of Panama , that is the formation of the land bridge between North and South America, as part of the Great American Faunentauschs also the southern regions of North America, where the oldest finds come from. The discovery of Proeremotherium also suggests that these or other close ancestors of Eremotherium first migrated to North America. There then, according to the findings, Eremotherium developed and migrated back to South America, similar to what is assumed for Glyptotherium from the group of Glyptodontidae .

There are three types recognized today:

The first known finds of Eremotherium from the publication by Peter Wilhelm Lund in 1842. A and B: teeth of a fully grown animal; C and D: teeth of a young animal, the two form the holotype specimens of E laurillardi

Numerous other species such as E. carolinense , E. mirabile or E. cucutense have been described in the past, but are mostly synonymous with the type species E. laurillardi . This was set up in 1842 by Peter Wilhelm Lund based on two teeth (copy number ZMUC 1130 and 1131) from Lapa Vermella, a cave in the valley of the Rio das Velhas in the Brazilian state of Minas Gerais under the name Megatherium laurillardi . As a reason for this, Lund referred to the size of the teeth, which were only a quarter of the size of Megatherium americanum , the largest representative of Megatherium . Today the teeth are considered to belong to juveniles of E. laurillardi and adult specimens of the species reached or exceeded the size of M. americanum . Two years earlier, Lund had already presented teeth from the same locality, which he assigned to Megatherium americanum based on their dimensions ; he illustrated them together with the smaller teeth in his publication from 1842. They also belong to Eremotherium today . In the same year of Lund's publication (1842) Richard Harlan used today's synonym Chelonia couperi . Harlan had described an alleged thigh bone and placed it in the genus Chelonia of the tortoise . It was not until 1977 that it was recognized that it was actually a clavicle of Eremotherium . It is unknown which publication appeared first - according to the regulations of the ICZN , the species name of the first publication would have priority even if it was added to a different genus - but the name E. couperi is largely unknown, so that most researchers E. laurillardi to use.

There is, however, a scientific dispute according to which Lund's teeth belong to fully grown animals, which would therefore be significantly smaller than the largest members of Eremotherium . As a result, the species E. laurillardi would represent a dwarf form of the Megatheria, while the large form of Eremotherium would have to be called E. rusconii . The species was established by Samuel Schaub in 1935 as Megatherium rusconii based on finds from Venezuela . However, this view is mostly contradicted and argued that at least in the late Pleistocene in South and North America only one large species existed, E. laurillardi , which showed a strong sexual dimorphism . This is supported by the analysis of the extensive finds from Toca das Onças in Brazil and from Daytona Beach in Florida, which did not reveal any major differences between these two populations. The only two other recognized species are E. eomigrans and E. sefvei . The former has so far only been found in North America and reached a size similar to E. laurillardi , but dated to the Pliocene and Old Pleistocene and had a five-pointed hand instead of the three-pointed hand of the later representatives. From the latter, only a 39 cm long, morphologically very different, right thigh bone has survived, which comes from Ullama in Bolivia . Here the age can only be given generally as “Pleistocene”, but it is the smallest representative of Eremotherium and of all post- Miocene Megatheria.

The first scientific description of Eremotherium was made in 1948 by Franz Spillmann . He carried out it using a 65 cm long skull with an associated lower jaw, both finds come from the Santa Elena peninsula in Ecuador . Its species name used E. carolinense , assigned to the town of Carolina near the site, but is not recognized. The generic name Eremotherium is derived from the Greek words ἔρημος ( erēmos "steppe", "desert") and θηρίον ( thērion "animal"). It refers to the landscape of the find region reconstructed by Spillmann. In the following year Robert Hoffstetter introduced the genus Schaubia for Schaub's Megatherium rusconii , as he recognized characteristics that differed from Megatherium . Since this generic name was already taken, he renamed it Schaubitherium the following year . It was not until 1955 that he recognized similarities to Spillmann's Eremotherium and withdrew its name.

literature

  • Cástor Cartelle and Gerardo De Iuliis: Eremotherium laurillardi: The Panamerican Late Pleistocene Megatheriid Sloth. Journal of Vertebrate Paleontology 15 (4), 1995, pp. 830-841 ( online )
  • Cástor Cartelle and Gerardo De Iuliis: Eremotherium laurillardi (Lund) (Xenarthra, Megatheriidae), the Panamerican giant ground sloth: Taxonomic aspects of the ontogeny of skull and dentition. Journal of Systematic Palaeontology 4 (2), 2006, pp. 199-209, doi: 10.1017 / S1477201905001781
  • Virginia L. Naples and Robert K. McAfee: Reconstruction of the cranial musculature and masticatory function of the Pleistocene panamerican ground sloth Eremotherium laurillardi (Mammalia, Xenarthra, Megatheriidae). Historical Biology: An International Journal of Paleobiology 24 (2), 2012, pp. 187-206

Individual evidence

  1. ↑ a b Fernando Henrique de Souza Barbosa, Hermínio Ismael de Araújo-Júnior and Edison Vicente Oliveira: Neck osteoarthritis in Eremotherium laurillardi (Lund, 1842; Mammalia, Xenarthra) from the Late Pleistocene of Brazil. International Journal of Paleopathology 6, 2014, pp. 60-63, doi: 10.1016 / j.ijpp.2014.01.001 .
  2. ↑ a b c d e f Franz Spillmann: Contributions to the knowledge of a new gravigrade giant steppe animal (Eremotherium carolinense gen. Et sp. Nov.), Its habitat and its way of life. Palaeobiologica 8, 1948, pp. 231-279
  3. ^ A b H. Gregory McDonald: Paleoecology of extinct Xenarthrans and the Great American Biotic Interchange. Bulletin of the Florida Museum of Natural History 45 (4), 2005, pp. 313-333
  4. ↑ a b c Mario Andre Trindade Dantas, Alexander Cherkinsky, Herve Bocherens, Morgana Drefahld, Camila Bernardes and Lucas de Melo França: Isotopic paleoecology of the Pleistocene megamammals from the Brazilian Intertropical Region: Feeding ecology (d13C), niche breadth and overlap. Quaternary Science Reviews 170, 2017, pp. 152-163
  5. ↑ a b c Richard M. Fariña, Sergio F. Vizcaíno and Gerardo de Iuliis: Megafauna. Giant beasts of Pleistocene South America. Indiana University Press, 2013, pp. 1-436 (pp. 216-218) ISBN 978-0-253-00230-3
  6. ^ Sergio F. Vizcaíno, M. Susasna Bargo and Richard A. Fariña: Form, function, and paleobiology in xenarthrans. In: Sergio F. Vizcaíno and WJ Loughry (eds.): The Biology of the Xenarthra. University Press of Florida, 2008, pp. 86-99
  7. ↑ M. Susana Bargo, Sergio F. Vizcaíno, Fernando M. Archuby and R. Ernesto Blanco: Limb bone proportions, strength and digging in some Lujanian (Late Pleistocene-Early Holocene) mylodontid ground sloths (Mammalia, Xenarthra). Journal of Vertebrate Paleontology 20 (3), 2000, pp. 601-610
  8. ↑ a b c d e f Cástor Cartelle and Gerardo De Iuliis: Eremotherium laurillardi: the Panamerican Late Pleistocene Megatheriid sloth. Journal of Vertebrate Paleontology 15 (4), 1995, pp. 830-841
  9. ↑ a b c d e f g Cástor Cartelle and Gerardo De Iuliis: Eremotherium laurillardi (Lund) (Xenarthra, Megatheriidae), the Panamerican giant ground sloth: Taxonomic aspects of the ontogeny of skull and dentition. Journal of Systematic Palaeontology 4 (2), 2006, pp. 199-209
  10. ↑ a b c d e f g h Gerardo De Iuliis and Cástor Cartelle: A new giant megatheriine ground sloth (Mammalia: Xenarthra: Megatheriidae) from the late Blancan to early Irvingtonian of Florida. Zoological Journal of the Linnean Society 127, 1999, pp. 495-515
  11. ^ A b c d Virginia L. Naples and Robert K. McAfee: Reconstruction of the cranial musculature and masticatory function of the Pleistocene panamerican ground sloth Eremotherium laurillardi (Mammalia, Xenarthra, Megatheriidae). Historical Biology: An International Journal of Paleobiology 24 (2), 2012, pp. 187-206
  12. ↑ a b Cástor Cartelle, Gerardo De Iuliis and François Pujos: Eremotherium laurillardi (Lund, 1842) (Xenarthra, Megatheriinae) is the only valid megatheriine sloth species in the Pleistocene of intertropical Brazil: A response to Faure et al., 2014. Comptes Rendus Palevol 14, 2014, pp. 15-23
  13. ↑ a b Martine Faure, Claude Guérin and Fabio Parenti: Sur l'existence de deux espèces d'Eremotherium E. rusconii (Schaub, 1935) and E. laurillardi (Lund, 1842) dans le Pléistocène supérieur du Brésil intertropical. Comptes Rendus Palevol 13 (4), 2014, pp. 259-266
  14. ↑ a b M. Susana Bargo, Gerardo de Iuliis and Sergio F. Vízcaino: Hypsodonty in Pleistocene ground sloths. Acta Palaeontologica Polonica 51 (1), 2006, pp. 53-61
  15. ↑ a b c d e f g Giuseppe Tito: New remains of Eremotherium laurillardi (Lund, 1842) (Megatheriidae, Xenarthra) from the coastal region of Ecuador. Journal of South American Earth Sciences 26, 2008, pp. 424-434
  16. ↑ Gerardo De Iuliis: Toward the morphofunctional understanding of the humerus of Megatheriinae: The identity and homology of some diaphyseal humeral features (Mammalia, Xenarthra, Megatheriidae). Senckenbergiana biologica 83, 2003, pp. 69-78
  17. ↑ H. Gregory McDonald: Xenarthran skeletal anatomy: primitive or derived? Senckenbergiana biologica 83, 2003, pp. 5-17
  18. Jump up ↑ Gerardo De Iuliis and Cástor Cartelle: The medial carpal and metacarpal elements of Eremotherium and Megather-ium (Xenarthra: Mammalia). Journal of Vertebrate Paleontology 14, 1994, pp. 525-533
  19. ↑ a b c Giuseppe Tito and Gerardo De Iuliis: Morphofunctional aspects and paleobiology of the manus in the giant ground sloth Eremotherium Spillmann 1948 (Mammalia, Xenarthra, Megatheriidae). Senckenbergiana biologica 83 (1), 2003, pp. 79-94
  20. ^ Diego Brandoni, Alfredo A. Carlini, Francois Pujos and Gustavo J. Scillato-Yané: The pes of Pyramiodontherium bergi (Moreno & Mercerat, 1891) (Mammalia, Xenarthra, Phyllophaga): The most complete pes of a Tertiary Megatheriinae. Geodiversitas 26 (4), 2004, pp. 643-659
  21. ^ A b François Pujos and Rodolfo Salas: A systematic reassessment and paleogeographic review of fossil Xenarthra from Peru. Bulletin de l'Institut Français d'Etudes Andines 33 (2), 2004, pp. 331-377
  22. ↑ a b c Bruno Andrés Than-Marchese, Luis Enrique Gomez-Perez, Jesús Albert Diaz-Cruz, Gerardo Carbot-Chanona and Marco Antonio Coutiño-José: Una nueva localidad con restos de Eremotherium laurillardi (Xenarthra: Megateriidae) in Chiapas, Mexico : possible evidencia de gregarismo en la especie. VI Jornadas Paleontológicas y I Simposio de Paleontología en el Sureste de México: 100 años de paleontología en Chiapas, 2012, p. 50
  23. ↑ Ascanio D. Rincón, Gilberto E. Parra, Francisco J. Prevosti, Maria Teresa Alberdi and Christopher J. Bell: A preliminary assessment of the mammalian fauna from the Pliocene-Pleistocene El Breal de Orocual locality, Monagas State, Venezuela. Museum of Northern Arizona Bulletin 65, 2009, pp. 593-620
  24. ^ Andrés Solórzano, Ascanio D. Rincón and H. Gregory McDonald: A New Mammal Assemblage from the Late Pleistocene El Breal de Orocual, Northeast of Venezuela. Science Series 42, 2015, pp. 125-150
  25. ↑ Augusto S. Auler, Luís B. Piló, Peter L. Smart, Xianfeng Wang, Dirk Hoffmann, David A. Richards, R. Lawrence Edwards, Walter A. Neves and Hai Cheng: U-series dating and taphonomy of Quaternary vertebrates from Brazilian caves. Palaeogeography, Palaeoclimatology, Palaeoecology 240, 2006, pp. 508-522
  26. ↑ a b Hermínio Ismael de Araújo-Júnior, Kleberson de Oliveira Porpino, Celso Lira Ximenes and Lílian Paglarelli Bergqvist: Unveiling the taphonomy of elusive natural tank deposits: A study case in the Pleistocene of northeastern Brazil. Palaeogeography, Palaeoclimatology, Palaeoecology 378, 2013, pp. 52-74
  27. ↑ Agustín G. Martinelli, Patrícia Fonseca Ferraz, Gabriel Cardoso Cunha, Isabella Cardoso Cunha, Ismar de Souza Carvalho, Luiz Carlos Borges Ribeiro, Francisco Macedo Neto, Camila Lourencini Cavellani, Vicente de Paula Antunes Teixeira and Mara Lúcia da Fonseca Ferraz: First record of Eremotherium laurillardi (Lund, 1842) (Mammalia, Xenarthra, Megatheriidae) in the Quaternary of Uberaba, Triângulo Mineiro (Minas Gerais State), Brazil. Journal of South American Earth Sciences 37, 2012, pp. 202-207
  28. ↑ G. Cantalamessa, C. Di Celma, G. Bianucci, G. Carnevale, M. Coltorti, M. Delfino, G. Ficarelli, M. Moreno Espinosa, D. Naldini, P. Pieruccini, L. Ragaini, L. Rook , M. Rossi, G. Tito, D. Torre, G. Valleri and W. Landini: A new vertebrate fossiliferous site from the late Quaternary in San José on the north coast of Ecuador: preliminary note. Journal of South American Earth Sciences 14, 2001, pp. 331-334
  29. ^ Emily L. Lindsay and Eric X. Lopez R .: Tanque Loma, an new Late Pleistocene megafaunal tar seep locality from southwest Ecuador. Journal of South American Earth Sciences 57, 2015, pp. 61-82
  30. ↑ Emily L. Lindsay and Kevin L. Seymour, "Tar pits" of the Western Neotropics: Paleoecology, Taphonomy, and Mammalian Biogeography. Natural History Museum of Los Angeles County, Science Series 42, 2015, pp. 111-123
  31. ↑ a b c Emily L. Lindsey, Erick X. Lopez Reyes, Gordon E. Matzke, Karin A. Rice and H. Gregory McDonald: A monodominant late-Pleistocene megafauna locality from Santa Elena, Ecuador: Insight on the biology and behavior of giant ground sloths. Palaeogeography, Palaeoclimatology, Palaeoecology, 2020, p. 109599, doi: 10.1016 / j.palaeo.2020.109599
  32. ^ H. Gregory McDonald: Evolution of the Pedolateral Foot in Ground Sloths: Patterns of Change in the Astragalus. Journal of Mammal Evolution 19, 2012, pp. 209-215
  33. ^ Néstor Toledo, Gerardo De Iuliis, Sergio F. Vizcaíno and M. Susana Bargo: The Concept of a Pedolateral Pes Revisited: The Giant Sloths Megatherium and Eremotherium (Xenarthra, Folivora, Megatheriinae) as a Case Study. Journal of Mammalian Evolution 25 (4), 2018, pp. 525-537, doi: 10.1007 / s10914-017-9410-0
  34. ↑ Mário André Trindade Dantas, Rodrigo Parisi Dutra, Alexander Cherkinsky, Daniel Costa Fortier, Luciana Hiromi Yoshino Kamino, Mario Alberto Cozzuol, Adauto de Souza Ribeiro and Fabiana Silva Vieira: Paleoecology and radiocarbon dating of the Pleistocene megafauna of the Brazilian Intertropical Region. Quaternary Research 79, 2013, pp. 61-65
  35. ↑ Jean T. Larmon, H. Gregory McDonald, Stanley Ambrose, Larisa RG DeSantis and Lisa J. Lucero: A year in the life of a giant ground sloth during the Last Glacial Maximum in Belize. Science Advances 5 (2), 2019, p. Eaau1200 doi: 10.1126 / sciadv.aau1200
  36. ↑ Leandro M. Pérez, Néstor Toledo, Gerardo De Iuliis, M. Susana Bargo and Sergio F. Vizcaíno: Morphology and Function of the Hyoid Apparatus of Fossil Xenarthrans (Mammalia). Journal of Morphology 271, 2010, pp. 1119-1133
  37. ↑ Rodrigo L. Tomassini, Claudia I. Montalvo, Mariana C. Garrone, Laura Domingo, Jorge Ferigolo, Laura E. Cruz, Dánae Sanz ‑ Pérez, Yolanda Fernández ‑ Jalvo and Ignacio A. Cerda: Gregariousness in the giant sloth Lestodon (Xenarthra ): multi-proxy approach of a bonebed from the Last Maximum Glacial of Argentine pampas. Scientific Reports 10, 2020, p. 10955, doi: 10.1038 / s41598-020-67863-0
  38. ^ Adriano Garcia Chiarello: Sloth ecology. An overview of field studies. In: Sergio F. Vizcaíno and WJ Loughry (eds.): The Biology of the Xenarthra. University Press of Florida, 2008, pp. 269-280
  39. ^ Richard M. Fariña, Sergio F. Vizcaíno and Gerardo De Iuliis: Megafauna. Giant beasts of Pleistocene South America. Indiana University Press, Bloomington and Indianapolis, 2013, pp. 1–436 (pp. 259–260)
  40. ↑ Fernando H. de S. Barbosa, Kleberson de O. Porpino, Hermínio I. de Araújo Júnior, Lilian P. Bergqvist and Bruce M. Rothschild: Articular and vertebral lesions in the Pleistocene sloths (Xenarthra, Folivora) from the Brazilian Intertropical Region . Historical Biology: An International Journal of Paleobiology 31 (5), 2019, pp. 544-558
  41. ↑ Dilce de Fátima Rossetti, Peter Mann de Toledo, Heloísa Maria Moraes-Santos and Antônio Emídio de Araújo Santos, Jr .: Reconstructing habitats in central Amazonia using megafauna, sedimentology, radiocarbon, and isotope analyzes. Quaternary Research 61, 2004, pp. 289-300
  42. ↑ Mário André Trindade Dantas, Albérico Nogueira de Queiroz, Fabiana Vieira dos Santos and Mario Alberto Cozzuol: An anthropogenic modification in an Eremotherium tooth from northeastern Brazil. Quaternary International 253, 2012, pp. 107-109
  43. ↑ Alex Hubbe, Paulo M. Haddad-Martim, Mark Hubbe and Walter A. Neves: Comments on: “An anthropogenic modification in an Eremotherium tooth from northeastern Brazil”. Quaternary International 269, 2012, pp. 94-96
  44. ^ A b Gerardo De Iuliis, François Pujos and Giuseppe Tito: Systematic and Taxonomic Revision of the Pleistocene Ground Sloth Megatherium (Pseudomegatherium) Tarijense (Xenarthra: Megatheriidae). Journal of Vertebrate Paleontology 29 (4), 2009, pp. 1244-1251
  45. ^ François Pujos, Rodolfo Salas-Gismondi, Guillaume Baby, Patrice Baby, Cyrille Goillot, Julia Tejada and Pierre-Olivere Antoine: Implications of the presence of Megathericulus (Xenarthra: Tardigrada: Megatheriidae) in the Laventan of Peruvian Amazonia. Journal of Systematics Palaeontology 11 (7-8), 2013, pp. 973-991
  46. ↑ Timothy J. Gaudin: Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): the craniodental evidence. Zoological Journal of the Linnean Society 140, 2004, pp. 255-305
  47. ↑ Frédéric Delsuc, Melanie Kuch, Gillian C. Gibb, Emil Karpinski, Dirk Hackenberger, Paul Szpak, Jorge G. Martínez, Jim I. Mead, H. Gregory McDonald, Ross DE MacPhee, Guillaume Billet, Lionel Hautier and Hendrik N. Poinar : Ancient mitogenomes reveal the evolutionary history and biogeography of sloths. Current Biology 29 (12), 2019, pp. 2031-2042, doi: 10.1016 / j.cub.2019.05.043
  48. ↑ Samantha Presslee, Graham J. Slater, François Pujos, Analía M. Forasiepi, Roman Fischer, Kelly Molloy, Meaghan Mackie, Jesper V. Olsen, Alejandro Kramarz, Matías Taglioretti, Fernando Scaglia, Maximiliano Lezcano, José Luis Lanata, John Southon, Robert Feranec, Jonathan Bloch, Adam Hajduk, Fabiana M. Martin, Rodolfo Salas Gismondi, Marcelo Reguero, Christian de Muizon, Alex Greenwood, Brian T. Chait, Kirsty Penkman, Matthew Collins and Ross DE MacPhee: Palaeoproteomics resolves sloth relationships. Nature Ecology & Evolution 3, 2019, pp. 1121-1130, doi: 10.1038 / s41559-019-0909-z
  49. ^ Alfredo A. Carlini, Diego Brandoni and Rodolfo Sánchez: First Megatheriines (Xenarthra, Phyllophaga, Megatheriidae) from the Urumaco (Late Miocene) and Codore (Pliocene) Formations, Estado Falcón, Venezuela. Journal of Systematics Palaeontology 4 (3), 2006, pp. 269-278
  50. ^ Larry G. Marshall: Land Mammals and the Great American Interchange. American Scientist 76 (4), 1988, pp. 380-388 ( [1] )
  51. ^ Alfredo A. Carlini, Diego Brandoni and Rodolfo Sánchez: Additions to the knowledge of Urumaquia robusta (Xenarthra, Phyllophaga, Megatheriidae) from the Urumaco Formation (Late Miocene), Estado Falcón, Venezuela. Paläontologische Zeitschrift 82 (2), 2008, pp. 153–162
  52. ^ A b Gerardo De Iuliis and Antoine André: Eremotheriim sefvei nov. Sp. (Mammalia, Xenarthra, Megatheriidae) from the Pleistocene of Ulloma, Bolivia. Geobios 30 (3), 1997, pp. 453-461
  53. ↑ Peter Wilhelm Lund: Blik paa Brazil dyreverden för sidste jordomvaeltning. Det Kongelige Danske videnskabernes selskabs selskabs Naturvidenskkabelige og Mathematiske Afhandlinger 9, 1842, pp. 137–208 (pp. 143–190) ( [2] )
  54. ^ Peter Wilhelm Lund: Nouvelles recherches sur la Faune fossile de Brésil. Annales des sciences naturelles, Zoologie 2 série 13, 1840, pp. 310–319 ( [3] )
  55. ^ Claude Guérin and Martine Faure: La veritable nature de Megatherium laurillardi Lund, 1842 (Mammalia, Xenarthra): Un nain parmi les géants. Geobios 33 (5), 2000, pp. 475-488
  56. ↑ Franςois Pujos and Rodolfo Sallas A new species of Megatherium (Mammalia: Xenarthra: megatheriidae) from the Pleistocene of Sacaco and Tres Vantanas, Peru. Palaeontology 47 (3), 2004, pp. 579-604

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