Bradypus Tridactylus Research Articles

Prasiolopsis wulf-kochii (Prasiolales, Trebouxiophyceae), a New Species Occurring in Hairs of the Sloth Bradypus tridactylus.

The monotypic genus Prasiolopsis has been known for a long time, but is often overlooked because of difficulties in identification and the morphological variability between uniseriate filaments and cell packages forming pseudoparenchymatic thalli depending on age. We investigated a strain (SAG 84.81) originally denoted as Trichophilus welckeri, which was isolated from the hairs of the sloth Bradypus tridactylus, and compared it with other available strains of Prasiolopsis and of the sister genus Pseudomarvania. Our investigations clearly showed that this strain differed in morphology, especially of the chloroplast, from those originally described for Trichophilus. Phylogenetic analyses of the SSU and ITS rDNA sequences revealed that the strain SAG 84.81 is sister to several strains of P. ramosa within the Prasiola clade (Trebouxiophyceae). Using the ITS-2/CBC approach, we clearly demonstrated that this strain represented a new species of Prasiolopsis, which we proposed here as P. wulf-kochii. In addition, we evaluated the ITS-2/CBC approach by comparing it with the two species of Pseudomarvania. All investigated strains showed CBCs and HCBCs, which support their species delimitation. The sequencing data of Trichophilus welckeri available in GenBank were phylogenetically re-evaluated by including all representatives of the Ulotrichales (Ulvophyceae). Our analyses showed that these sequences formed their own lineage within this order.

Negative relationship between body mass and home range size in three-toed sloths of the Amazon rainforest

ABSTRACT The spatial use of habitat is key to understanding the ecology of animals and their area requirements. In the current study, the locations of 11 wild pale-throated three-toed sloths (Bradypus tridactylus) were tracked using GPS loggers across 92 days in a 776 ha forest fragment in the central Amazon. Although male home ranges were slightly smaller than those of females, there were no significant differences in size or its expansion patterns. For nine of 11 individuals, home range size reached a plateau within 45 days of study start, indicating that 45 days can be the basal minimum days to establish the home range size of B. tridactylus. There was a negative relationship between body mass and home range size in our study. This counterintuitive result may be caused by disparities in the food-exploring abilities between individuals. Smaller and presumably younger individuals, who have less experience, may require more time and a larger area in which to search for food, while older and more experienced individuals may be able to find food efficiently in a smaller area. Further work on the distribution of food plants and the food-exploring pattern of each animal in relation to age and/or size is thus encouraged.

Variations in dietary patterns of living sloths revealed by finite element analysis of jaws.

Although extinct sloths exhibited a wide range of dietary habits, modes of locomotion, and occupied various niches across the Americas, modern sloths are considered quite similar in their habits. The dietary habits of living sloths can be directly observed in the wild, and understanding the mechanical behavior of their jaws during chewing through finite element analysis (FEA) provides a valuable validation tool for comparative analysis with their extinct counterparts. In this study, we used FEA to simulate the mechanical behavior of sloth mandibles under lateral mastication loads, using it as a proxy for oral processing. Our research focused on the six extant sloth species to better understand their diets and validate the use of FEA for studying their extinct relatives. We found that all living sloths have the predominancy of low-stress areas in their mandibles but with significant differences. Choloepus didactylus had larger high-stress areas, which could be linked to a reduced need for processing tougher foods as an opportunistic generalist. Bradypus variegatus and Choloepus hoffmanni are shown to be similar, displaying large low-stress areas, indicating greater oral processing capacity in a seasonal and more competitive environment. Bradypus torquatus, Bradypus pygmaeus, and Bradypus tridactylus exhibited intermediary processing patterns, which can be linked to a stable food supply in more stable environments and a reduced requirement for extensive oral processing capacity. This study sheds light on extant sloths' dietary adaptations and has implications for understanding the ecological roles and evolutionary history of their extinct counterparts.

Zoonotic Giardia duodenalis assemblage A in northern sloth from Brazilian Amazon.

The parasite Giardia duodenalis infects a wide range of vertebrate hosts, including domestic and wild animals as well as humans. Giardia is genotyped into eight assemblages (A-H). Zoonotic assemblages A and B have already been identified in humans and wild and domestic animals (non-human primates and cats) from Brazilian Amazon and in the world. Due to its zoonotic/zooanthroponotic nature, surveillance initiatives and the definition of Giardia assemblages are important in order to characterise the epidemiological scenario and to implement further control measures. Determine assemblages of G. duodenalis in sloths from the Brazilian Amazon Region. Faecal parasitological examination of sloths from Amazonas State. Polymerase chain reaction (PCR) targeting the beta giardin (BG), and genes from multilocus sequence typing (MLST) scheme, amplicon sequencing and phylogenetic analysis. Here, we identified, by microscopy, Giardia in two northern sloths (Bradypus tridactylus). These two samples were submitted to molecular assays and it was revealed that both were infected by G. duodenalis assemblage A. Phylogenetic analysis showed that they belong to assemblage A within sequences from humans and wild and domestic animals. Therefore, besides showing, by the first time, the current presence of this parasite in sloths, our findings reveals that this wild animal species would be part of the zoonotic/zooanthroponotic scenario of this parasite in the Brazilian Amazon.

OCURRENCE OF Amblyomma spp. TICKS INFESTING Chironius bicarinatus, Bradypus tridactylus AND Puma concolor IN A ZOO OF MANAUS, AMAZONAS, NORTHERN BRAZIL

Ticks are ectoparasites arthropods distributed worldwide that can parasitize a wide range of animals, and transmitting pathogens such as bacteria, protozoa, helminths and viruses. The species that parasitize domestic animals are the most studied due to their sanitary importance, but little is known about most of the tick species that parasitize wild animals. Therefore, the aim of this study is to report the ocurrence of tick’s parasitism of the genus Amblyomma infesting Vine-snake (Chironius bicarinatus), Bentinho’s Sloth (Bradypus tridactylus) and Puma (Puma concolor) in a zoo in the city of Manaus, Amazonas, northern Brazil. Larvae of the genus Amblyomma as well as specimens of A. ovale, A. varium and A. gaeyi were identified. Therefore, it is possible to say that these tick species are present in Manaus, Amazonas, as well as it is the first report of specimens of Amblyomma spp. parasitizing Chironius bicarinatus. The scarcity of reports of this nature highlights the need for further studies on the distribution of these arthropods in different regions and host species.

Low-cost thermoregulation of wild sloths revealed by heart rate and temperature loggers

Arboreal herbivores require large digestive tracts for leaf fermentation and detoxification; however, they must also have a low body mass that allows them to reach the foliage. The three-toed sloth, Bradypus tridactylus, experiences this trade-off, as leaves comprise 97.2% of its diet. Their calorie intake is extremely low owing to the low available caloric density of leaves and slow digestive processes related to leaf fibre fermentation and secondary compound detoxification. Sloths may require a high body temperature to assist fermentation; however, thermogenesis is energy-consuming. To investigate how sloths accomplish thermoregulation using marginal energy, we attached heart rate (HR) and temperature loggers to wild B. tridactylus individuals inhabiting the Amazon rainforest and recorded their HR and body surface temperature (Tskin). Tskin changed with ambient temperature (Ta) but was higher than Ta in 99.2% of cases. Increases in Tskin and HR did not coincide, suggesting that the increases were not caused by thermogenesis. Instead, they may passively increase Tskin by selecting warmer microhabitats and sunbathing. Consequently, 90.5% of Tskin were within 27.6–36.0 °C while the Ta fluctuated between 21.5 and 42.9 °C. This low-cost thermoregulation results in a low HR. In this study, the mean HR during observation was approximately 38.4% of the expected value based on the mammalian allometric relationship between body mass and HR. Thus, these properties may contribute to the low metabolic rates of sloths, alleviating their restricted energy intake.

Two novel Ehrlichia (Rickettsiales: Anaplasmataceae) strains detected in ticks (Ixodida, Ixodidae) and opossums (Didelphimorphia: Didelphidae) in Argentina

The aim of this study is to determine if there is circulation of microorganisms of the genus Ehrlichia in opossums Didelphis albiventris and their ticks from the Humid Chaco in Argentina. Blood samples of 15 specimens of the opossum D. albiventris were analysed. Immature stages of the ticks Amblyomma ovale (Larvae=26; Nymphs=10), Amblyomma sculptum (Larvae=86; Nymphs=6) and Ornithodoros sp. cf. O. mimon (Larvae=90) were also analyzed. DNA was extracted individually from blood samples and ticks. Molecular detection of Ehrlichia agents was performed targeting two different loci: 16S rRNA and dsb gen. The phylogenetic analyses showed that the Ehrlichia sp. detected in D. albiventris in this study is identical to Ehrlichia sp. strain Natal previously detected in two marsupials from Brazil. Furthermore, a new Ehrlichia strain was amplified from an A. ovale nymph (named as Ehrlichia sp. strain El Bagual) which is phylogenetically closely related to a strain of Ehrlichia sp. detected in Bradypus tridactylus in Brazil. The findings of the current study represent the first report of these two strains of Ehrlichia for Argentina, showing that the diversity of Ehrlichia spp. is greater than previously assumed. Further studies should determine the epidemiological relevance of these findings.

Lazy thermoregulators take body temperature regulation shortcuts

Sloths are a physiological conundrum tiptoeing a fine, physiological line. As herbivores, sloths get all of their nutrients and calories from a diet of low-nutritional leaves, leaving them with relatively few calories to burn for bodily processes after foraging. (Imagine how much energy you would have after eating nothing but unflavoured rice cakes.) Because sloths do not obtain many nutrients or calories from their diet and they use what little energy they have to gather and digest that poor-quality food, it would make sense that they cut corners on other physiological processes, such as body temperature regulation. Daisuke Muramatsu, with collaborators from Kyoto University, Nara University of Education, Nagoya University and Hokkaido Research Center, Japan, and Universidade Federal do Amazonas, Brazil, investigated the body temperature patterns of wild sloths in the Amazon rainforest of Brazil by monitoring the heart rate and skin temperature in free-ranging pale-throated sloths (Bradypus tridactylus) to find out how cheaply sloths regulate their body temperature on their low energy budget.The researchers attached heart rate monitors and temperature data loggers to 34 free-ranging sloths. They caught the animals near the Federal University of Amazonas in Brazil by climbing trees and gently taking the relatively undisturbed and unprotesting individuals back to the field lab. There, they used a custom-made harness to attach a modified sloth-friendly Fitbit to monitor each animal's heart rate, a temperature data logger for skin temperature measurements and a VHF transmitter to locate the individual animal to retrieve the precious data loggers. After attaching the harnesses, they released the sloths back to the trees where they had been captured and installed a temperature data logger on the trunk of the tree to measure the temperatures that each sloth experienced. Five days later, the scientists returned to the area and normally the animals had not moved too far.Analysing the information stored by the skin temperature data loggers, the team discovered that the sloths were always slightly warmer than the trunk temperatures, but those elevated skin temperatures did not appear to be very costly for the animals, as their heart rates did not increase with the temperature. Because the researchers don't know exactly where the sloths were hanging out during each temperature measurement, they assumed that perhaps the sloths were basking in sunny spots when their body temperatures were warmer. The sloths seem to be taking an easy option for maintaining their body temperature. Instead of increasing heart rate or using up expensive fuel to increase or maintain their body temperature, the animals were probably relying more on the sun and environment to do that work for them. This dependence on basking could help explain how sloths are able to maintain their body temperature cheaply instead of constantly burning expensive fuel when on such a tight energy budget.However, this study, posted online as a preprint at Social Science Research Network, has not yet been peer reviewed, so we should be cautious about some of the researchers’ conclusions. Referring to the sloths’ skin temperatures as body temperatures could lead to some incorrect conclusions about body temperature regulation, as the skin temperatures recorded by Muramatsu and colleagues are likely very different from core body temperatures. Skin temperatures tend to overestimate core temperature during warm environmental temperatures and underestimate it in cool conditions. Regardless, sloths are an exciting study species in which to study body temperature regulation, as they must strike a delicate balance between staying warm enough to keep their fermenting digestive microbiome happy, but doing so in a slow and measured way.

Molecular investigation of haemotropic mycoplasmas and Coxiella burnetii in free-living Xenarthra mammals from Brazil, with evidence of new haemoplasma species.

Although mammals of the superorder Xenarthra are considered hosts of a wide range of zoonotic agents, works aiming at investigating the role of these animals as hosts for bacteria with zoonotic potential are rare. The present study aimed to investigate the occurrence and molecularly characterize Coxiella burnetii and haemoplasma (haemotropic mycoplasmas) DNA in blood and spleen samples from 397 free-living Xenarthra mammals (233 sloths, 107 anteaters and 57 armadillos) in five Brazilian states (Mato Grosso do Sul, São Paulo, Pará, Rondônia and Rio Grande do Sul). All biological samples from Xenarthra were negative in the qPCR for Coxiella burnetii based on the IS1111 gene. The absence of C. burnetii DNA in blood and spleen samples from Xenarthra suggests that these mammals may not act as possible hosts for this agent in the locations studied. When performed conventional PCR assays for the endogenous (gapdh) mammalian gene, 386 samples were positive. When screened by molecular assays based on the 16S rRNA gene of haemoplasmas, 81 samples were positive, of which 15.54% (60/386) were positive by conventional PCR and 5.44% (21/386) were positive by real-time PCR; three samples were positive in both assays. Of these, 39.74% (31/78) were also positive for the 23S rRNA gene and 7.69% (6/78) for the haemoplasma RNAse P gene. Among the samples positive for haemoplasmas, 25.64% (20/78) were obtained from anteaters (Tamandua tetradactyla and Myrmecophaga tridactyla), 39.74% (31/78) from sloths (Bradypus tridactylus, Bradypus sp. and Choloepus sp.) 34.61% (27/78) from armadillos (Priodontes maximus, Euphractus sexcinctus and Dasypus novemcinctus). A haemoplasma 16S rRNA sequence closely related and showing high identity (99.7%) to Mycoplasma wenyonii was detected, for the first time, in B. tridactylus. Based on the low identity and phylogenetic positioning of 16S rRNA and 23S rRNA sequences of haemoplasmas detected in anteaters and armadillos, the present study showed, for the first time, the occurrence of putative new Candidatus haemotropic Mycoplasma spp. ("Candidatus Mycoplasma haematotetradactyla" and "Candidatus Mycoplasma haematomaximus") in Xenarthra mammals from Brazil.

Q fever epidemic in Cayenne, French Guiana, epidemiologically linked to three-toed sloth.

A Q fever epidemic occurred in 2013 in a small military residential area in Cayenne, French Guiana. A retrospective cohort study was conducted to identify Q fever risk factors. Confirmed acute Q fever case was defined as positive serology (IgM ≥ 50 and phase II IgG ≥ 200) and/or positive qPCR on serum or blood. In addition, wild mammals were captured at the study site and tested by serology and real-time PCR performed on blood, vaginal swabs and ticks. The attack rate was 20 percent (11/54). All the cases were symptomatic with fever >38.5 °C and community-acquired pneumonia for four cases. Log binomial multivariate models identified two independent risk factors associated with Q fever: to clean the house (RRa = 7.5 CI95% [1.03-55.3]) and to carry a three-toed sloth in arms (RRa = 2.6 CI95% [1.1-5.8]). Eighteen marsupial individuals were captured, all PCRs were negative but 17% (3/18) had a positive serology. Another study conducted after the epidemic found only one (1/4) three-tooth sloth (Bradypus tridactylus) with feces highly infectious for C. burnetii MST17. The same strain C. burnetii genotype 17 has been laboratory- confirmed in this mammal and in human cases. These results support the implication of three-toed-sloth in this epidemic. Human contamination mainly occurs through inhalation of infectious aerosols as suggested by high relative risk associated with house cleaning activities and pulmonary forms of the disease, and through direct contact with three- toed-sloth. Positive serological results among marsupials confirm wildlife exposure and suggest a more complex sylvatic transmission cycle among wild mammals.

Tick fauna of wild animals received and attended at the Santarém Zoological Park, western Pará State, Brazil

ABSTRACT: Ticks are known worldwide for parasitizing a number of wild hosts. However, few studies have been conducted on ticks in zoos in Brazil. The objective of the present study was to collect, identify, and report the parasitic tick fauna found on wild Amazon animals received and attended at the Santarém Zoological Park from September 2004 to September 2013. In all, 56 animals, including 26 mammals and 30 reptiles, were sampled, from which 1172 ticks were collected and identified, comprising 862 adults, 284 nymphs, and 26 larvae. Nymphs of Amblyomma geayi on three-toed sloth (Bradypus tridactylus), adults of Amblyomma longirostre on black dwarf porcupine (Coendou nycthemera), and nymphs of Amblyomma naponense on southern tamandua (Tamandua tetradactyla) were identified for the first time in the country in the present study. Although, the North region is the largest among the five Brazilian regions, this is the first study conducted with ticks and animals attended in a zoo in the Brazilian Amazon.

Novel Anaplasma and Ehrlichia organisms infecting the wildlife of two regions of the Brazilian Amazon

During 2009–2012, wild animals were sampled in the Amazon biome of Brazil. Animal tissues and blood were tested by polymerase chain reaction (PCR) assays targeting DNA of the bacterial family Anaplasmataceae (genera Anaplasma, Ehrlichia, Wolbachia) and the genus Borrelia. Overall, 181 wild animals comprising 36 different species (2 reptiles, 5 birds, and 29 mammals) were sampled. All birds and reptiles were negative by all PCR assays, as well as all mammals for the Borrelia PCR assay. Anaplasmataceae agents were searched by PCR assays targeting two different genes, the ribosomal 16S rRNA gene and the protein-coding dsb gene. Three dsb closely related haplotypes were generated from 3 white-lipped peccaries (Tayassu pecari). In a phylogenetic analysis inferred from dsb partial sequences, these haplotypes grouped with previously reported Ehrlichia haplotypes from jaguar (Panthera onca) and horse from Brazil, suggesting that they could all represent a single species, yet to be properly characterized. A unique dsb haplotype was generated from a sloth (Bradypus tridactylus), and could also represent a different Ehrlichia species. All these dsb haplotypes formed a clade sister to the Ehrlichia ruminantium clade. Three distinct 16S rRNA gene haplotypes were generated from a wild guinea pig (Cavia sp.), a woolly mouse opossum (Micoureus demerarae), and two from robust capuchin monkeys (Sapajus sp.). In a phylogenetic analysis inferred from 16S rRNA gene partial sequence, these haplotypes grouped within the Wolbachia clade, and are likely to represent Wolbachia organisms that were infecting invertebrate metazoarians (e.g., filarids) associated with the sampled mammals. Two deer (Mazama americana) samples yielded two distinct 16S rRNA gene sequences, one identical to several sequences of Anaplasma bovis, and an unique sequence that grouped in a clade with different Anaplasma species. Our results indicate that a variety of genetically distinct Anaplasmataceae organisms, including potentially new Ehrlichia species, circulate under natural conditions in the Amazonian wildlife.

Sloths in the city: unexpectedly high density of pale-throated three-toed sloths (Bradypus tridactylus) found in an urban forest patch in Paramaribo, Suriname

Sloths in the city: unexpectedly high density of pale-throated three-toed sloths (Bradypus tridactylus) found in an urban forest patch in Paramaribo, Suriname

Predation attempt and abnormal coat coloration of the tayra (Eira barbara) in the Brazilian Central Amazon

ABSTRACTPredation is one of the most important interactions between species and a major selection pressure in wild mammal populations. Camouflage is a common pattern of colorations resulting from predation pressure, however, atypical coloration may appear in the wild. Both predation and atypical coloration in mammal species are difficult to observe in a natural setting but contain important biological information. Here we describe a leucistic tayra (Eira barbara) attempting to prey on a sloth (Bradypus tridactylus). The event occurred in Brazilian Central Amazon as a tayra unsuccessfully tried to kill an adult sloth in the mid-canopy of a secondary forest.

Morphology of the Dentin Structure of Sloths Bradypus tridactylus: A Light and Scanning Electron Microscopy Investigation

The aim of this study was to describe the dentine morphology of sloths (Bradypus tridactylus). The sloth teeth were removed and prepared for light microscopy (LM) and scanning electron microscopy analyses (SEM). LM revealed two patterns of tubular dentins: an outer with dentinary tubules over the all tooth length and one in the inner part with larger diameter and more spaced tubules, when compared to those present in the outer dentine. These findings were confirmed by SEM, which revealed a tubular pattern in the outer dentine like in humans. The inner dentine displayed pared grouped tubules that were characterized as vascular channels. It can be concluded that this sloth species present two types of dentins: an inner dentin (ortodentin) and an outer dentin characterized as a vascular dentin. This suggests a partial evolutive/adaptive process of this dental tissue, as compared to other mammalian species.

Use of Boat Surveys to Provide Complementary Data on the Ecology of Bradypus Tridactylus (Pilosa: Bradypodidae) from Northern Amazonia

Abstract Here we present new data on relative abundance and diet of Bradypus tridactylus Linnaeus, 1758 resulting from 2,505 km of river based surveys conducted in northern Amazonia. Our sampling effort using a motorized boat provided a low number of B. tridactylus detections (n = 4, relative abundance of 0.02 individuals/ 10 km surveyed). Our observations provide the first record of Parkia velutina Benoist (Leguminosae - Mimosoideae) consumption for B. tridactylus. We contribute with recommendations of standardized complementary survey techniques that can be used to provide data on relative abundance of arboreal mammals such as sloths in tropical forests.

Hatching Synchrony, Green Branch Collecting, and Prey Use by Nesting Harpy Eagles (Harpia harpyja)

Abstract We observed an occupied Harpy Eagle (Harpia harpyja) nest over three separate periods in eastern Venezuela. Both eggs in the clutch hatched on the same day, and two nestlings competed in the nest for 14 days before one succumbed. The female adult collected green branches 45 times over 60 days of observation. Green branch deliveries were positively associated with prey deliveries and our observations best support the ‘nest sanitation by covering prey’ hypothesis for the adaptive significance of green branch collecting. Prey delivery rate to the nest averaged one delivery every 2.4, 2.1, and 3.7 days in the three observation periods. Three-toed sloths (Bradypus tridactylus) and wedge-capped capuchins (Cebus olivaceus) were the most common prey items brought to the nest.

Reevaluation of the Geographical Distribution ofBradypus tridactylusLinnaeus, 1758 andB. variegatusSchinz, 1825

The confusing nomenclatural history of Bradypus tridactylus and B. variegatus has led to incorrect taxonomic attributions through time and, consequently, errors in range map inferences. In this note, we reevaluate the geographical distribution of B. tridactylus and B. variegatus based on museum specimens, field observations, and literature records of sloths. Our analyses revealed considerable range differences when compared to previous distribution inferences. For instance, B. tridactylus is restricted to the Guyana shield, and in Brazil it is only found north of the Amazon River and east of Negro River. Additional analysis using an Ecological Niche Modeling technique, and considering only bioclimatic and topographic variables, predicted that potential suitable areas for B. tridactylus are mostly limited by cold temperatures. However, when comparing our model to the present time distribution of forests we observed that the suitable area for B. tridactylus may be smaller than predicted by the model.

Bradypus tridactylus (Pilosa: Bradypodidae)

Bradypus tridactylus Linnaeus, 1758, is commonly called the pale-throated sloth. Males have a middorsal speculum. B. tridactylus is endemic to rain forests of northeastern South America. Like other sloths, B. tridactylus is a high-canopy folivore. It has a commensal relationship with the algae and invertebrates that live in its abundant pelage. It is listed as “Least Concern” by the International Union for Conservation of Nature and Natural Resources because of its distribution in pristine areas of the Amazon Basin. It does not adapt to zoo settings.

Intertooth Variation of Orthodentine Microwear in Armadillos (Cingulata) and Tree Sloths (Pilosa)

The analysis of orthodentine microwear has recently been established as a proxy for diet in extant and fossil xenarthrans (sloths, armadillos, and their extinct relatives). Previous analyses have relied on standardized comparison of sampling locations between taxa in order to statistically correlate microwear on xenarthran teeth with primary diet; variation in orthodentine microwear across the toothrow and its potential effect on dietary classification in xenarthrans remains unexplored. This study is the 1st to examine intertooth variation of microwear features in extant xenarthrans to test the necessity of standardized tooth comparison in orthodentine microwear analysis of paleodiet in fossil taxa. Statistical mean correlation tests were used to compare microwear variables between different sampling locations in a series of upper and lower teeth in 4 extant xenarthran species (Bradypus tridactylus [pale-throated three-toed sloth], Choloepus didactylus [Linnaeus' two-toed sloth], Dasypus novemcinctus [nine-banded armadillo], and Euphractus sexcinctus [six-banded armadillo]) and showed that microwear distribution between sampling locations is more conserved in three-toed sloths relative to two-toed sloths and armadillos. Significant variation in the latter groups may stem from uneven distribution of bite-force on the dentition in long-faced animals (two-toed sloths and armadillos) relative to short-faced animals (three-toed sloths), although food texture and intraspecific variation in diet may play a role as well. Based on results from extant taxa, standardized tooth comparison is required for analysis of paleodiet in glyptodonts and pampatheres and also is recommended for ground sloths in future studies of microwear.