Armadillo Species Research Articles

Canine iPSC generation with non-integrative vectors

Canine iPSC generation with non-integrative vectors

What do we know about armadillos? An analysis of four centuries of knowledge about a group of South American mammals, with emphasis on their conservation

Abstract Basic knowledge on the biology and ecology of a species is fundamental for the realistic assessment of its conservation status and for planning effective conservation strategies. The latest assessment of the 21 extant armadillo species (Xenarthra, Dasypodidae) by the International Union for Conservation of Nature (IUCN) for its Red List of Threatened Species shows that considerable gaps exist in our knowledge of these Neotropical mammals. Our goal was to analyse the existing literature on armadillos to define thematic and regional research priorities that will eventually benefit their conservation. We categorized 3117 publications on extant armadillos published between 1660 and 2011 according to their research topic, species studied, country and publication language. The number of publications per research topic and the number per species were very variable. The nine best‐studied species are classed as Least Concern by the IUCN, while three of the four least‐studied species are classed as Data Deficient. At least one field study was done in each range country, but over 80% of field research took place in the USA, Brazil, Argentina and Bolivia. Most research was done in the USA on leprosy in Dasypus novemcinctus. Most ecological research has been focused on four species, and data on the ecology of Data Deficient and Vulnerable taxa are virtually absent. Field research on armadillos should be intensified to broaden conservation‐relevant knowledge. Additional studies in the Guianas, Peru, Ecuador, Colombia, Venezuela and Paraguay are urgently needed to assess the conservation status of armadillos in these regions. Future research should focus on ecology, conservation, population genetics, reproduction and threats. Species priorities should include country endemics, such as Dasypus pilosus (Peru), Tolypeutes tricinctus (Brazil) and Dasypus yepesi and Chlamyphorus truncatus (Argentina), as well as other Data Deficient and Vulnerable species, especially Cabassous centralis and Calyptophractus retusus.

Effect of low-quality diet on torpor frequency and depth in the pichi Zaedyus pichiy (Xenarthra, Dasypodidae), a South American armadillo

Daily torpor is a physiological adaptation that allows mammals to cope with energetic challenges associated with unpredictable periods of food shortage. We experimentally tested whether food quality influences torpor frequency and depth in the pichi (Zaedyus pichiy), a small, opportunistically omnivorous armadillo endemic to arid and semi-arid habitats of southern South America. We recorded body temperature (Tsc) changes in 10 semi-captive, adult female pichis using dataloggers implanted subcutaneously during periods of 21 days. All individuals entered spontaneous daily torpor, but those receiving a low-quality diet had significantly lower daily mean and minimum Tsc, spent more time at Tsc below their individual lower limit of normothermia, and had a higher Heterothermy Index than controls. Five individuals entered prolonged torpor bouts lasting more than 24h, two of them repeatedly. Nine out of ten prolonged torpor bouts occurred in individuals feeding on a low-quality diet, suggesting that pichis are able to enter prolonged periods of torpor during severe environmental stress. In combination with their ability to hibernate and to respond to a reduced insect abundance by ingesting other food items, this physiological adaptation allows pichis to better cope with food shortages and a more extreme climate than other armadillos. It may explain why Z. pichiy naturally occurs farther south than any other armadillo species.

New Sylvatic Hosts of Trypanosoma cruzi and Their Reservoir Competence in the Humid Chaco of Argentina: A Longitudinal Study

A four-year longitudinal study of the structure of sylvatic transmission cycles of Trypanosoma cruzi, reservoir host competence and parasite discrete typing units was conducted in a disturbed rural area of the humid Chaco in Argentina. Among 190 mammals examined by xenodiagnosis and polymerase chain reaction amplification, the composite prevalence of infection was substantially higher in Dasypus novemcinctus armadillos (57.7%) and Didelphis albiventris opossums (38.1%) than in Euphractus sexcinctus (20.0%), Tolypeutes matacus (12.5%), and Chaetophractus vellerosus (6.3%) armadillos. Trypanosoma cruzi was detected for the first time in Thylamys pusilla small opossums and in two unidentified small rodents. Infection was spatially aggregated only in armadillos. All Didelphis were infected with T. cruzi I and all armadillo species were infected with T. cruzi III, implying two distinct sylvatic cycles with no inputs from the domestic cycle. Dasypus armadillos and Didelphis opossums were much more infectious to vectors than other armadillos, small opossums, or rodents.

Vascularización, morfología e histología del ovario en el armadillo Euphractus sexcinctus (Linnaeus, 1758)

SUMMARY Euphractus sexcinctus is a species of armadillo from South America and there are not many studies on its reproductive anatomy. Five corpses of adult females were collected according to the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA) guidelines. The ovaries were dissected and processed for histological examination after standard staining with hematoxylin-eosin. The shape of the ovaries was oval, measuring 7,9 mm in length and width 4,4 mm. There was no central concavity in the ovary as opossed to previous reports on armadillos. The ovaries were covered with simple squamous epithelium and connective tissue rich in collagen fibers. The cortical region presented follicles at various stages of development, with primordial follicles being in clusters. The region containing blood vessels and medullary interstitial cells, and sex cord as described in other species of armadillos. The tertiary follicle oocyte measured 183 ± 18 mm diameter, with a spherical nucleus and dispersed chromatin. The zona pellucida was homogeneous and acellular around the oocyte. Follicles with oocyte groups were not identified. This study demonstrated that ovarian morphology of E. sexcinctus was similar to that of other mammals, but different from other species of armadillos described in other articles.

Mycobacterium leprae in six-banded (Euphractus sexcinctus) and nine-banded armadillos (Dasypus novemcinctus) in Northeast Brazil

Human beings are the main reservoir of the causative agent of leprosy, Mycobacterium leprae. In the Americas, nine-banded armadillos (Dasypus novemcinctus) also act as a reservoir for the bacillus. In the state of Ceará (CE), which is located in Northeast Brazil and is an endemic area of leprosy, there are several species of armadillos, including D. novemcinctus and Euphractus sexcinctus (six-banded armadillo). Contact between humans and armadillos occur mainly through hunting, cleaning, preparing, cooking and eating. This study identified M. leprae DNA in the two main species of armadillos found in Northeast Brazil. A total of 29 wild armadillos (27 D. novemcinctus and 2 E. sexcinctus) were captured in different environments of CE countryside. Samples from the ear, nose, liver and spleen from each of these animals were tested by a nested M. leprae-specific repetitive element polymerase chain reaction assay. The samples that tested positive were confirmed by DNA sequencing. M. leprae was detected in 21% (6/29) of the animals, including five D. novemcinctus and one E. sexcinctus. This is the first Brazilian study to identify the presence of a biomarker of M. leprae in wild armadillos (D. novemcinctus and E. sexcinctus) in a leprosy hyperendemic area where there is continuous contact between humans and armadillos.

The sylvatic transmission cycle of Trypanosoma cruzi in a rural area in the humid Chaco of Argentina

Little is known about the sylvatic transmission cycle of Trypanosoma cruzi in the Gran Chaco ecoregion. We conducted surveys to identify the main sylvatic hosts of T. cruzi, parasite discrete typing units and vector species involved in Pampa del Indio, a rural area in the humid Argentinean Chaco. A total of 44 mammals from 14 species were captured and examined for infection by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR). Ten (22.7%) mammals were positive by xenodiagnosis or kDNA-PCR. Four of 11 (36%) Didelphis albiventris (white-eared opossums) and six of nine (67%) Dasypus novemcinctus (nine-banded armadillos) were positive by xenodiagnosis and or kDNA-PCR. Rodents, other armadillo species, felids, crab-eating raccoons, hares and rabbits were not infected. Positive animals were highly infectious to the bugs that fed upon them as determined by xenodiagnosis. All positive opossums were infected with T. cruzi I and all positive nine-banded armadillos with T. cruzi III. Extensive searches in sylvatic habitats using 718 Noireau trap-nights only yielded Triatoma sordida whereas no bug was collected in 26 light-trap nights. Four armadillos or opossums fitted with a spool-and-line device were successfully tracked to their refuges; only one Panstrongylus geniculatus was found in an armadillo burrow. No sylvatic triatomine was infected with T. cruzi by microscopical examination or kDNA-PCR. Our results indicate that two independent sylvatic transmission cycles of T. cruzi occur in the humid Chaco. The putative vectors of both cycles need to be identified conclusively.

The fetomaternal interface in the placenta of three species of armadillos (Eutheria, Xenarthra, Dasypodidae)

BackgroundPlacental characters vary among Xenarthra, one of four supraordinal clades of Eutheria. Armadillos are known for villous, haemochorial placentas similar to humans. Only the nine-banded armadillo has been well studied so far.MethodsPlacentas of three species of armadillos were investigated by means of histology, immunohistochemistry including proliferation marker, and transmission and scanning electron microscopy.ResultsThe gross anatomy differed: Euphractus sexcinctus and Chaetophractus villosus had extended, zonary placentas, whereas Chaetophractus vellerosus had a disk. All taxa had complex villous areas within the maternal blood sinuses of the endometrium. Immunohistochemistry indicated the validity of former interpretations that the endothelium of the sinuses was largely intact. Tips of the villi and the columns entering the maternal tissue possessed trophoblast cell clusters with proliferation activity. Elsewhere, the feto-maternal barrier was syncytial haemochorial with fetal vessels near the surface.ConclusionsDifferences among armadillos occurred in regard to the extension of the placenta, whereas the fine structure was similar. Parallels to the human suggest that armadillos are likely to be useful animal models for human placentation.

Characterizing adrenocortical activity in zoo-housed southern three-banded armadillos (Tolypeutes matacus)

Improving the husbandry in the southern three-banded armadillo (Tolypeutes matacus) through gaining knowledge of its stress physiology is imperative to maintaining a healthy, zoo-housed population. Our objectives were to: 1) validate the use of fecal hormone analysis for monitoring adrenocortical activity using both an adrenocorticotropic hormone (ACTH) challenge and biological events; and 2) characterize longitudinal adrenocortical activity in male and female southern three-banded armadillos. An ACTH injection was given intra-muscularly to one male (4IU/kg; 5.6IU total) and one female (5.5IU/kg; 8IU total) southern three-banded armadillo. Fecal samples were collected 1day pre- and continued 5days post-ACTH to capture the physiological response measured by elevated fecal glucocorticoid metabolites (FGM) to validate these techniques. Additionally, natural and routine events, including pairing individuals for breeding and veterinary procedures/handling, were used to biologically validate these techniques. To characterize adrenocortical activity, fecal samples (∼3025 total; n=275/animal/yr) were collected from 11 (5 males; 6 females) southern three-banded armadillos 5–7 times a week for 1year at Lincoln Park Zoo (Chicago, IL). A cortisol enzyme immunoassay was used for FGM analysis. The ACTH challenge in the male resulted in a twofold increase of FGM (1123.2±36.2ng/g dry feces) above baseline (675.7±10.0ng/g dry feces) at approximately 54–94h post- injection. The female exhibited a twofold increase (1635.4ng/g dry feces) over baseline FGMs (608.5±12.3ng/g dry feces) approximately 30h post-injection. Reproductive behaviors and veterinary procedures resulted in elevated FGM concentrations from all individuals except for one male. The longitudinal characterization demonstrated that sex and season did not influence (P<0.05) FGM concentrations. Individuals were highly variable with mean FGM concentration of 2010.1±862.4ng/g dry feces (range, 816.3–7889.1ng/g dry feces). Mean FGM baseline concentration was 878.5±201.8ng/g dry feces (range, 475.2–1955.5ng/g dry feces) with a mean elevated FGM concentrations of 2694.3±1111.4ng/g dry feces (range, 1110.3–10,683.3ng/g dry feces). This study provides the foundation for future research on how the environment directly affects the adrenocortical activity in this species of armadillo.

First Records of the Southern Naked-Tailed ArmadilloCabassous unicinctus(Cingulata: Dasypodidae) in Paraguay

Abstract The first specimens of southern naked-tailed armadillo Cabassous unicinctus squamicaudis from Paraguay are documented, extending the known distribution of the species approximately 270 km south-southwestward in the cerrado eco-region. This is the 12th species of armadillo documented as present in Paraguay. Paraguay is the only country with three representatives of the genus Cabassous occurring within its borders.

The 2009/2010 Armadillo Red List Assessment

The conservation status of the 21 extant armadillo species was re-assessed by specialists of the IUCN/SSC Anteater, Sloth and Armadillo Specialist Group between December 2009 and May 2010. Information on their geographic range, population size and status, habitat and ecology, threats, and existing conservation measures was collected from the literature and personal communications. Four armadillo species were classified as Vulnerable, four as Near Threatened, and four were categorized as Data Deficient. Less than half of all armadillo species were listed as Least Concern. Virtually all assessed species are affected by hunting as well as habitat fragmentation and degradation. The populations of only two species are thought to be increasing, while those of at least seven species are in decline. Much work is still needed to ensure the long-term survival of all species. Most armadillo species occur in at least one protected area, but other conservation actions are scarce.

Cuevas de Armadillos (Cingulata: Dasypodidae) en la Amazonía Central: Son Útiles para Identificar Especies?

Abstract Armadillo burrows are important structures for shelter and reproduction, and may be used as a source of information in ecological studies. In regions where several species coexist, it is necessary to know if the burrow measures are useful for species identification. We investigated whether burrow entrance morphometry is useful for differentiating four armadillo species in the central Amazon and evaluated whether entrance size was related to site topography. We registered entrance height and width, and entrance tunnel angle for each burrow encountered in 61 plots. We estimated the elevation and mean declination of the terrain at each burrow site. We measured the entrances of 188 armadillo burrows. Mean entrance height was 19.15 ± 5.04 cm and mean width 22.76 ± 5.85 cm. These variables were positively correlated and therefore not useful to distinguish individual species. Burrow size was not related to site topography. Burrows with similar dimensions may be built by species of similar size or by ind...

Contribuição ao Conhecimento da Distribuição Geográfica do Tatu-de-Rabo-Mole-GrandeCabassous tatouayno Brasil: Revisão, Status e Comentários sobre a Espécie

The greater naked-tailed armadillo Cabassous tatouay is one of the least-known armadillo species. Field records are rare, if not controversial, and only few specimens exist in scientific collections in Brazil. This species is listed in the Brazilian Red List of Threatened Species as well as in six official Brazilian state Red Lists. Fieldwork was performed between 2005 and 2008 to monitor wildlife in the central-western region of São Paulo State. Cabassous tatouay was registered in three opportunities, in the municipalities of Agudos, Borebi and Avaré, and ecological and morphometrical data were registered. Although this species tolerates altered habitats, the scarce field records may be related to its habits and have led to the lack of basic information on greater naked-tailed armadillos. This communication provides important ecological and biogeographical information about C. tatouay.

New Data on Armadillos (Xenarthra: Dasypodidae) for Central Patagonia, Argentina

Armadillos represent the most diverse family of xenarthrans. Although many studies have been done on these mammals, several topics, such as their local distribution, natural history, behavioral ecology and conservation, remain poorly known. Chaetophractus villosus and Zaedyus pichiy are the most common armadillos in extra-Andean Patagonia, a vast area in southern Argentina and Chile that encompasses different ecosystems and has been modified by human activities, mainly by sheep grazing. In this work we present new data on the distribution, natural history, conservation, and ecology of C. villosus and Z. pichiy from central Patagonia (Chubut and Río Negro provinces, Argentina). We registered 60 localities for C. villosus and 35 for Z. pichiy that confirm their presence in wide sectors of central Patagonia. Furthermore, we confirmed that these two armadillo species suffer high rates of mortality due to their use as a protein source, hunting by dogs, road traffic, and poisoning, among others. We conclude that their populations are at risk of overexploitation and local extinction. The basic knowledge provided here will be a first step towards the conservation of these characteristic Patagonian mammals.

Ecological differences between two sympatric species of armadillos (Xenarthra, Mammalia) in a temperate region of Argentina

Morpho-physiological specialization related to foraging can act as constraints on behaviour and ecological patterns of abundance and distribution. We tested this prediction in two species (weeping or screaming hairy armadillos Chaetophractus vellerosus Gray, 1865 and mulitas Dasypus hybridus Desmarest, 1804) that represent the two subfamilies of armadillos (Dasypodidae, Xenarthra): Euphractinae and Dasypodinae. The first subfamily possesses a well-developed masticatory apparatus that is considered primitive within the Xenarthra, while Dasypodinae show reductions in various aspects of cranial morphology. We sampled signs (burrows and foraging holes) and captured both species on 34 farms randomly selected in the north-eastern Pampas region of Argentina. We analyzed several niche dimensions. The two species showed significant differences in habitat use, seasonal patterns and diet. Weeping armadillos were generalists in their diet and active throughout the year. They were associated with calcareous-sand soil, as expected for a burrowing animal of the deserts. They tolerated a wide range of environmental conditions. We found that mulitas are myrmecophagous, and that they demonstrated a reduction in body temperature and activity during the cold season. As expected from their geographical distribution, mulitas used mainly vegetation with high cover and were associated with humic soils. Niche segregation between the two species of armadillos appeared to originate from different degrees of dietary specialization.

195 EVIDENCE OF SEASONALITY IN SEMEN CHARACTERISTICS OF CAPTIVE ANDEAN HAIRY ARMADILLO (CHAETOPHRACTUS NATIONI)

Chaetophractus nationi is an armadillo species that inhabits in the high Andes of Peru, Chile, and Bolivia at altitudes of over 3000 m. The main threats to this species are habitat loss and over-hunting; in the last 10 years it has been estimated that the population has declined by 30%. The species is categorized as Vulnerable (VU, A2d) by International Union for Conservation of Nature (IUCN) and Peruvian legislation (DS-034-2004-AG) and is listed in appendix II of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Chaetophractus nationi is 1 of 7 species of armadillos in which further studies on their reproductive biology and physiology are considered to be urgently needed. The aim of the present study was to determine the semen ejaculate values of C. nationi males in 2 opposite seasons. Six adult males of C. nationi belonging to the Huachipa Zoological Park (Lima, Peru) collection under the same captive conditions were used. Semen samples were collected coinciding with the Peruvian warm season (February) and cold season (June). The animals were chemically immobilized using ketamine (15 mg kg-1), xylazine (1 mg kg-1), and midazolam (0.4 mg kg-1) i.m. Semen was collected by an electroejaculation technique using commercial equipment (Eletrojet®, Eletrovet, São Paulo, Brazil) and a rectal probe specifically designed in Peru for the species. Progressive electrical stimulation from 2 to 6 V was applied in a protocol of 30 stimuli divided into 3 series: series 1, with 10 stimuli of 3 sec at 2 V; series 2, with 10 stimuli of 3 sec at 4 V; and series 3, with 10 stimuli of 3 sec at 6 V The results (mean ± SEM) for the warm season (26-28°C) were n = 6; volume = 80 ± 10.34 μL; pH = 8.2 ± 0.3; progressive motility = 77% ± 0.06; and sperm concentration/mL = 46.2 ± 2.9 × 106. The results (mean ± SEM) for the cold season (13-18°C) were n = 6; volume = 8.6 ± 2.27 μL; pH = 8.7 ± 0.18; and progressive motility = 80%. Sperm concentration could not be determined on the cold season samples because of the low volume collected. In summary, our results are suggestive of a seasonal pattern in semen characteristics of the Andean hairy armadillo that may be related to its reproductive activity in the wild. J. Pino and B. Shiga (UNMSM), for help with the rectal probe elaboration.

Eto-Ecología y Conservatión de Tres Especies de Armadillos (Dasypus hybridus, Chaetophractus villosusyC. vellerosus) en el Noreste de la Provincia de Buenos Aires, Argentina

Abstract A capture-recapture study was performed to obtain data on abundance of three armadillo species inhabiting a highly modified habitat—the Argentinean pampas—and the intrinsic factors affecting this parameter. A total of 144 live armadillos (42 Dasypus hybridus, 15 Chaetophractus villosus and 87 C. vellerosus) were caught and 49 dead animals (30 D. hybridus, 15 C. villosus and 4 C. vellerosus) were collected on four farms subjected to different degrees of land use. Armadillos were negatively affected by habitat use and hunting pressure. Densities varied between 0.07 and 0.6 armadillos per hectare, with higher densities occurring on farms farther away from urban settlements, with few domestic dogs, low hunting pressure, conservative land use, and well-preserved natural grasslands. The results suggest the existence of source-sink metapopulations.

Paleontology and Geochronology of the Deseadan (late Oligocene) of Moquegua, Perú

Subsequent to our initial reports of the discovery of Deseadan fossils in southern Perú, we have obtained new data regarding the paleontology and geology of the upper member of the Moquegua Formation. These data include newly recovered fossil specimens and further analyses of those collected in our earlier field seasons. We have also obtained an ash directly from within the fossil-bearing units near the summit of Cerro Pan de Azúcar. Biotites from this Sugarloaf ash give an age estimate of 26.25 ± 0.10 Ma, thus supporting our previous suggestion that these fossil-bearing horizons are of late Oligocene age (Deseadan South American Land Mammal “Age”) and removing our query regarding a possible early Miocene age. Most of the fossils are of notoungulates and most of these are trachytheriine mesotheriids. Remarkably, three distinct mesotheriid taxa appear to have been present in the Moquegua fauna, none of which are referable to the common Trachytherus alloxus of the nearby and at least partly contemporaneous Salla beds of Bolivia. Other fossils documented here include postcranial elements of the notohippid notoungulate, Moqueguahippus, a macraucheniid litoptern (cf. Coniopternium), an osteoderm of an unnamed species of armadillo (Dasypodidae, cf. Dasypodinae), and a claw of a phorusrhacid bird. We also describe a diminutive new hystricognath rodent, Sallamys quispea, sp. nov. It is similar to, but distinct from, S. pascuali of Salla. Indeed, despite the temporal and geographic proximity of Moquegua to Salla, none of the taxa from Moquegua that can be identified to species are known from Salla. Likewise, we have failed to find any dasypodids from Salla that have osteoderms like that described in this work. Thus, it is appears that distinctive paleogeographic and paleoenvironmental conditions in the late Oligocene led to a regional biotic differentiation for the Moquegua area of coastal Perú.

Health Assessment of Free-Ranging Three-Banded (Tolypeutes matacus) and Nine-Banded (Dasypus novemcinctus) Armadillos in the Gran Chaco, Bolivia

The Gran Chaco, Bolivia, has a total of seven species of armadillos with the three-banded (Tolypeutes matacus) and nine-banded (Dasypus novemcinctus) the most commonly hunted by the local Isoseño-Guarani people. Armadillos are known carriers of zoonotic pathogens, including Mycobacterium leprae, Toxoplasma gondii, and Trypanosoma cruzi; thus human handling and consumption of these species may have a significant public health impact. A health assessment that included physical examinations, hematology, plasma biochemical analyses, levels of exposure to selected infectious agents, and endoparasite and ectoparasite identification was performed on nine-banded and three-banded armadillos in the Gran Chaco, Bolivia. Based on clinical findings, the general health of these armadillos was rated as good. However, many of the nine-banded armadillos (64%) had abrasions and wounds, probably related to the capture method. The blood value results from a subset of these armadillos are presented as baseline values for free-ranging populations of both these species in Bolivia. Serologic antibody tests for M. leprae were negative in three-banded (n = 8) and nine-banded (n = 2) armadillos. Three-banded armadillos were antibody positive for Eastern equine encephalitis virus (8/8; 100%) and Saint Louis encephalitis virus (5/8; 62.5%). Two of 12 (16.7%) three-banded armadillos tested were antigen positive for Dirofilaria immitis. Nine-banded armadillos were antibody positive for T. gondii (3/9; 33.3%), Eastern equine encephalitis virus (5/8; 62.5%), and T. cruzi (2/9; 22.2%). Two of eight (25%) nine-banded armadillos were antigen positive for D. immitis. A number of endo- and ectoparasites were identified in/on both species of armadillos. Results from this study support the possibility that the handling and consumption of these species by the local Isoseño-Guarani people may have a public health impact.

A 3D geometric morphometric analysis of digging ability in the extant and fossil cingulate humerus

AbstractDigging ability in armadillos has been shown to be closely related to the relative length of the olecranon process of the ulna. This study uses geometric morphometrics to examine the relationship between humeral shape, digging ability and size in a range of living and fossil cingulates. The extant species in the sample include representatives of 11 species of armadillo, while the fossil specimens include three species of fossil armadillos (Peltephilus, Proeutatus and Eutatus) and three Glyptodonts (Propalaeohoplophorus, Glyptodon and Neosclerocalyptus). The results show that in general, living species with good digging ability have larger sites for muscle attachment, particularly the proximal tubercles and the crests descending therefrom, and the epicondylar region at the distal end of the humerus. Some differences were found in the smallest armadillo (Chlamyphorus truncatus), which seems to have a different method of digging. The proportions of the olecranon process would indicate good digging ability in some glyptodonts, but humeral features do not fit with this interpretation and the differences may be related to large size. The relationship between cingulate phylogeny and humeral morphology is also examined, and it seems that while cingulates are to some extent constrained by their phylogeny, many of the humeral features are directly related to digging.