Clementz, Mark T.

11 publications

Clementz, Mark T.; Hoppe, Kathryn A.; Koch, Paul L. (detail)

2003

A paleoecological paradox: the habitat and dietary preferences of the extinct tethythere Desmostylus, inferred from stable isotope analysis.
Paleobiology 29(4): 506-519. 2 tabs. 4 figs. Fall 2003 (mailed Oct. 27, 2003).
—Carbon, oxygen, and strontium isotope compositions of enamel from Desmostylus (Middle Mioc., California) indicated a probable diet of aquatic vegetation and an estuarine or freshwater habitat.

Clementz, Mark T.; Holden, P.; Koch, Paul L. (detail)
2003	Are calcium isotopes a reliable monitor of trophic level in marine setings? Intl. Jour. Osteoarchaeology 13: 29-36. —Mentions calcium isotope values (δ44Ca) for tooth enamel of Dugong dugon and Dusisiren jordani.

MacFadden, Bruce J.; Higgins, Pennilyn; Clementz, Mark T.; Jones, Douglas S. (detail)
2004	Diets, habitat preferences, and niche differentiation of Cenozoic sirenians from Florida: evidence from stable isotopes. Paleobiology 30(2): 297-324. 4 tabs. 9 figs. 1 appendix. Spring 2004 (mailed Apr. 21, 2004). —

Clementz, Mark T.; Goswami, Anjali; Gingerich, Philip D.; Koch, Paul L. (detail)
2006	Isotopic records from early whales and sea cows: contrasting patterns of ecological transition. Jour. Vert. Pal. 26(2): 355-370. 9 figs. 1 appendix. June 12, 2006. —

Clementz, Mark T.; Koch, Paul L.; Beck, Cathy A. (detail)

2007

Diet induced differences in carbon isotope fractionation between sirenians and terrestrial ungulates.
Marine Biology 151(5): 1773-1784. 2 tabs. 3 figs. + online supplementary material. DOI 10.1007/s00227-007-0616-1. Publ. online Feb. 8, 2007.
—ABSTRACT: Carbon isotope differences (?13C) between bioapatite and diet, collagen and diet, and bioapatite and collagen were calculated for four species of sirenians, Dugong dugon (Müller), Trichechus manatus (Linnaeus), Trichechus inunguis (Natterer), and the extinct Hydrodamalis gigas (Zimmerman). Bone and tooth samples were taken from archived materials collected from populations during the mid eighteenth century (H. gigas), between 1978 and 1984 (T. manatus, T. inunguis), and between 1997 and 1999 (D. dugon). Mean ?13C values were compared with those for terrestrial ungulates, carnivores, and six species of carnivorous marine mammals (cetaceans = 1; pinnipeds = 4; mustelids = 1). Significant differences in mean ?13C values among species for all tissue types were detected that separated species or populations foraging on freshwater plants or attached marine macroalgae (?13C values < ?6‰; ?13Cbioapatite–diet ?14‰) from those feeding on marine seagrasses (?13C values > ?4‰; ?13Cbioapatite–diet ?11‰). Likewise, ?13Cbioapatite–collagen values for freshwater and algal-foraging species (?7‰) were greater than those for seagrass-foraging species (?5‰). Variation in ?13C values calculated between tissues and between tissues and diet among species may relate to the nutritional composition of a species' diet and the extent and type of microbial fermentation that occurs during digestion of different types of plants. These results highlight the complications that can arise when making dietary interpretations without having first determined species-specific ?13Ctissue–diet values.

Corbett, Debra G.; Causey, Douglas; Clementz, Mark T.; Koch, Paul L.; Doroff, Angela; Lefèvre, Christine; West, Dixie (detail)
2008	Aleut hunters, sea otters, and sea cows: three thousand years of interactions in the western Aleutian Islands, Alaska. In: T.C. Rick & J.M. Erlandson (eds.), Human impacts on ancient marine systems -- a global perspective. Berkeley, Univ. Calif. Press: 43-75. 10 tabs. 5 figs. —

Clementz, Mark T.; Sorbi, Silvia; Domning, Daryl Paul (detail)
2009	Evidence of Cenozoic environmental and ecological change from stable isotope analysis of sirenian remains from the Tethys-Mediterranean region. Geology 37(4): 307-310. 2 figs. https://doi.org/10.1130/G25533A.1 Apr. 2009. —

Newsome, Seth D.; Clementz, Mark T.; Koch, Paul L. (detail)
2010	Using stable isotope biogeochemistry to study the ecology of marine mammals. Mar. Mamm. Sci. 26(3): 509-572. 3 tabs. 8 figs. July 2010. —

Clementz, Mark T.; Sewall, Jacob O. (detail)
2011	Latitudinal gradients in greenhouse seawater δ18O: evidence from Eocene sirenian tooth enamel. Science 332: 455-458. 4 figs. Supporting online material: 12 pp., 1 tab., 3 figs. Apr. 22, 2011. —Comment: Gabriel J. Bowen, "A faster water cycle", Science 332: 430-431, 1 fig., Apr. 22, 2011. Summ.: Carolyn Gramling, "Toothsome sleuths of ancient oceans", Earth 56(7): 23, 2 figs., July 2011.

Beck, Cathy A.; Clementz, Mark T. (detail)
2012	Techniques for determining the food habits of sirenians. Chap. 14 in: E. M. Hines et al. (eds.), Sirenian conservation: issues and strategies in developing countries (q.v.). Gainesville, University Press of Florida (xiv + 326): 126-132. 2 tabs. —Includes techniques for stable isotope sampling and near-infrared reflectance spectroscopy.

Kim, Sora L.; Thewissen, Johannes G. M.; Churchill, Morgan M.; Suydam, Robert S.; Ketten, Darlene R.; Clementz, Mark T. (detail)

2014

Unique biochemical and mineral composition of whale ear bones.
Physiological & Biochemical Zoology 87(4): 576-584. 3 tabs. 4 figs. DOI: 10.1086/676309. Aug. 2014.
—ABSTRACT: Cetaceans are obligate aquatic mammals derived from terrestrial artiodactyls. The defining characteristic of cetaceans is a thick and dense lip (pachyosteosclerotic involucrum) of an ear bone (the tympanic). This unique feature is absent in modern terrestrial artiodactyls and is suggested to be important in underwater hearing. Here, we investigate the mineralogical and biochemical properties of the involucrum, as these may hold clues to the aquatic adaptations of cetaceans. We compared bioapatites (enamel, dentine, cementum, and skeletal bone) of cetaceans with those of terrestrial artiodactyls and pachyosteosclerotic ribs of manatees (Sirenia). We investigated organic, carbonate, and mineral composition as well as crystal size and crystallinity index. In all studied variables, bioapatites of the cetacean involucrum were intermediate in composition and structure between those of tooth enamel on the one hand and those of dentine, cementum, and skeletal bone on the other. We also studied the amino acid composition of the cetacean involucrum relative to that of other skeletal bone. The central involucrum had low glycine and hydroxyproline concentrations but high concentrations of nonessential amino acids, unlike most bone samples but similar to the tympanic of hippos and the (pachyosteosclerotic) ribs of manatees. These amino acid results are evidence of rapid bone development. We hypothesize that the mineralogical and amino acid composition of cetacean bullae differs from that of other bone because of (1) functional modifications for underwater sound reception and (2) structural adaptations related to rapid ossification.