Natural Trap Cave Research Articles

Lipid biomarkers provide evolutionary signposts for the oldest known cases of tuberculosis

Studies on the evolution of tuberculosis, and the influence of this disease on human and animal development and interaction, require the accumulation of indisputable biomarker evidence. Ideally, the determination of full genomes would provide all the necessary information, but for very old specimens DNA preservation may be compromised and only limited DNA amplification may be a possibility. Mycobacterium tuberculosis is characterised by the presence of unusual cell envelope lipids, with specific biomarker potential. Lipid biomarker recognition has been decisive in pinpointing the oldest known cases of human and animal tuberculosis; the former are a woman and child from a pre-pottery settlement at Atlit-Yam, Israel (∼9,000 ka) and the latter is an extinct Bison antiquus from Natural Trap Cave, Wyoming (∼17,000 ka). Including some new data, it is demonstrated how analysis of a combination of mycolic, mycocerosic and mycolipenic acid and phthiocerol biomarkers provide incontrovertible evidence for tuberculosis in these landmark specimens.

Comparison of fluoride and direct AMS radiocarbon dating of black bear bone from Lawson Cave, Missouri

After a 20-year hiatus (1955–1975) during which few archaeologists discussed fluoride dating, the method again received attention in the 1980s and 1990s when some argued for its validity. As a dating method, fluoride dating depends on the rate at which fluorine ions replace hydroxyl ions in osseous tissue. The rate of replacement is influenced by the properties of the skeletal part (SP), sediment chemistry (K), and sediment hydrology (H), and the replacement rate influences estimates of time. Calibrated AMS radiocarbon assays of 10 black bear (Ursus americanus) femora from a natural-trap cave in central Missouri are weakly correlated with fluorine concentrations, determined by neutron activation analysis in the 10 femora. Despite minimal variation in SP, K, and H, results indicate fluoride dating can be considered a valid dating method only in cases when the chronological validity of its results are confirmed with independent chronometric data. As similarities in fluorine amounts across specimens increase, provenience information and bone orientation data as well as fine resolution data on K and H become critical to the application of fluoride dating.

Mycobacterium tuberculosis Complex Lipid Virulence Factors Preserved in the 17,000-Year-Old Skeleton of an Extinct Bison, Bison antiquus

Tracing the evolution of ancient diseases depends on the availability and accessibility of suitable biomarkers in archaeological specimens. DNA is potentially information-rich but it depends on a favourable environment for preservation. In the case of the major mycobacterial pathogens, Mycobacterium tuberculosis and Mycobacterium leprae, robust lipid biomarkers are established as alternatives or complements to DNA analyses. A DNA report, a decade ago, suggested that a 17,000-year-old skeleton of extinct Bison antiquus, from Natural Trap Cave, Wyoming, was the oldest known case of tuberculosis. In the current study, key mycobacterial lipid virulence factor biomarkers were detected in the same two samples from this bison. Fluorescence high-performance liquid chromatography (HPLC) indicated the presence of mycolic acids of the mycobacterial type, but they were degraded and could not be precisely correlated with tuberculosis. However, pristine profiles of C29, C30 and C32 mycocerosates and C27 mycolipenates, typical of the Mycobacterium tuberculosis complex, were recorded by negative ion chemical ionization gas chromatography mass spectrometry of pentafluorobenzyl ester derivatives. These findings were supported by the detection of C34 and C36 phthiocerols, which are usually esterified to the mycocerosates. The existence of Pleistocene tuberculosis in the Americas is confirmed and there are many even older animal bones with well-characterised tuberculous lesions similar to those on the analysed sample. In the absence of any evidence of tuberculosis in human skeletons older than 9,000 years BP, the hypothesis that this disease evolved as a zoonosis, before transfer to humans, is given detailed consideration and discussion.

Paleoecology of late Pleistocene–Holocene faunas of eastern and central Wyoming, USA, with implications for LGM climate models

Oxygen and carbon isotope compositions of teeth were measured for a variety of fossil herbivores, omnivores and carnivores from Natural Trap Cave (NTC) and Little Box Elder Cave (LBEC), central eastern Wyoming, USA. These sites host some of the best preserved and most abundant late Pleistocene to early Holocene mammal fossils, and provide key information about ecological and climatic change attending the Pleistocene–Holocene transition. Average Pleistocene compositions are consistent with C3-dominated diets, but C4 grass consumption increased in Bison from the late Pleistocene to today. A single Sangamonian Equus tooth also has elevated 13C, suggesting that C4 biomass increased during interglacials in general. Tooth δ18O values imply local water δ18O values at NTC of −15 to −16‰ during the Last Glacial Maximum (LGM) and −14‰ today, consistent with modern regional studies and general circulation models (GCM's) for the LGM. Water δ18O values at LBEC were ~−12‰. Although herbivore compositions are consistent with theoretical expectations, carnivores exhibit lower δ13C and higher δ18O values relative to herbivores than anticipated. These discrepancies could reflect poorly understood carnivore physiologies or diets, and emphasize the need for further investigation of isotope systematics in carnivores. Isotope zoning in several herbivore teeth shows negative correlations between carbon and oxygen isotopes: high and low δ18O values representing summer and winter seasons occur with low and high δ13C values respectively. This trend could indicate seasonally changing diets, e.g. consumption of drier foods or conifers during the winter, or burning of stored fat during the winter. Increasing δ18O values from the Pleistocene to Holocene in water-dependent taxa are consistent with an increasing proportion of summer moisture derived from the Gulf of Mexico, as predicted by isotope-enabled GCM's. Mean annual precipitation during the late Pleistocene is estimated at ≤350mm/yr, similar to modern day (c. 200mm/yr), indicating that dry conditions have prevailed for the last 25ka in Wyoming. A revised analytical expression for C4 plant abundance in the western US is proposed that accounts for climate variables and pCO2. Combination of this expression with the climate predictions of the PMIP2 ensemble average GCM explains LGM C4 plant abundances at NTC, southern Texas, and Florida. Changes to C4 plant abundances may provide sensitive tests of GCM accuracies.

Frequency of pathology in a large natural sample from Natural Trap Cave with special remarks on erosive disease in the Pleistocene.

Population data are presented for erosive arthritis, osteoarthritis, diffuse idiopathic skeletal hyperostosis (DISH), joint eburnation and dental injury in a fauna from Natural Trap Cave, Wyoming, represented by over thirty thousand bones from twenty-four different species. Erosive arthritis is limited to the bovids, Bison, Ovis and Bootherium. Erosive arthritis is also present in bison from the late Pleistocene Twelve Mile Creek site in Kansas and from an early Holocene site in Wisconsin. The restriction of the known Pleistocene occurrences to bovids indicate the presence of a pathogen that predisposes bovids to erosive arthritis. The pathogen was identified as Mvcobacterium tuberculosis. Osteoarthritis and DISH are rare in the Natural Trap Cave, although Bison shows a relatively high occurrence of the former. Tooth breakage due to errors in bone manipulation was a problem for carnivores and one lion, Pantera atrox, was apparently reduced by joint disease to a scavenging lifestyle.

Stratigraphic and geochronologic contexts of mammoth ( Mammuthus) and other Pleistocene fauna, Upper Missouri Basin (northern Great Plains and Rocky Mountains), U.S.A.

Mammoth fossils and other Pleistocene vertebrates from the Upper Missouri Basin, in the northern Plains and Rocky Mountains of the western interior of North America, have been dated to the late Pleistocene and are associated with Wisconsinan deposits. Mammoth remains have also been found in older stratigraphic contexts. For example, Mammuthus columbi and other fossils from the Doeden Locality are in pre-Wisconsinan terrace gravels along the Yellowstone River; the deposits are likely Illinoian or Sangamonian. Faunas that appear to be associated with the Wisconsinan interstadial, before the Last Glacial Maximum, are found in intermountain valleys and mountain settings (the Merrell Locality, Blacktail Cave, Natural Trap Cave) and on the Plains in both glaciated and unglaciated regions (Box Creek, Wibaux gravel pit). Localities containing faunas dated to the time interval from about the Last Glacial Maximum to the end of the Younger Dryas chronozone (late Wisconsinan) include the youngest fossil-bearing strata at Merrell, Blacktail Cave, Natural Trap Cave; deposits at Sheep Rock Spring, Indian Creek, MacHaffie, False Cougar Cave, Shield Trap Cave; and mammoths found at Sun River, Glendive, Colby, and the Deer Creek drainage.

Stable Isotope Values of Bone Organic Matter: Artificial Diagenesis Experiments and Paleoecology of Natural Trap Cave, Wyoming

The presence of original organic matter and retention of an indigenous isotopic signal in fossils have been disputed for years. An experiment was conducted to evaluate the influence of diagenesis on bone-protein isotope values, analyses were conducted on Holocene and Pleistocene fossils from Natural Trap Cave (NTC), Wyoming. Modern cow, Bos taurus, bone was heated with and without excess water for up to 195 hours at 100°C in an inert atmosphere. Collagen and non-collagenous proteins (NCP) were extracted and analyzed isotopically. Under dry conditions, carbon and nitrogen isotope values change by less than 0.4‰ during the 0 to 195 hour interval. In the presence of excess water, carbon and nitrogen isotope values change by no more than 1.0‰ and 0.5‰, respectively, over 192 hours. The relative abundance of amino acids of collagen from heated bone differs by less than 10% from that of unheated collagen. Protein preservation is indicated by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) that strongly indicates a portion of the original osteocalcin exists intact in samples heated for 195 hours. Good preservation of collagen in NTC fossils is implied by high collagen yields, C:N, and realistic trophic structures based on isotope values. Carbon and nitrogen isotope values of ancient collagen increase with trophic level, allow dietary assessments to be made, and differentiate between ruminant and non-ruminants. The results indicate that isotope values are resilient during simulated diagenesis and suggest that an indigenous isotopic signal can exist in well-preserved fossils such as those from NTC.