Carbon and nitrogen isotope analyses of a juvenile woolly mammoth tusk

Master of ScienceGeologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/114675/1/39015069982299.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/114675/2/39015069982299.pd

Anatomy, death, and preservation of a woolly mammoth (Mammuthus primigenius) calf, Yamal Peninsula, northwest Siberia

A well-preserved woolly mammoth calf found in northwest Siberia offers unique opportunities to investigate mammoth anatomy, behavior, life history and taphonomy. Analysis of the fluvial setting where the specimen was found suggests it was derived from eroding bluffs during ice-out flooding in June 2006. It then lay exposed on a point-bar surface until recovery the following May. AMS dating of bone collagen and plant tissues from the intestine provide age estimates that average about 41,800 14C yrBP. Anatomical features of interest include a hemispherical mass, apparently composed of brown fat, on the back of the neck. This may have functioned in thermoregulation for the neonate mammoth, born before onset of spring. Abundant subcutaneous fat and milk residues in the alimentary tract demonstrate that this animal was in good nutritional condition before death, making other features of its life history relevant for general studies of mammoth paleobiology. Plant remains from the intestine (mixed with milk residue in a manner consistent with frequent, small meals) show evidence of mastication by adult mammoths, suggesting that this calf ingested fecal material, probably from its mother and presumably to inoculate its intestinal tract with a microbial assemblage derived from a healthy adult. Discrepancies between the season of death we infer (spring) and seasonal indicators from the intestine implicate coprophagy (involving old fecal boli) by the mother. This animal’s trachea and bronchi are completely occluded with fine-grained vivianite (hydrated iron phosphate) such as occurs in some lacustrine settings. Because this vivianite does not penetrate the lung beyond the bronchi, we infer that it must have entered as a viscous mass that occluded the airway, causing asphyxia. Nodular vivianite in the cranial region and interiors of long bones must have originated postmortem, but its distribution may be partly controlled by peripheral vasoconstriction, a physiological response to asphyxia. Nodular vivianite may have formed from iron derived from hemoglobin and phosphate liberated by partial demineralization of bones. Demineralization could have been caused by lactic acid, for which the main evidence is loss of tissues dominated by Type 1 collagen (denatured in lactic acid). We propose that this was consequent on postmortem colonization of the body by lactic acid-producing bacteria. These bacteria and their metabolites may have promoted preservation during the time before the body was incorporated in permafrost and could also have inhibited scavenging and bacterial decomposition following recent exposure of the specimen.

Fluctuation of body mass in cotton rats and pocket gophers during the late Cenozoic in the Meade basin of Kansas: possible influence of the Huckleberry Ridge Ash-fall

Equations estimating body mass were used to depict a near 5-million-year history of size change in pocket gophers and cotton rats from the Meade Basin of southwestern Kansas. Although phyletic size decrease was noted in Sigmodon minor and Geomys minor and size increase in Geomys quinni, no long-term intra-basin size trends were observed. Immediately following the Huckleberry Ridge ash-fall at 2.11 Ma, the small Pliocene cotton rat S. minor became extinct, a large cotton rat entered the basin, two gophers became extinct, and two new ones entered the basin. Assuming the same rodent contingent at the Short Haul locality as at the Aries A site, between deposition of the Borchers and Short Haul assemblages, minimally about 0.12 million years, 40% of the Meade Basin rodent fauna turned over and Microtus dispersed into North America across Beringia. Geochemical environmental proxy data did not identify significant climatic events in the Borchers Badlands Pleistocene sequence; consequently it is possible that a super-eruption from the Yellowstone caldera was at least partly responsible for size shifts in cotton rats and pocket gophers and significant modifications to the Meade Basin rodent community.This work was supported by the National Geographic Society [5963-97, 6547-99]; National Science Foundation [EAR 0307582, EAR 1338262].Peer reviewe

Data from: X-Ray computed tomography of two mammoth calf mummies

Two female woolly mammoth neonates from permafrost in the Siberian Arctic are the most complete mammoth specimens known. Lyuba, found on the Yamal Peninsula, and Khroma, from northernmost Yakutia, died at ages of approximately one and two months, respectively. Both specimens were CT-scanned, yielding detailed information on the stage of development of their dentition and skeleton and insight into conditions associated with death. Both mammoths died after aspirating mud. Khroma's body was frozen soon after death, leaving her tissues in excellent condition, whereas Lyuba's body underwent postmortem changes that resulted in authigenic formation of nodules of the mineral vivianite associated with her cranium and within diaphyses of long bones. CT data provide the only comprehensive approach to mapping vivianite distribution. Three-dimensional modeling and measurement of segmented long bones permits comparison between these individuals and with previously recovered specimens. CT scans of long bones and foot bones show developmental features such as density gradients that reveal ossification centers. The braincase of Khroma was segmented to show the approximate morphology of the brain; its volume is slightly less (∼2,300 cm3) than that of neonate elephants (∼2,500 cm3). Lyuba's premaxillae are more gracile than those of Khroma, possibly a result of temporal and/or geographic variation but probably also reflective of their age difference. Segmentation of CT data and 3-D modeling software were used to produce models of teeth that were too complex for traditional molding and casting techniques

Supplemental Data 1

Animation based on segmented or thresholded features from a full-body CT-scan of Lyuba, a woolly mammoth neonate from the Yamal Peninsula, Siberi

A woolly mammoth (Mammuthus primigenius) carcass from Maly Lyakhovsky Island (New Siberian Islands, Russian Federation)

A partial carcass of an adult woolly mammoth (Mammuthus primigenius) found in 2012 on Maly Lyakhovsky Island presents a new opportunity to retrieve associated anatomical, morphological, and life history data on this important component of Pleistocene biotas. In addition, we address hematological, histological, and microbiological issues that relate directly to quality of preservation. Recovered by staff from North-Eastern Federal University in Yakutsk, this individual is a relatively old female preserving soft tissue of the anteroventral portion of the head, most of both fore-quarters, and the ventral aspect of much of the rest of the body. Both tusks were recovered and subjected to computed tomographic analysis in which annual dentin increments were revealed as cycles of variation in X-ray attenuation. Measurements of annual increment areas (in longitudinal section) display a pulsed pattern of tusk growth showing cycles of growth rate variation over periods of 3-5 years. These intervals are interpreted as calving cycles reflecting regular shifts in calcium and phosphate demand for tusk growth vs. fetal ossification and lactation. Brown liquid associated with the frozen carcass turned out to include remains of hemolyzed blood, and blood samples examined microscopically included white blood cells with preserved nuclei. Muscle tissue from the trunk was unusually well preserved, even at the histological level. Intestinal contents and tissue samples were investigated microbiologically, and several strains of lacticacid bacteria (e.g., Enterococcus faecium, Enterococcus hirae) that are widely distributed as commensal organisms in the intestines of herbivores were isolated. (C) 2017 Elsevier Ltd and INQUA. All rights reserved

Summary of the Snowmastodon Project Special Volume: A high-elevation, multi-proxy biotic and environmental record of MIS 6-4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA

In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5