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Ricardo Mendes - One of the best experts on this subject based on the ideXlab platform.

Daniel C. Fisher - One of the best experts on this subject based on the ideXlab platform.

  • Evidence for the diet and habitat of two late Pleistocene Mastodons from the Midwest, USA
    Quaternary Research, 2018
    Co-Authors: Hilary H. Birks, Bas Van Geel, Daniel C. Fisher, Eric C. Grimm, Wim J. Kuijper, Jan Van Arkel, Guido Van Reenen
    Abstract:

    We analyzed intestinal contents of two late-glacial Mastodons preserved in lake sediments in Ohio (Burning Tree Mastodon) and Michigan (Heisler Mastodon). A multi-proxy suite of macrofossils and microfossils provided unique insights into what these individuals had eaten just before they died and added significantly to knowledge of Mastodon diets. We reconstructed the Mastodons’ habitats with similar multi-proxy analyses of the embedding lake sediments. Non-pollen palynomorphs, especially spores of coprophilous fungi differentiated intestinal and environmental samples. The Burning Tree Mastodon gut sample originates from the small intestine. The Heisler Mastodon sample is part of the large intestine to which humans had added clastic material to anchor parts of the carcass under water to cache the meat. Both carcasses had been dismembered, suggesting that the Mastodons had been hunted or scavenged, in line with other contemporaneous Mastodon finds and the timing of early human incursion into the Midwest. Both Mastodons lived in mixed coniferous-deciduous late-glacial forests. They browsed tree leaves and twigs, especially Picea . They also ate sedge-swamp plants and drank the lake water. Our multi-proxy estimates for a spring/summer season of death contrast with autumn estimates derived from prior tusk analyses. We document the recovered fossil remains with photographs.

  • Broken bones and hammerstones at the Cerutti Mastodon site: A reply to Haynes
    PaleoAmerica, 2017
    Co-Authors: Steven R. Holen, Daniel C. Fisher, Adam N. Rountrey, Thomas A. Deméré, Richard Fullagar, James B. Paces, George T. Jefferson, Jared M. Beeton, Kathleen A. Holen
    Abstract:

    Haynes [2017 “The Cerutti Mastodon.” PaleoAmerica 3 (3): 196–199] criticizes numerous aspects of our analysis of the Cerutti Mastodon (CM) site, but central among his points is the claim that heavy...

  • Tusk pairs in the Ziegler Reservoir Mastodon (Mammut americanum) assemblage: Implications for site taphonomy and stratigraphy
    Quaternary International, 2017
    Co-Authors: Michael D. Cherney, Daniel C. Fisher, Adam N. Rountrey
    Abstract:

    Abstract The Ziegler Reservoir (ZR) Mastodon assemblage consists of remains from dozens of individuals that represent one or more populations living in a high-elevation region of the Colorado Rocky Mountains during Marine Isotope Stage (MIS) 5. Several left-right pairs of Mastodon mandibular tusks were discovered in different stratigraphic units, challenging previous assumptions that depositional units preserving Mastodon remains sample a comparable succession of regional populations through time. It is now recognized as likely that at least some of the specimens contained in these layers were transported from original deposits located on the lake margin, and that successive slumps transported parts of the same skeleton on different occasions, depositing them in different stratigraphic units. Assigning both tusks of a pair to the lowest depositional unit in which either occurs alters the temporal pattern in season of death for ZR Mastodons and somewhat modifies a census of individuals, but does not significantly affect the secular trend previously detected in average oxygen isotope values. Two tusks with matching isotope profiles were previously treated as potential evidence of a catastrophic death event that had been proposed to explain the assemblage of remains, but these are now considered to be from the same individual. Newly paired records highlight the importance of careful taphonomic studies for any synthetic analysis of paleoecological history.

  • Sexual Dimorphism and Inter-generic Variation in Proboscidean Tusks: Multivariate Assessment of American Mastodons (Mammut americanum) and Extant African Elephants
    Journal of Mammalian Evolution, 2013
    Co-Authors: Kathlyn M. Smith, Daniel C. Fisher
    Abstract:

    Characteristics of social structure, mating strategies, and parental investment can be inferred for mammalian species based on degree of sexual dimorphism, especially when males are substantially larger than females. American Mastodons (Mammut americanum) and extant African elephants (Loxodonta africana, Loxodonta cyclotis) both exhibit marked dimorphism in tusk size. To evaluate the hypothesis that this dimorphism might be indicative of similar, and possibly conserved, behavioral patterns in each lineage, we undertook a detailed evaluation of the pattern of tusk growth in these two genera. Separate discriminant function analyses (DFA) of 21 adult Mastodon tusks of inferred sex and 48 adult elephant tusks of known sex show that patterns of ontogenetic change in tusk circumference, regardless of genus, effectively discriminate between sexes. Canonical variates analysis (CVA) of tusks from male and female Mastodons and male and female elephants shows that male tusks in both genera are larger than female tusks across all measurements, especially for maximum tusk circumference and pulp cavity depth. CVA’s emphasis of inter-group differences in tusk morphology also shows that Mastodon tusks are more robust than elephant tusks. Overall, this study illustrates that there is a characteristic male and a characteristic female tusk form shared by elephants and Mastodons. This shows that elephants and Mastodons display a shared syndrome of traits beyond sex-linked differences in tusk size, supporting the hypothesis that Mastodons exhibited behaviors similar to those we observe today in African elephants.

  • Sexual dimorphism of structures showing indeterminate growth: tusks of American Mastodons (Mammut americanum)
    Paleobiology, 2011
    Co-Authors: Kathlyn M. Smith, Daniel C. Fisher
    Abstract:

    Abstract Documenting sexual dimorphism for structures that exhibit indeterminate growth can be more difficult than for structures exhibiting determinate growth. Most proboscidean tusks are ever-growing structures that change size and shape throughout life. Sexual dimorphism is pronounced in tusks of mature individuals, but the external form of tusks offers no clear evidence of maturation, and it is difficult to distinguish a young male's tusk from that of an older female. Thus, with previous approaches, knowledge of age was often required to assess sex from tusk measurements. This study examines sexual dimorphism of American Mastodon (Mammut americanum) tusks through principal components analysis to determine which aspects of tusk form contribute most strongly to the variance among measurements and to explore the relationship between tusk form and individual age and sex. Twenty-one Mastodon tusks from the Great Lakes region were evaluated in two analyses, the first focusing on geometrically distinct aspec...

Johannes Van Der Plicht - One of the best experts on this subject based on the ideXlab platform.

  • the muirkirk mammoth a late pleistocene woolly mammoth mammuthus primigenius skeleton from southern ontario canada
    Quaternary International, 2012
    Co-Authors: C.r. Harington, Johannes Van Der Plicht
    Abstract:

    Abstract The Muirkirk Mammoth, found in 1895 2.4 km northeast of the village of Muirkirk in southern Ontario, is the most complete woolly mammoth (Mammuthus primigenius) skeleton known from Canada. Approximate tusk measurements and extreme wear on the sixth molars indicate it is best referred to an old male. Its geological age was controversial because the first two Holocene bone collagen radiocarbon dates were derived evidently from contaminated samples. Three new radiocarbon dates on carefully selected bone and ivory are close, averaging 12,190 BP, and indicate that this mammoth died before the close of the Wisconsinan glaciation and near the time of extinction of woolly mammoths in this part of North America. Its assignment to regional pollen subzone 1b suggests that, like the Rostock Mammoth of similar age from southern Ontario, it lived in a tundra woodland environment. The Highgate Mastodon (Mammut americanum) and giant beaver (Castoroides ohioensis) found 4 km away and also assigned to pollen subzone 1b suggests that some spruce wetlands characterised the tundra woodland environment, and that perhaps woolly mammoths and American Mastodons lived almost side by side in southern Ontario about12,000 radiocarbon years or 14,000 calendar years ago. The Muirkirk Mammoth is discussed in relation to the dispersal history of woolly mammoths.

Kathlyn M. Smith - One of the best experts on this subject based on the ideXlab platform.

  • Sexual Dimorphism and Inter-generic Variation in Proboscidean Tusks: Multivariate Assessment of American Mastodons (Mammut americanum) and Extant African Elephants
    Journal of Mammalian Evolution, 2013
    Co-Authors: Kathlyn M. Smith, Daniel C. Fisher
    Abstract:

    Characteristics of social structure, mating strategies, and parental investment can be inferred for mammalian species based on degree of sexual dimorphism, especially when males are substantially larger than females. American Mastodons (Mammut americanum) and extant African elephants (Loxodonta africana, Loxodonta cyclotis) both exhibit marked dimorphism in tusk size. To evaluate the hypothesis that this dimorphism might be indicative of similar, and possibly conserved, behavioral patterns in each lineage, we undertook a detailed evaluation of the pattern of tusk growth in these two genera. Separate discriminant function analyses (DFA) of 21 adult Mastodon tusks of inferred sex and 48 adult elephant tusks of known sex show that patterns of ontogenetic change in tusk circumference, regardless of genus, effectively discriminate between sexes. Canonical variates analysis (CVA) of tusks from male and female Mastodons and male and female elephants shows that male tusks in both genera are larger than female tusks across all measurements, especially for maximum tusk circumference and pulp cavity depth. CVA’s emphasis of inter-group differences in tusk morphology also shows that Mastodon tusks are more robust than elephant tusks. Overall, this study illustrates that there is a characteristic male and a characteristic female tusk form shared by elephants and Mastodons. This shows that elephants and Mastodons display a shared syndrome of traits beyond sex-linked differences in tusk size, supporting the hypothesis that Mastodons exhibited behaviors similar to those we observe today in African elephants.

  • Sexual dimorphism of structures showing indeterminate growth: tusks of American Mastodons (Mammut americanum)
    Paleobiology, 2011
    Co-Authors: Kathlyn M. Smith, Daniel C. Fisher
    Abstract:

    Abstract Documenting sexual dimorphism for structures that exhibit indeterminate growth can be more difficult than for structures exhibiting determinate growth. Most proboscidean tusks are ever-growing structures that change size and shape throughout life. Sexual dimorphism is pronounced in tusks of mature individuals, but the external form of tusks offers no clear evidence of maturation, and it is difficult to distinguish a young male's tusk from that of an older female. Thus, with previous approaches, knowledge of age was often required to assess sex from tusk measurements. This study examines sexual dimorphism of American Mastodon (Mammut americanum) tusks through principal components analysis to determine which aspects of tusk form contribute most strongly to the variance among measurements and to explore the relationship between tusk form and individual age and sex. Twenty-one Mastodon tusks from the Great Lakes region were evaluated in two analyses, the first focusing on geometrically distinct aspec...

Jeheskel Shoshani - One of the best experts on this subject based on the ideXlab platform.

  • Phylogenetic resolution within the Elephantidae using fossil DNA sequence from the American Mastodon (Mammut americanum) as an outgroup.
    Proceedings of the National Academy of Sciences of the United States of America, 1996
    Co-Authors: Hong Yang, Edward M. Golenberg, Jeheskel Shoshani
    Abstract:

    Abstract DNA was extracted from the extinct American Mastodon, the extinct woolly mammoth, and the modern Asian and African elephants to test the traditional morphologically based phylogeny within Elephantidae. Phylogenetic analyses of the aligned sequences of the mitochondrial gene cytochrome b support a monophyletic Asian elephant-woolly mammoth clade when the American Mastodon is used as an outgroup. Previous molecular studies were unable to resolve the relationships of the woolly mammoth, Asian elephant, and African elephant because the sequences appear to have evolved at heterogeneous rates and inappropriate outgroups were used for analysis. The results demonstrate the usefulness of fossil molecular data from appropriate sister taxa for resolving phylogenies of highly derived or early radiating lineages.