Historic Sampling of a Vanishing Beast: Population Structure and Diversity in the Black Rhinoceros.

The black rhinoceros (Diceros bicornis L.) is a critically endangered species historically distributed across sub-Saharan Africa. Hunting and habitat disturbance have diminished both its numbers and distribution since the 19th century, but a poaching crisis in the late 20th century drove them to the brink of extinction. Genetic and genomic assessments can greatly increase our knowledge of the species and inform management strategies. However, when a species has been severely reduced, with the extirpation and artificial admixture of several populations, it is extremely challenging to obtain an accurate understanding of historic population structure and evolutionary history from extant samples. Therefore, we generated and analyzed whole genomes from 63 black rhinoceros museum specimens collected between 1775 and 1981. Results showed that the black rhinoceros could be genetically structured into six major historic populations (Central Africa, East Africa, Northwestern Africa, Northeastern Africa, Ruvuma, and Southern Africa) within which were nested four further subpopulations (Maasailand, southwestern, eastern rift, and northern rift), largely mirroring geography, with a punctuated north-south cline. However, we detected varying degrees of admixture among groups and found that several geographical barriers, most prominently the Zambezi River, drove population discontinuities. Genomic diversity was high in the middle of the range and decayed toward the periphery. This comprehensive historic portrait also allowed us to ascertain the ancestry of 20 resequenced genomes from extant populations. Lastly, using insights gained from this unique temporal data set, we suggest management strategies, some of which require urgent implementation, for the conservation of the remaining black rhinoceros diversity.

Blue Turns to Gray: Paleogenomic Insights into the Evolutionary History and Extinction of the Blue Antelope (Hippotragus leucophaeus).

The blue antelope (Hippotragus leucophaeus) is the only large African mammal species to have become extinct in historical times, yet no nuclear genomic information is available for this species. A recent study showed that many alleged blue antelope museum specimens are either roan (Hippotragus equinus) or sable (Hippotragus niger) antelopes, further reducing the possibilities for obtaining genomic information for this extinct species. While the blue antelope has a rich fossil record from South Africa, climatic conditions in the region are generally unfavorable to the preservation of ancient DNA. Nevertheless, we recovered two blue antelope draft genomes, one at 3.4× mean coverage from a historical specimen (∼200 years old) and one at 2.1× mean coverage from a fossil specimen dating to 9,800-9,300 cal years BP, making it currently the oldest paleogenome from Africa. Phylogenomic analyses show that blue and sable antelope are sister species, confirming previous mitogenomic results, and demonstrate ancient gene flow from roan into blue antelope. We show that blue antelope genomic diversity was much lower than in roan and sable antelope, indicative of a low population size since at least the early Holocene. This supports observations from the fossil record documenting major decreases in the abundance of blue antelope after the Pleistocene-Holocene transition. Finally, the persistence of this species throughout the Holocene despite low population size suggests that colonial-era human impact was likely the decisive factor in the blue antelope's extinction.

Abnormal (Hydroxy)proline Deuterium Content Redefines Hydrogen Chemical Mass.

Analyzing the δ2H values in individual amino acids of proteins extracted from vertebrates, we unexpectedly found in some samples, notably bone collagen from seals, more than twice as much deuterium in proline and hydroxyproline residues than in seawater. This corresponds to at least 4 times higher δ2H than in any previously reported biogenic sample. We ruled out diet as a plausible mechanism for such anomalous enrichment. This finding puts into question the old adage that "you are what you eat".

Historical population declines prompted significant genomic erosion in the northern and southern white rhinoceros (Ceratotherium simum).

Large vertebrates are extremely sensitive to anthropogenic pressure, and their populations are declining fast. The white rhinoceros (Ceratotherium simum) is a paradigmatic case: this African megaherbivore has suffered a remarkable decline in the last 150 years due to human activities. Its subspecies, the northern (NWR) and the southern white rhinoceros (SWR), however, underwent opposite fates: the NWR vanished quickly, while the SWR recovered after the severe decline. Such demographic events are predicted to have an erosive effect at the genomic level, linked to the extirpation of diversity, and increased genetic drift and inbreeding. However, there is little empirical data available to directly reconstruct the subtleties of such processes in light of distinct demographic histories. Therefore, we generated a whole-genome, temporal data set consisting of 52 resequenced white rhinoceros genomes, representing both subspecies at two time windows: before and during/after the bottleneck. Our data reveal previously unknown population structure within both subspecies, as well as quantifiable genomic erosion. Genome-wide heterozygosity decreased significantly by 10% in the NWR and 36% in the SWR, and inbreeding coefficients rose significantly by 11% and 39%, respectively. Despite the remarkable loss of genomic diversity and recent inbreeding it suffered, the only surviving subspecies, the SWR, does not show a significant accumulation of genetic load compared to its historical counterpart. Our data provide empirical support for predictions about the genomic consequences of shrinking populations, and our findings have the potential to inform the conservation efforts of the remaining white rhinoceroses.

Synchronous genetic turnovers across Western Eurasia in Late Pleistocene collared lemmings.

Recent palaeogenetic studies indicate a highly dynamic history in collared lemmings (Dicrostonyx spp.), with several demographical changes linked to climatic fluctuations that took place during the last glaciation. At the western range margin of D. torquatus, these changes were characterized by a series of local extinctions and recolonizations. However, it is unclear whether this pattern represents a local phenomenon, possibly driven by ecological edge effects, or a global phenomenon that took place across large geographical scales. To address this, we explored the palaeogenetic history of the collared lemming using a next-generation sequencing approach for pooled mitochondrial DNA amplicons. Sequences were obtained from over 300 fossil remains sampled across Eurasia and two sites in North America. We identified five mitochondrial lineages of D. torquatus that succeeded each other through time across Europe and western Russia, indicating a history of repeated population extinctions and recolonizations, most likely from eastern Russia, during the last 50 000 years. The observation of repeated extinctions across such a vast geographical range indicates large-scale changes in the steppe-tundra environment in western Eurasia during the last glaciation. All Holocene samples, from across the species' entire range, belonged to only one of the five mitochondrial lineages. Thus, extant D. torquatus populations only harbour a small fraction of the total genetic diversity that existed across different stages of the Late Pleistocene. In North American samples, haplotypes belonging to both D. groenlandicus and D. richardsoni were recovered from a Late Pleistocene site in south-western Canada. This suggests that D. groenlandicus had a more southern and D. richardsoni a more northern glacial distribution than previously thought. This study provides significant insights into the population dynamics of a small mammal at a large geographical scale and reveals a rather complex demographical history, which could have had bottom-up effects in the Late Pleistocene steppe-tundra ecosystem.

The evolutionary origin and population history of the grauer gorilla.

Gorillas living in western central Africa (Gorilla gorilla) are morphologically and genetically distinguishable from those living in eastern central Africa (Gorilla beringei). Genomic analyses show eastern gorillas experienced a significant reduction in population size during the Pleistocene subsequent to geographical isolation from their western counterparts. However, how these results relate more specifically to the recent biogeographical and evolutionary history of eastern gorillas remains poorly understood. Here we show that two rare morphological traits are present in the hands and feet of both eastern gorilla subspecies at strikingly high frequencies (>60% in G. b. graueri; ∼28% in G. b. beringei) in comparison with western gorillas (<1%). The intrageneric distribution of these rare traits suggests that they became common among eastern gorillas after diverging from their western relatives during the early to middle Pleistocene. The extremely high frequencies observed among grauer gorillas-which currently occupy a geographic range more than ten times the size of that of mountain gorillas-imply that grauers originated relatively recently from a small founding population of eastern gorillas. Current paleoenvironmental, geological, and biogeographical evidence supports the hypothesis that a small group of eastern gorillas likely dispersed westward from the Virungas into present-day grauer range in the highlands just north of Lake Kivu, either immediately before or directly after the Younger Dryas interval. We propose that as the lowland forests of central Africa expanded rapidly during the early Holocene, they became connected with the expanding highland forests along the Albertine Rift and enabled the descendants of this small group to widely disperse. The descendant populations significantly expanded their geographic range and population numbers relative to the gorillas of the Virunga Mountains and the Bwindi-Impenetrable Forest, ultimately resulting in the grauer gorilla subspecies recognized today. This founder-effect hypothesis offers some optimism for modern conservation efforts to save critically endangered eastern gorillas from extinction.

On the origin of the Norwegian lemming.

The Pleistocene glacial cycles resulted in significant changes in species distributions, and it has been discussed whether this caused increased rates of population divergence and speciation. One species that is likely to have evolved during the Pleistocene is the Norwegian lemming (Lemmus lemmus). However, the origin of this species, both in terms of when and from what ancestral taxon it evolved, has been difficult to ascertain. Here, we use ancient DNA recovered from lemming remains from a series of Late Pleistocene and Holocene sites to explore the species' evolutionary history. The results revealed considerable genetic differentiation between glacial and contemporary samples. Moreover, the analyses provided strong support for a divergence time prior to the Last Glacial Maximum (LGM), therefore likely ruling out a postglacial colonization of Scandinavia. Consequently, it appears that the Norwegian lemming evolved from a small population that survived the LGM in an ice-free Scandinavian refugium.

Colonial-driven extinction of the blue antelope despite genomic adaptation to low population size.

Low genomic diversity is generally indicative of small population size and is considered detrimental by decreasing long-term adaptability.1,2,3,4,5,6 Moreover, small population size may promote gene flow with congeners and outbreeding depression.7,8,9,10,11,12,13 Here, we examine the connection between habitat availability, effective population size (Ne), and extinction by generating a 40× nuclear genome from the extinct blue antelope (Hippotragus leucophaeus). Historically endemic to the relatively small Cape Floristic Region in southernmost Africa,14,15 populations were thought to have expanded and contracted across glacial-interglacial cycles, tracking suitable habitat.16,17,18 However, we found long-term low Ne, unaffected by glacial cycles, suggesting persistence with low genomic diversity for many millennia prior to extinction in ∼AD 1800. A lack of inbreeding, alongside high levels of genetic purging, suggests adaptation to this long-term low Ne and that human impacts during the colonial era (e.g., hunting and landscape transformation), rather than longer-term ecological processes, were central to its extinction. Phylogenomic analyses uncovered gene flow between roan (H. equinus) and blue antelope, as well as between roan and sable antelope (H. niger), approximately at the time of divergence of blue and sable antelope (∼1.9 Ma). Finally, we identified the LYST and ASIP genes as candidates for the eponymous bluish pelt color of the blue antelope. Our results revise numerous aspects of our understanding of the interplay between genomic diversity and evolutionary history and provide the resources for uncovering the genetic basis of this extinct species' unique traits.

Fur glowing under ultraviolet: in situ analysis of porphyrin accumulation in the skin appendages of mammals.

Examples of photoluminescence (PL) are being reported with increasing frequency in a wide range of organisms from diverse ecosystems. However, the chemical basis of this PL remains poorly defined, and our understanding of its potential ecological function is still superficial. Among mammals, recent analyses have identified free-base porphyrins as the compounds responsible for the reddish ultraviolet-induced photoluminescence (UV-PL) observed in the pelage of springhares and hedgehogs. However, the localization of the pigments within the hair largely remains to be determined. Here, we use photoluminescence multispectral imaging emission and excitation spectroscopy to detect, map, and characterize porphyrinic compounds in skin appendages in situ. We also document new cases of mammalian UV-PL caused by free-base porphyrins in distantly related species. Spatial distribution of the UV-PL is strongly suggestive of an endogenous origin of the porphyrinic compounds. We argue that reddish UV-PL is predominantly observed in crepuscular and nocturnal mammals because porphyrins are photodegradable. Consequently, this phenomenon may not have a specific function in intra- or interspecific communication but rather represents a byproduct of potentially widespread physiological processes.

Assessing the Taxonomic Status of the Gray Brocket Mazama simplicicornis argentina Lönnberg, 1919 (Artiodactyla: Cervidae).

Mazama simplicicornis argentina is the name that was given to describe a gray brocket collected by Lönberg in 1919 in the central Chaco region of Argentina. Subsequent authors, based on morphological similarities, considered this name to be a synonym for the species Subulo gouazoubira Fischer, 1814 from Paraguay. In the absence of genetic analyses to compare the Argentinian and Paraguayan gray brockets, we aimed to clarify the taxonomy of M. simplicicornis argentina through an integrative assessment using morphological, cytogenetical, and molecular data from its holotype and a current topotype. Qualitative skull features and cranio-morphometric results of M. simplicicornis argentina showed a great similarity with the S. gouazoubira neotype characters. The diploid chromosome number of M. simplicicornis argentina topotype corresponded with the karyotypical pattern of S. gouazoubira with 2n = 70 and FN = 70, showing a great similarity in all classic and molecular cytogenetic results and revealing the homologies between karyotypes. The phylogenetic analysis of mitochondrial genes used in this study (concatenated partial ND5 and Cytb gene) allocated the M. simplicicornis argentina specimens in the monophyletic clade of S. gouazoubira with a branch value of 100%. These results show that there is no discontinuity between the Argentinian and Paraguayan gray brockets. Therefore, the individuals originally described as M. simplicicornis argentina should be recognized as S. gouazoubira.

Genome sequencing of 2000 canids by the Dog10K consortium advances the understanding of demography, genome function and architecture.

BACKGROUND: The international Dog10K project aims to sequence and analyze several thousand canine genomes. Incorporating 20 × data from 1987 individuals, including 1611 dogs (321 breeds), 309 village dogs, 63 wolves, and four coyotes, we identify genomic variation across the canid family, setting the stage for detailed studies of domestication, behavior, morphology, disease susceptibility, and genome architecture and function. RESULTS: We report the analysis of > 48 M single-nucleotide, indel, and structural variants spanning the autosomes, X chromosome, and mitochondria. We discover more than 75% of variation for 239 sampled breeds. Allele sharing analysis indicates that 94.9% of breeds form monophyletic clusters and 25 major clades. German Shepherd Dogs and related breeds show the highest allele sharing with independent breeds from multiple clades. On average, each breed dog differs from the UU_Cfam_GSD_1.0 reference at 26,960 deletions and 14,034 insertions greater than 50 bp, with wolves having 14% more variants. Discovered variants include retrogene insertions from 926 parent genes. To aid functional prioritization, single-nucleotide variants were annotated with SnpEff and Zoonomia phyloP constraint scores. Constrained positions were negatively correlated with allele frequency. Finally, the utility of the Dog10K data as an imputation reference panel is assessed, generating high-confidence calls across varied genotyping platform densities including for breeds not included in the Dog10K collection. CONCLUSIONS: We have developed a dense dataset of 1987 sequenced canids that reveals patterns of allele sharing, identifies likely functional variants, informs breed structure, and enables accurate imputation. Dog10K data are publicly available.

Biomechanical adaptations for burrowing in the incisor enamel microstructure of Geomyidae and Heteromyidae (Rodentia: Geomyoidea).

The enamel microstructure of fossil and extant Geomyoidea (Geomyidae, Heteromyidae) lower incisors incorporates three- or two-layered schmelzmusters with uniserial, transverse Hunter-Schreger bands having parallel and perpendicular or exclusively perpendicular oriented interprismatic matrix. Phylogenetically, these schmelzmusters are regarded as moderately (enamel type 2) to highly derived (enamel type 3). Our analysis detected a zone of modified radial enamel close to the enamel-dentine junction. Modified radial enamel shows a strong phylogenetic signal within the clade Geomorpha as it is restricted to fossil and extant Geomyoidea and absent in Heliscomyidae, Florentiamyidae, and Eomyidae. This character dates back to at least the early Oligocene (early Arikareean, 29 Ma), where it occurs in entoptychine gophers. We contend that this specialized incisor enamel architecture developed as a biomechanical adaptation to regular burrowing activities including chisel-tooth digging and a fiber-rich diet and was probably present in the common ancestor of the clade. We regard the occurrence of modified radial enamel in lower incisors of scratch-digging Geomyidae and Heteromyidae as the retention of a plesiomorphic character that is selectively neutral. The shared occurrence of modified radial enamel is a strong, genetically anchored argument for the close phylogenetic relationship of Geomyidae and Heteromyidae on the dental microstructure level.

The oral microbiota of wild bears in Sweden reflects the history of antibiotic use by humans.

Following the advent of industrial-scale antibiotic production in the 1940s,1 antimicrobial resistance (AMR) has been on the rise and now poses a major global health threat in terms of mortality, morbidity, and economic burden.2,3 Because AMR can be exchanged between humans, livestock, and wildlife, wild animals can be used as indicators of human-associated AMR contamination of the environment.4 However, AMR is a normal function of natural environments and is present in host-associated microbiomes, which makes it challenging to distinguish between anthropogenic and natural sources.4,5 One way to overcome this difficulty is to use historical samples that span the period from before the mass production of antibiotics to today. We used shotgun metagenomic sequencing of dental calculus, the calcified form of the oral microbial biofilm, to determine the abundance and repertoire of AMR genes in the oral microbiome of Swedish brown bears collected over the last 180 years. Our temporal metagenomics approach allowed us to establish a baseline of natural AMR in the pre-antibiotics era and to quantify a significant increase in total AMR load and diversity of AMR genes that is consistent with patterns of national human antibiotic use. We also demonstrated a significant decrease in total AMR load in bears in the last two decades, which coincides with Swedish strategies to mitigate AMR. Our study suggests that public health policies can be effective in limiting human-associated AMR contamination of the environment and wildlife.

Identifying the true number of specimens of the extinct blue antelope (Hippotragus leucophaeus).

Native to southern Africa, the blue antelope (Hippotragus leucophaeus) is the only large African mammal species known to have become extinct in historical times. However, it was poorly documented prior to its extinction ~ 1800 AD, and many of the small number of museum specimens attributed to it are taxonomically contentious. This places limitations on our understanding of its morphology, ecology, and the mechanisms responsible for its demise. We retrieved genetic information from ten of the sixteen putative blue antelope museum specimens using both shotgun sequencing and mitochondrial genome target capture in an attempt to resolve the uncertainty surrounding the identification of these specimens. We found that only four of the ten investigated specimens, and not a single skull, represent the blue antelope. This indicates that the true number of historical museum specimens of the blue antelope is even smaller than previously thought, and therefore hardly any reference material is available for morphometric, comparative and genetic studies. Our study highlights how genetics can be used to identify rare species in natural history collections where other methods may fail or when records are scarce. Additionally, we present an improved mitochondrial reference genome for the blue antelope as well as one complete and two partial mitochondrial genomes. A first analysis of these mitochondrial genomes indicates low levels of maternal genetic diversity in the 'museum population', possibly confirming previous results that blue antelope population size was already low at the time of the European colonization of South Africa.

Complementary approaches to tooth wear analysis in Tritylodontidae (Synapsida, Mammaliamorpha) reveal a generalist diet.

Stereoscopic microwear and 3D surface texture analyses on the cheek teeth of ten Upper Triassic to Lower Cretaceous tritylodontid (Mammaliamorpha) taxa of small/medium to large body size suggest that all were generalist feeders and none was a dietary specialist adapted to herbivory. There was no correspondence between body size and food choice. Stereomicroscopic microwear analysis revealed predominantly fine wear features with numerous small pits and less abundant fine scratches as principal components. Almost all analyzed facets bear some coarser microwear features, such as coarse scratches, large pits, puncture pits and gouges pointing to episodic feeding on harder food items or exogenous effects (contamination of food with soil grit and/or dust), or both. 3D surface texture analysis indicates predominantly fine features with large void volume, low peak densities, and various stages of roundness of the peaks. We interpret these features to indicate consumption of food items with low to moderate intrinsic abrasiveness and can exclude regular rooting, digging or caching behavior. Possible food items include plant vegetative parts, plant reproductive structures (seeds and seed-bearing organs), and invertebrates (i.e., insects). Although the tritylodontid tooth morphology and auto-occlusion suggest plants as the primary food resource, our results imply a wider dietary range including animal matter.

Feeding Ecology in Oligocene Mylodontoid Sloths (Mammalia, Xenarthra) as Revealed by Orthodentine Microwear Analysis.

Recently, dental microwear analysis has been successfully employed to xenarthran teeth. Here, we present new data on use wear features on 16 molariforms of Orophodon hapaloides and Octodontotherium grande. These taxa count among the earliest sloths and are known from the Deseadan SALMA (late Oligocene). Modern phylogenetic analyses classify Octodontotherium and Orophodon within Mylodontoidea with whom they share lobate cheek teeth with an outer layer of cementum and a thick layer of orthodentine. Similar target areas of 100µm2 were analyzed on the orthodentine surface of each tooth by stereomicroscopic microwear and by SEM microwear. Results were unlike those of extant sloths (stereomicroscopic microwear: Bradypus, Choloepus) and published data from fossil sloths (SEM microwear: Acratocnus, Megalonyx, Megatherium, Thinobadistes); thus, both approaches independently indicate a different feeding ecology for the Oligocene taxa. The unique microwear results suggest that both taxa fed on plant material with low to moderate intrinsic toughness (foliage, twigs) but also proposes intake of tougher food items (e.g., seeds). Frequent gouging of the tooth surfaces can be explained by exogenous influence on microwear, such as possible intake of abrasive grit. We suggest an unspecialized herbivorous diet for Octodontotherium and Orophodon utilizing diverse food resources of their habitat. These interpretations support the reconstruction of (1) Deseadan environments as open habitats with spreading savannas/grasslands and (2) both taxa as wide-muzzled bulk feeders at ground level.

Significant loss of mitochondrial diversity within the last century due to extinction of peripheral populations in eastern gorillas.

Species and populations are disappearing at an alarming rate as a direct result of human activities. Loss of genetic diversity associated with population decline directly impacts species' long-term survival. Therefore, preserving genetic diversity is of considerable conservation importance. However, to assist in conservation efforts, it is important to understand how genetic diversity is spatially distributed and how it changes due to anthropogenic pressures. In this study, we use historical museum and modern faecal samples of two critically endangered eastern gorilla taxa, Grauer's (Gorilla beringei graueri) and mountain gorillas (Gorilla beringei beringei), to directly infer temporal changes in genetic diversity within the last century. Using over 100 complete mitochondrial genomes, we observe a significant decline in haplotype and nucleotide diversity in Grauer's gorillas. By including historical samples from now extinct populations we show that this decline can be attributed to the loss of peripheral populations rather than a decrease in genetic diversity within the core range of the species. By directly quantifying genetic changes in the recent past, our study shows that human activities have severely impacted eastern gorilla genetic diversity within only four to five generations. This rapid loss calls for dedicated conservation actions, which should include preservation of the remaining peripheral populations.

Extinctions, genetic erosion and conservation options for the black rhinoceros (Diceros bicornis).

The black rhinoceros is again on the verge of extinction due to unsustainable poaching in its native range. Despite a wide historic distribution, the black rhinoceros was traditionally thought of as depauperate in genetic variation, and with very little known about its evolutionary history. This knowledge gap has hampered conservation efforts because hunting has dramatically reduced the species' once continuous distribution, leaving five surviving gene pools of unknown genetic affinity. Here we examined the range-wide genetic structure of historic and modern populations using the largest and most geographically representative sample of black rhinoceroses ever assembled. Using both mitochondrial and nuclear datasets, we described a staggering loss of 69% of the species' mitochondrial genetic variation, including the most ancestral lineages that are now absent from modern populations. Genetically unique populations in countries such as Nigeria, Cameroon, Chad, Eritrea, Ethiopia, Somalia, Mozambique, Malawi and Angola no longer exist. We found that the historic range of the West African subspecies (D. b. longipes), declared extinct in 2011, extends into southern Kenya, where a handful of individuals survive in the Masai Mara. We also identify conservation units that will help maintain evolutionary potential. Our results suggest a complete re-evaluation of current conservation management paradigms for the black rhinoceros.

Do extant elephants have superior canal dehiscence syndrome?

CONCLUSION: X-ray CT of an Asian elephant's skull suggest that elephants do not have a labyrinthine 3(rd) mobile window. This excludes the concept that elephants benefit from enhancement of bone conducted vibration by an extra opening of the labyrinth. This finding does not, however, exclude that elephants use bone conducted hearing for seismic detection, nor that other species may use an extra labyrinthine opening for improved detection of seismic signals. OBJECTIVES: In man, a pathologic extra opening of the bony labyrinth causes altered hearing with supranormal bone conduction. Theoretically, this variation in auditory performance could be advantageous for detection of seismic waves. METHOD: The skull of an adult Asian elephant was examined by X-ray computed tomography to investigate whether a natural '3(rd) mobile window' mechanism for enhanced sensitivity of body sounds exist in elephants. RESULTS: Although the entire elephant's skull was otherwise broadly aerated, the labyrinth areas were surrounded by dense bone.

Osteoderm histology of the Pampatheriidae (Cingulata, Xenarthra, Mammalia): Implications for systematics, osteoderm growth, and biomechanical adaptation.

Pampatheres are extinct, large-bodied cingulates, which share morphological characters with both armadillos and glyptodonts but are considered to be more closely related to the latter. The osteoderm histology of six pampathere taxa was examined and compared to the histology of other cingulate osteoderms. This study investigates the development and functional adaptation of pampathere osteoderms as well as the phylogenetic relationships of the Pampatheriidae within the Cingulata. We found that pampathere osteoderms share a uniform histological organization based on a basic diploe-like structure. After initial stages of intramembranous growth, metaplastic ossification, that is, the direct incorporation and mineralization of pre-existing protein fibers, plays an important role in osteoderm development and provides information on various kinds of soft tissue otherwise not preserved. The latest stages of osteoderm growth are dominated by periosteal bone formation especially in the superficial cortex. Movable band osteoderms show regular arrangements of incorporated fibers that may increase the resistance of particularly weak areas against strain. The histological composition of pampathere osteoderms is plesiomorphic in its basic structure but shows a number of derived features. A unique array of Sharpey's fibers that are incorporated into the bone matrix at sutured osteoderm margins is interpreted as a synapomorphy of pampatheres. The arrangement of dermal fibers in the deep and superficial cortexes supports the close relationship between pampatheres and glyptodonts.