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A multivariate approach to infer locomotor modes in Mesozoic mammals

Published online by Cambridge University Press:  24 February 2015

Meng Chen  and
Gregory P. Wilson
Meng Chen
Affiliation:
Department of Biology, University of Washington, Seattle, Washington 98195, U.S.A. E-mail: mengchen@uw.edu; gpwilson@uw.edu
Gregory P. Wilson
Affiliation:
Department of Biology, University of Washington, Seattle, Washington 98195, U.S.A. E-mail: mengchen@uw.edu; gpwilson@uw.edu
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Abstract

Ecomorphological diversity of Mesozoic mammals was presumably constrained by selective pressures imposed by contemporary vertebrates. In accordance, Mesozoic mammals for a long time had been viewed as generalized, terrestrial, small-bodied forms with limited locomotor specializations. Recent discoveries of Mesozoic mammal skeletons with distinctive postcranial morphologies have challenged this hypothesis. However, ecomorphological analyses of these new postcrania have focused on a single taxon, a limited region of the skeleton, or have been largely qualitative.

For more comprehensive locomotor inference in Mesozoic mammals, we applied multivariate analyses to a morphometric data set of extant small-bodied mammals. We used 30 osteological indices derived from linear measurements of appendicular skeletons of 107 extant taxa that sample 15 orders and eight locomotor modes. Canonical variate analyses show that extant small-bodied mammals of different locomotor modes have detectable and predictable morphologies. The resulting morphospace occupation reveals a morphofunctional continuum that extends from terrestrial to scansorial, arboreal, and gliding modes, reflecting an increasingly slender postcranial skeleton with longer limb output levers adapted for speed and agility, and extends from terrestrial to semiaquatic/semifossorial and fossorial modes, reflecting an increasingly robust postcranial skeleton with shorter limb output levers adapted for powerful, propulsive strokes. We used this morphometric data set to predict locomotor mode in ten Mesozoic mammals within the Docodonta, Multituberculata, Eutriconodonta, “Symmetrodonta,” and Eutheria. Our results indicate that these fossil taxa represent five of eight locomotor modes used to classify extant taxa in this study, in some cases confirming and in other cases differing from prior ecomorphological assessments. Together with previous locomotor inferences of 19 additional taxa, these results show that by the Late Jurassic mammals had diversified into all but the saltatorial and active flight locomotor modes, and that this diversification was greatest in the Eutriconodonta and Multituberculata, although sampling of postcranial skeletons remains uneven across taxa and through time.

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Paleobiology , Volume 41 , Issue 2 , March 2015 , pp. 280 - 312
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Copyright © 2015 The Paleontological Society. All rights reserved. 

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References

Literature Cited

Alexander, R. M. 1985. Body support, scaling, and allometry. Pp. 26–37 In Hildebrand et al. 1985.Google Scholar
Alexander, R. M, Jayes, A. S., Maloiy, G. M., and Wathuta, E. M.. 1981. Allometry of the leg muscles of mammals. Journal of Zoology 194:539–552.Google Scholar
Allin, E.F., and Hopson, J. A.. 1992. Evolution of the auditory system in Synapsida (“mammal-like reptiles” and primitive mammals) as seen in the fossil record. Pp. 587–614In D. B. Webster, R. R. Fay, and A. N. Popper, eds. The evolutionary biology of hearing. Springer, New York.CrossRefGoogle Scholar
Argot, C. 2001. Functional-adaptive anatomy of the forelimb in the Didelphidae, and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus. Journal of Morphology 247:51–79.Google Scholar
Argot, C 2002. Functional-adaptive analysis of the hindlimb anatomy of extant marsupials and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus. Journal of Morphology 253:76–108.Google Scholar
Augee, M., Gooden, B., and Musser, A.. 2006. Echidna: extraordinary egg-laying mammal. CSIRO Publishing, Collingwood, Australia.Google Scholar
Bassarova, M., Janis, C. M., and Archer, M.. 2009. The calcaneum—on the heels of marsupial locomotion. Journal of Mammalian Evolution 16:1–23.Google Scholar
Beard, K. C. 1993. Origin and evolution of gliding in Early Cenozoic Dermoptera (Mammalia, Primatomorpha). Pp. 63–90In R. D. E. MacPhee, ed. Primates and their relatives in phylogenetic perspective. Plenum, New York.Google Scholar
Biewener, A. A. 1989. Mammalian terrestrial locomotion and size. Bioscience 39:776–783.CrossRefGoogle Scholar
Biewener, A. A 1990. Biomechanics of mammalian terrestrial locomotion. Science 250:1097.Google Scholar
Biewener, A. A 2003. Animal locomotion. Oxford University Press, Oxford.Google Scholar
Bloch, J. I., and Boyer, D. M.. 2002. Grasping primate origins. Science 298:1606–1610.Google Scholar
Boyer, D. M., Yapuncich, G. S., Chester, S. G. B., Bloch, J. I., and Godinot, M.. 2013. Hands of early primates. Yearbook of Physical Anthropology 57:33–78.CrossRefGoogle Scholar
Borths, M., and Hunter, J. P.. 2008. Gimme shelter? Locomotor trends and mammalian survivorship at the K/Pg boundary. Journal of Vertebrate Paleontology 28:54–55A.Google Scholar
Bourlière, F. 1975. Mammals, small and large: the ecological implications of size. Pp. 1–8in F. B. Golley, K. Petrusewicz, and L. Ryszkowski, eds. Small mammals: their productivity and population dynamics. Cambridge University Press, Cambridge.Google Scholar
Bover, P., Alcover, J. A., Michaux, J. J., Hautier, L., and Hutterer, R.. 2010. Body shape and life style of the extinct Balearic dormouse Hypnomys (Rodentia, Gliridae): new evidence from the study of associated skeletons. PLoS ONE 5(12):e15817. doi:10.1371/journal.pone.0015817.Google Scholar
Carrano, M. T. 1999. What, if anything, is cursor? Categories versus continua for determining locomotor habit in mammals and dinosaurs. Journal of Zoology 247:29–42.Google Scholar
Cartmill, M. 1985. Climbing. Pp. 73–88 In Hildebrand et al. 1985.Google Scholar
Chen, M., and Luo, Z.-X.. 2013. Postcranial skeleton of the Cretaceous mammal Akidolestes cifellii and its locomotor adaptations. Journal of Mammalian Evolution 20:159–189.Google Scholar
Chester, S. G. B., Sargis, E. J., Szalay, F. S., Archibald, J. D., and Averianov, A. O.. 2010. Mammalian distal humeri from the Late Cretaceous of Uzbekistan. Acta Palaeontologica Polonica 55:199–211.Google Scholar
Chester, S. G. B., Sargis, E. J., Szalay, F. S., Archibald, J. D., and Averianov, A. O.. 2012. Therian femora from the Late Cretaceous of Uzbekistan. Acta Palaeontologica Polonica 57:53–64.Google Scholar
Croft, D. A., and Anderson, L. C.. 2008. Locomotion in the extinct notoungulate Protypotherium. Palaeontologia Electronica 11:1–20.Google Scholar
Degen, A. A. 1997. Ecophysiology of small desert mammals. Springer, Berlin.Google Scholar
Dunstone, N. 1979. Swimming and diving behavior of the mink (Mustela vison Schreber). Carnivore 2:56–61.Google Scholar
Elissamburu, A., and Vizcaíno, S. F.. 2004. Limb proportions and adaptations in caviomorph rodents (Rodentia: Caviomorpha). Journal of Zoology 262:145–159.Google Scholar
Emerson, S. B. 1985. Jumping and leaping. Pp. 58–72 in Hildebrand et al. 1985.Google Scholar
Evans, A. R. 2013. Shape descriptors as ecometrics in dental ecology. Hystrix, Italian Journal of Mammalogy 24:133–140.Google Scholar
Fish, F. E. 1993. Influence of hydrodynamic design and propulsive mode on mammalian swimming energetics. Australian Journal of Zoology 42:79–101.Google Scholar
Fox, R. C., and Naylor, B. G.. 2006. Stagodontid marsupials from the Late Cretaceous of Canada and their systematic and functional implications. Acta Palaeontologica Polonica 51:13–36.Google Scholar
Fröbisch, J., and Reisz, R. R.. 2009. The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems. Proceedings of Royal Society of London B 276:3611–3618.Google Scholar
Gaetano, L. C., and Rougier, G. W.. 2011. New materials of Argentoconodon fariasorum (Mammaliaformes, Triconodontidae) from the Jurassic of Argentina and its bearing on triconodont phylogeny. Journal of Vertebrate Paleontology 31:829–843.CrossRefGoogle Scholar
Gaetano, L. C., and Rougier, G. W.. 2012. First amphilestid from South America: a molariform from the Jurassic Cañadón Asfalto Formation, Patagonia, Argentina. Journal of Mammalian Evolution 19:235–248.Google Scholar
Gambaryan, P. P. 1974. How mammals run: anatomical adaptations. Wiley, New York.Google Scholar
Gambaryan, P. P., and Kielan-Jaworowska, Z.. 1997. Sprawling versus parasagittal stance in multituberculate mammals. Acta Palaeontologica Polonica 42:13–44.Google Scholar
Gingerich, P. D. 2003. Land-to-sea transition in early whales: evolution of Eocene Archaeoceti (Cetacea) in relation to skeletal proportions and locomotion of living semiaquatic mammals. Paleobiology 29:429–454.2.0.CO;2>CrossRefGoogle Scholar
Grillner, S., and Wallén, P.. 1985. The ionic mechanisms underlying N-methyl-D-aspartate receptor-induced, tetrodotoxin-resistant membrane potential oscillations in lamprey neurons active during locomotion. Neuroscience Letter 60:289–294.Google Scholar
Grossnickle, D. M., and Polly, P. D.. 2013. Mammal disparity decreases during the Cretaceous angiosperm radiation. Proceedings of the Royal Society of London B 280:20132110. doi: 10.1098/rspb.2013.2110.Google ScholarPubMed
Hildebrand, M. 1985. Digging in quadrupeds. Pp. 89–109 in Hildebrand et al. 1985.Google Scholar
Hildebrand, M., and Goslow, G.. 1998. Analysis of vertebrate structure. Wiley, New York.Google Scholar
Hildebrand, M., Bramble, D. M., Liem, K. F., and Wake, D. B., eds. 1985. Functional vertebrate morphology. Harvard University Press, Cambridge.Google Scholar
Hopkins, S. S. B., and Davis, E. B.. 2009. Quantitative morphological proxies for fossoriality in small mammals. Journal of Mammalogy 90:1449–1460.Google Scholar
Horovitz, I. 2003. Postcranial skeleton of Ukhaatherium nessovi (Eutheria, Mammalia) from the Late Cretaceous of Mongolia. Journal of Vertebrate Paleontology 23:857–868.CrossRefGoogle Scholar
Howell, A. B. 1930. Aquatic mammals. Charles C. Thomas, Springfield, Ill.Google Scholar
Hu, Y.-M. 2006. Postcranial morphology of Repenomamus (Eutriconodonta, Mammalia): implications for the higher-level phylogeny of mammals. Ph.D. dissertation. City University of New York, New York.Google Scholar
Hu, Y.-M., and Wang, Y.-Q.. 2002. Sinobaatar gen. nov.: first multituberculate from the Jehol Biota of Liaoning, northeast China. Chinese Science Bulletin 47:933–938.Google Scholar
Hu, Y.-M., Wang, Y.-Q., Luo, Z.-X., and Li, C.-K.. 1997. A new symmetrodont mammal from China and its implications for mammalian evolution. Nature 390:137–142.Google Scholar
Hu, Y.-M., Wang, Y.-Q., Li, C.-K., and Luo, Z.-X.. 1998. Morphology of dentition and forelimb of Zhangheotherium. Vertebrata PalAsiatica 36:102–125.Google Scholar
Hu, Y.-M., Meng, J., Wang, Y.-Q., and Li, C.-K.. 2005. Large Mesozoic mammals fed on young dinosaurs. Nature 433:149–152.Google Scholar
Hurum, J. H., and Kielan-Jaworowska, Z.. 2008. Postcranial skeleton of a Cretaceous multituberculate mammal Catopsbaatar. Acta Palaeontologica Polonica 53:545–566.Google Scholar
Iwaniuk, A. N., Pellis, S. M., and Whishaw, I. Q.. 1999. The relationship between forelimb morphology and behaviour in North American carnivores (Carnivora). Canadian Journal of Zoology 77:1064–1074.Google Scholar
Janis, C. M., Theodor, J. M., and Boisvert, B.. 2002. Locomotor evolution in camels revisited: a quantitative analysis of pedal anatomy and the acquisition of the pacing gait. Journal of Vertebrate Paleontology 22:110–121.Google Scholar
Jäger, K., Luo, Z.-X., and Martin, T.. 2013. CT scanning and 3D image analysis of the postcranial skeleton of Henkelotherium guimarotae (Cladotheria, Mammalia) from the Late Jurassic of Portugal and its locomotor adaptations. Society of Vertebrate Paleontology 73rd, Program and Abstracts, p. 147. Journal of Vertebrate Paleontology (online supplement), October 2013.Google Scholar
Jenkins, F. A. 1970. Limb movements in a monotreme (Tachyglossus aculeatus): a cineradiographic analysis. Science 168:1473–1475.Google Scholar
Jenkins, F. A 1974. Tree shrew locomotion and arborealism. Pp. 85–115in F. A. Jenkins, ed. Primate locomotion. Academy Press, New York.Google Scholar
Jenkins, F. A., and Parrington, F.. 1976. Postcranial skeletons of Triassic mammals Eozostrodon, Megazostrodon and Erythrotherium. Philosophical Transactions of the Royal Society of London B 273:387–431.Google Scholar
Jenkins, F. A., and Schaff, C. R.. 1988. The Early Cretaceous mammal Gobiconodon (Mammalia, Triconodonta) from the Cloverly Formation in Montana. Journal of Vertebrate Paleontology 8:1–24.Google Scholar
Jerison, H. J. 1973. Evolution of the brain and intelligence. Academic Press, New York.Google Scholar
Ji, Q., Luo, Z.-X., and Ji, S.-A.. 1999. A Chinese triconodont mammal and mosaic evolution of the mammalian skeleton. Nature 398:326–330.Google Scholar
Ji, Q., Luo, Z.-X., Yuan, C.-X., Wible, J. R., Zhang, J.-P., and Georgi, J. A.. 2002. The earliest known eutherian mammal. Nature 416:816–822.Google Scholar
Ji, Q., Luo, Z.-X., Yuan, C.-X., and Tabrum, A. R.. 2006. A swimming mammaliaform from the Middle Jurassic and ecomorphological diversification of early mammals. Science 311:1123–1127.Google Scholar
Jouffroy, F. K., and Lessertisseur, J.. 1979. Relationships between limb morphology and locomotor adaptations among prosimians: an osteometric study. Pp. 143–181In M. E. Morbeck, H. Preuschoft, and N. Gomberg, eds. Environment, behavior, and morphology: dynamic interactions in primates. Gustav Fischer, New York.Google Scholar
Jouffroy, F. K., Godinot, M., and Nakano, Y.. 1993. Biometrical characteristics of primate hands. Pp. 133–171In H. Preuschoft and D. J. Chivers, eds. Hands of primates. Springer, New York.Google Scholar
Kardong, K. V. 2009. Vertebrates: comparative anatomy, function, evolution. McGraw-Hill, New York.Google Scholar
Kelt, D. A., and Meyer, M. D.. 2009. Body size frequency distributions in African mammals are bimodal at all spatial scales. Global Ecology and Biogeography 18:19–29.Google Scholar
Kielan-Jaworowska, Z. 1978. Evolution of the therian mammals in the Late Cretaceous of Asia. Part III. Postcranial skeleton in Zalambdalestidae. Acta Palaeontologia Polonica 38:5–41.Google Scholar
Kielan-Jaworowska, Z., and Gambaryan, P. P.. 1994. Postcranial anatomy and habits of Asian multituberculate mammals. Fossil and Strata 36:1–92.Google Scholar
Kielan-Jaworowska, Z., Cifelli, R. L., and Luo, Z.-X.. 2004. Mammals from the age of dinosaurs: origins, evolution, and structure. Columbia University Press, New York.Google Scholar
Kingdon, J. 1997. The Kingdon field guide to African mammals. Academic Press, San Diego.Google Scholar
Kirk, E. C., Lemelin, P., Hamrick, M. W., Boyer, D. M., and Bloch, J. I.. 2008. Intrinsic hand proportions of euarchontans and other mammals: implications for the locomotor behavior of plesiadapiforms. Journal of Human Evolution 55:278–299.Google Scholar
Klima, M. 1973. Die Frühentwicklung des Schultergürtels und des Brustbeins bei den Monotremen (Mammalia: Prototheria). Advances in Anatomy, Embryology and Cell Biology 47:1–80.Google Scholar
Krause, D. W., and Jenkins, F. A.. 1983. The postcranial skeleton of North American multituberculates. Bulletin of the Museum of Comparative Zoology 150:199–246.Google Scholar
Krebs, B. 1991. Das Skelett von Henkelotherium guimarotae gen. et sp. nov. (Eupantotheria, Mammalia) aus dem Oberen Jura yon Portugal. Berliner Geowissenschaftliche Abhandlungen A 133:1–121.Google Scholar
Kühne, W. G. 1956. The Liassic therapsid Oligokyphus. British Museum (Natural History), London.Google Scholar
Lanyon, L. E., and Rubin, C. T.. 1985. Functional adaptation in skeletal structures. Pp. 1–25 In Hildebrand et al. 1985.Google Scholar
Lemelin, P. 1999. Morphological correlates of substrate use in didelphid marsupials: implications for primate origins. Journal of Zoology 247:165–175.Google Scholar
Li, G., and Luo, Z.-X.. 2006. A Cretaceous symmetrodont therian with some monotreme-like postcranial features. Nature 439:195–200.Google Scholar
Lillegraven, J. A., Kielan-Jaworowska, Z., and Clemens, W. A.. 1979. Mesozoic mammals: the first two-thirds of mammalian history. University of California Press, Berkeley.Google Scholar
Longrich, N. 2004. Aquatic specialization in mammals from the Late Cretaceous of North America. Journal of Vertebrate Paleontology 24(Suppl. to No. 3): 84A.Google Scholar
Luo, Z.-X. 2007. Transformation and diversification in early mammal evolution. Nature 450:1011–1019.Google Scholar
Luo, Z.-X., and Ji, Q.. 2005. New study on dental and skeletal features of the Cretaceous “symmetrodontan” mammal Zhangheotherium. Journal of Mammalian Evolution 12:337–357.Google Scholar
Luo, Z.-X., and Wible, J. R.. 2005. A Late Jurassic digging mammal and early mammalian diversification. Science 308:103–107.Google Scholar
Luo, Z.-X., Cifelli, R. L., and Kielan-Jaworowska, Z.. 2001a. Dual origin of tribosphenic mammals. Nature 409:53–57.Google Scholar
Luo, Z.-X., Crompton, A. W., and Sun, A.-L.. 2001b. A new mammaliaform from the early Jurassic and evolution of mammalian characteristics. Science 292:1535–1540.Google Scholar
Luo, Z.-X., Ji, Q., Wible, J. R., and Yuan, C.-X.. 2003. An Early Cretaceous tribosphenic mammal and metatherian evolution. Science 302:1934–1940.Google Scholar
Luo, Z.-X., Chen, P.-J., Li, G., and Chen, M.. 2007. A new eutriconodont mammal and evolutionary development in early mammals. Nature 446:288–293.Google Scholar
MacLeod, N., and Rose, K. D.. 1993. Inferring locomotor behavior in Paleogene mammals via eigenshape analysis. American Journal of Science 293A:300–355.Google Scholar
Martin, T. 2005. Postcranial anatomy of Haldanodon exspectatus (Mammalia, Docodonta) from the Late Jurassic (Kimmeridgian) of Portugal and its bearing for mammalian evolution. Zoological Journal of the Linnean Society 145:219–248.Google Scholar
Martin, T 2013. Mammalian postcranial bones from the Late Jurassic of Portugal and their implications for forelimb evolution. Journal of Vertebrate Paleontology 33:1432–1441.Google Scholar
Marshall, L. G. 1978. Chironectes minimus. Mammalian Species 109:1–6.Google Scholar
McMahon, T. A. 1975. Using body size to understand the structural design of animals: quadrupedal locomotion. Journal of Applied Physiology 39:619–627.Google Scholar
McNab, B. K. 1990. Physiological significance of body size. Pp. 11–24In J. D. Damuth and B. J. MacFadden, eds. Body size in mammalian paleobiology: estimation and biological implications. Cambridge University Press, Cambridge.Google Scholar
McNab, B. K 2002. The physiological ecology of vertebrates: a view from energetics. Cornell University Press, New York.Google Scholar
Meng, J., Hu, Y.-M., Wang, Y.-Q., Wang, X.-L., and Li, C.-K.. 2006. A Mesozoic gliding mammal from northeastern China. Nature 444:889–893.Google Scholar
Merritt, J. F. 2010. The biology of small mammals. Johns Hopkins University Press, Baltimore.Google Scholar
Nakagawa, M., Miguchi, H., Sato, K., Shoko, S., and Nakashizuka, T.. 2007. Population dynamics of arboreal and terrestrial small mammals in a tropical rainforest, Sarawak, Malaysia. Raffles Bulletin of Zoology 55:389–395.Google Scholar
Nowak, R. M. 1999. Walker’s mammals of the world. Johns Hopkins University Press, Baltimore.Google Scholar
Nowak, R. M 2005. Walker’s marsupials of the world. Johns Hopkins University Press, Baltimore.Google Scholar
O’Keefe, F. R, and Carrano, M. T.. 2005. Correlated trends in the evolution of the plesiosaur locomotor system. Paleobiology 31:656–675.Google Scholar
Polly, P. D. 2007. Limbs in mammalian evolution. Pp. 245–268In B. K. Hall, ed. Fins into limbs: evolution, development and transformation. University of Chicago Press, Chicago.Google Scholar
Polly, P. D 2008. Adaptive zones and the pinniped ankle: a three-dimensional quantitative analysis of carnivoran tarsal evolution. Pp. 167–196In E. J. Sargis and M. Dagosto, eds. Mammalian evolutionary morphology. Springer, Dordrecht.Google Scholar
Polly, P. D 2011. Tiptoeing through the trophics: geographic variation in carnivoran locomotor ecomorphology in relation to environment. Pp. 374–410In A. Goswami and A. R. Friscia, eds. Carnivoran evolution: new views on phylogeny, form and function. Cambridge University Press, Cambridge.Google Scholar
Rowe, T. B. 1996. Coevolution of the mammalian middle ear and neocortex. Science 273:651–654.Google Scholar
Rowe, T. B., Macrini, T. E., and Luo, Z. X.. 2011. Fossil evidence on origin of the mammalian brain. Science 332:955–957.Google Scholar
Salton, J. A. and Sargis, E. J.. 2008. Evolutionary morphology of the Tenrecoidea (Mammalia) forelimb skeleton. Pp. 51–77In E. J. Sargis and M. Dagosto, eds. Mammalian evolutionary morphology. Springer, Dordrecht.Google Scholar
Samuels, J. X., and Van Valkenburgh, B.. 2008. Skeletal indicators of locomotor adaptations in living and extinct rodents. Journal of Morphology 269:1387–1411.Google Scholar
Samuels, J. X., Meachen, J. A., and Sakai, S. A.. 2013. Postcranial morphology and the locomotor habits of living and extinct carnivorans. Journal of Morphology 274:121–146.Google Scholar
Sargis, E. J. 2001a. The grasping behaviour, locomotion and substrate use of the tree shrews Tupaia minor and T. tana (Mammalia, Scandentia). Journal of Zoology 253:485–490.Google Scholar
Sargis, E. J 2001b. A preliminary qualitative analysis on the axial skeleton of tupaiids (Mammalia, Scandentia): functional morphology and phylogenetic implications. Journal of Zoology, London 253:473–483.Google Scholar
Sargis, E. J 2002a. Functional morphology of the forelimb of tupaiids (Mammalia. Scandentia) and its phylogenetic implications. Journal of Morphology 253:10–42.Google Scholar
Sargis, E. J 2002b. Functional morphology of the hindlimb of tupaiids (Mammalia. Scandentia) and its phylogenetic implications. Journal of Morphology 254:149–185.Google Scholar
Schilling, N., and Fischer, M. S.. 1999. Kinematic analysis of treadmill locomotion of tree shrews, Tupaia glis (Scandentia: Tupaiidae). Zeitschrift für Säugetierkunde (International Journal of Mammalian Biology) 64:1–25.Google Scholar
Sereno, P. 2006. Shoulder girdle and forelimb in multituberculates: evolution of parasagittal forelimb posture in mammals. Pp. 315–366In M. T. Carrano, T. J. Gaudin, R. W. Blob, and J. R. Wible, eds. Amniote paleobiology: perspectives on the evolution of mammals, birds, and reptiles. University of Chicago Press, Chicago.Google Scholar
Shattuck, M. R., and Williams, S. A.. 2010. Arboreality has allowed for the evolution of increased longevity in mammals. Proceedings of the National Academy of Sciences USA 107:4635–4639.Google Scholar
Shimer, H. W. 1903. Adaptations to aquatic, arboreal, fossorial, and cursorial habits in mammals. III. Fossorial adaptations. American Naturalist 37:819–825.Google Scholar
Sokal, R. R., and Rohlf, F. J.. 2012. Biometry: the principles and practice of statistics in biological research, 4th ed. W. H. Freeman, New York.Google Scholar
Stein, B. R. 1988. Morphology and allometry in several genera of semiaquatic rodents (Ondatra, Nectomys, and Oryzomys). Journal of Mammalogy 69:500–511.Google Scholar
Stein, B. R 2000. Morphology of subterranean rodents. Pp. 19–61In E. A. Lacey, J. L. Patton, and G. N. Cameron, eds. Life underground: the biology of subterranean rodents. University of Chicago Press, Chicago.Google Scholar
Stoddart, D. M. 1979. Ecology of small mammals. Chapman and Hall, London.Google Scholar
Stucky, R. K. 1990. Evolution of land mammal diversity in North America during the Cenozoic. Current Mammalogy 2:375–432.Google Scholar
Sues, H.-D., and Jenkins, F. A.. 2006. The postcranial skeleton of Kayentatherium wellesi from the Lower Jurassic Kayenta Formation of Arizona and the phylogenetic significance of postcranial features. Pp. 114–152In M. T. Carrano, T. J. Gaudin, R. W. Blob, and J. R. Wible, eds. Amniote paleobiology: perspectives on the evolution of mammals, birds, and reptiles. University of Chicago Press, Chicago.Google Scholar
Sun, A., and Li, Y.. 1985. The postcranial skeleton of the late tritylodont Bienotheroides. Vertebrata PalAsiatica 23:135–151.Google Scholar
Szalay, F. S. 1984. Arboreality: is it homologous in metatherian and eutherian mammals? Evolutionary Biology 18:215–258.Google Scholar
Szalay, F. S 1994. Evolutionary history of the marsupials and an analysis of osteological characters. Cambridge University Press, New York.Google Scholar
Szalay, F. S., and Sargis, E. J.. 2001. Model-based analysis of postcranial osteology of marsupials from the Palaeocene of Itaboraí (Brazil) and the phylogenetics and biogeography of Metatheria. Geodiversitas 23:139–302.Google Scholar
Tucker, V. A. 1970. Energetic cost of locomotion in animals. Comparative Biochemistry and Physiology 34:841–846.Google Scholar
Tucker, V. A 1975. The energetic cost of moving about. American Scientist 63:413–419.Google Scholar
Ungar, P. S., and Williamson, M.. 2000. Exploring the effects of tooth wear on functional morphology: a preliminary study using dental topographic analysis. Palaeontologia Electronica 3:1–18.Google Scholar
Van Valen, L., and Sloan, R. E.. 1977. Ecology and the extinction of the dinosaurs. Evolutionary Theory 2:37–64.Google Scholar
Van Valkenburgh, B. 1987. Skeletal indicators of locomotor behavior in living and extinct carnivores. Journal of Vertebrate Paleontology 7:162–182.Google Scholar
Van Valkenburgh, B., and Koepfli, K. P.. 1993. Cranial and dental adaptations to predation in canids. Symposium of the Zoological Society of London 65:15–37.Google Scholar
Vázquez-Molinero, R., Martin, T., Fischer, M. S., and Frey, R.. 2001. Comparative anatomical investigations of the postcranial skeleton of Henkelotherium guimarotae Krebs, 1991 (Eupantotheria, Mammalia) and their implications for its locomotion. Zoosystematics and Evolution 77:207–216.Google Scholar
Venables, W. N., and Ripley, B. D.. 2002. Modern applied statistics with S. Springer, New York.Google Scholar
Weisbecker, V., and Schmid, S.. 2007. Autopodial skeletal diversity in hystricognath rodents: functional and phylogenetic aspects. Mammalian Biology – Zeitschrift für Säugetierkunde 72:27–44.Google Scholar
Weisbecker, V., and Warton, D. I.. 2006. Evidence at hand: diversity, functional implications, and locomotor prediction in intrinsic hand proportions of diprotodontian marsupials. Journal of Morphology 267:1469–1485.Google Scholar
Wilson, G. P. 2013. Mammals across the K/Pg boundary in northeastern Montana, U.S.A.: dental morphology and body-size patterns reveal extinction selectivity and immigrant-fueled ecospace filling. Paleobiology 39:429–469.CrossRefGoogle Scholar
Wilson, D. E., and Reeder, D. M.. 2005. Mammal species of the world: a taxonomic and geographic reference. Johns Hopkins University Press, Baltimore.Google Scholar
Wilson, G. P., Evans, A. R., Corfe, I. J., Smits, P. D., Fortelius, M., and Jernvall, J.. 2012. Adaptive radiation of multituberculate mammals before the extinction of dinosaurs. Nature 483:457–460.Google Scholar
Wing, S. L., and Tiffney, B. H.. 1987. Interactions of angiosperms and herbivorous tetrapods through time. Pp. 203–224In E. M. Friis, W. G. Chaloner, and P. R. Crane, eds. The origins of angiosperms and their biological consequences. Cambridge University Press, New York.Google Scholar
Yuan, C.-X., Ji, Q., Meng, Q.-J., Tabrum, A. R., and Luo, Z.-X.. 2013. A new Jurassic mammal and origins of diverse feeding and locomotor adaptation multituberculate mammals. Science 341:779–783.Google Scholar
Zheng, X.-T., Bi, S.-D., Wang, X.-L., and Meng, J.. 2013. A new arboreal haramiyid shows the diversity of crown mammals in the Jurassic period. Nature 500:199–202.Google Scholar
Zhou, C.-F., Wu, S.-Y., Martin, T., and Luo, Z.-X.. 2013. A Jurassic mammaliaform and the earliest mammalian evolutionary adaptations. Nature 500:163–167.Google Scholar