Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-05T21:05:37.976Z Has data issue: false hasContentIssue false
  • English
  • Français

Does the Physiology of Large Living Reptiles Provide Insights into the Evolution of Endothermy and Paleophysiology of Extinct Dinosaurs?

Published online by Cambridge University Press:  26 July 2017

Frank V. Paladino  and
James R. Spotila
Frank V. Paladino
Affiliation:
Department of Biology, Indiana Purdue University at Fort Wayne, IN 46805-1499
James R. Spotila
Affiliation:
Department of Bioscience and Biotechnology, Drexel University, Philadelphia, PA. 19104
Get access

Abstract

Our studies using American alligators, Alligator mississippiensis, green turtles, Chelonia mydas, and leatherback turtles, Dermochelys coriacea, have provided insights into the physiology of large extant and extinct reptiles. Respiratory and metabolic physiology studies indicate that many living large reptiles exhibit heat conservation adaptations and mechanisms which allow them to maintain constant warm body temperatures in cold environments with low “reptilian” metabolism. For example, leatherback turtles which are found in the oceans as far north as the Arctic Circle can maintain constant body temperatures above 25° C while water temperatures are below 7° C. This dramatic ability to maintain warm temperatures in cold, highly conductive water, that would quickly cause hypothermia and kill most endotherms, is made possible by a mechanism we describe as gigantothermy. Gigantothermy is the ability to maintain constant warm body temperatures with low energy consumption, control of peripheral circulation and extensive insulation due to large body size.

The muscles of leatherbacks show a fiber type unlike the specialized, endothermic heater organs of modern fish Scombroidei (tunas, billfish, bonitos, butterfly mackerel and relatives) that have evolved specialized “endotherm like” red muscle to maintain regional endothermy. The primitive large reptiles like leatherbacks do not show the specialization in muscle fiber type nor do the enzyme activities indicate the emergence or evolution of endothermy or a high rate of energy consumption. Yet leatherbacks can migrate over 70 km per day in the open ocean and dive to depths deeper than 1000 m on a regular basis.

Collectively these physiological studies on large living reptiles support the concept that dinosaurs, especially the larger more spectacular species, were able to maintain high body temperatures, be very active, move great distances quickly, as well as exhibit complex behavior such as communal nesting and nest building without evolving endothermy or high levels of energy consumption. The physiology of large living reptiles indicates that it is not necessary to attribute heretical ideas to explain the paleophysiology and capabilities of dinosaurs. As reptiles they were fully capable of complex and spectacular behaviors such as long and rapid migrations and surviving the cold. All evolutionary indications suggest that large size would provide a negative selection pressure for the development of endothermy especially in equable and or tropical climates.

Type
Adaptations and Behavior
Information
The Paleontological Society Special Publications , Volume 7: Dino Fest , 1994 , pp. 261 - 274
Copyright
Copyright © 1994 Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bakker, R.T. 1986. The Dinosaur Heresies. William Morrow & CO, N.Y. 481 pGoogle Scholar
Barreto, C., Albrecht, R.M., Bjorling, D.E., Horner, J.R. & Wilsman, N.J. Evidence of the growth plate and the growth of long bones in juvenile dinosaurs. Science 262:2020–2023.CrossRefGoogle Scholar
Barrick, R. 1994. Thermal physiology of dinosaurs & oxygen isotopes. This volume.Google Scholar
Bennett, A.F. & Ruben, J. 1979. Endothermy and activity in vertebrates. Science 206:649–654.CrossRefGoogle ScholarPubMed
Bleakney, J. S. 1965. Reports of marine turtles from New England and eastern Canada. Can. Field-Nat. 79:120–128.CrossRefGoogle Scholar
Block, B.A. 1991. Evolutionary novelties: How fish have built a heater out of a muscle. Amer. Zool. 31:726–742.CrossRefGoogle Scholar
Block, B.A., Finnerty, J.R., Stewart, A.F.R. & Kidd, J. 1993. Evolution of endothermy in fish: Mapping physiological traits on a molecular phylogeny. Science 260:210–214.CrossRefGoogle ScholarPubMed
Brody, S. 1945. Bioenergetics and Growth Reinhold Pub. Co. N.Y. 724 pGoogle Scholar
Calder, W. A. 1984. Size, Function, and Life History. Harvard University Press, Cambridge, Mass. 431 p.Google Scholar
Carey, F.G. & Teal, J.M. 1969. Regulation of body temperature by the bluefin tuna. Comp. Biochem. Physiol. 28: 205–213.CrossRefGoogle ScholarPubMed
Carey, F.G., Teal, J.M., Kanwisher, J.W., Lawson, K.V. & Beckett, J.S. 1971. Warm-bodied fish. Amer. Zool. 11(1): 135–144.CrossRefGoogle Scholar
Carr, A. 1952. Handbook of Turtles. Cornell Univ. Press, Ithica, N.Y. 542 pGoogle Scholar
Chinsamy, A., Chiappe, L.M. & Dodson, P. 1994. Growth rings in Mesozoic birds. Nature 368:196–197 CrossRefGoogle Scholar
Chinsamy, A. 1990. Physiological implications of the bone histology of Syntarsus rhodesiensis (Saurischia: Theropoda) . Palaeont. afr. 27:77–82.Google Scholar
Dodson, P., Coombs, W. P., Farlow, J.O., & Tatarinov, L.P. 1990. Dinosaur Paleobiology. IN: The Dinosauria. Weishampel, D. P., Dodson, P., & Osmolska, H. EDS. pp 31–62. Univ of Calif. Press, Los Angeles, CA Google Scholar
Duron, M. D. 1978. Contribution a l'etude de la Biologie de Dermochelys coriacea (Linne) dans les Pertuis Charentais. Ph.D. Dissertation, University of Bordeaux, France.Google Scholar
Duron, M. and Duron, P. 1980. Des tortues luths dans les Pertuis Charentais. Courrier Nat. 69:37–41.Google Scholar
Farlow, J.O. 1993. On the rareness of big fierce animals: speculations about the body sizes, population densities, and geographic ranges of predatory mammals and large carnivorous dinosaurs. Amer. J. Sci. 293-A:167–199.Google Scholar
Folger, T. 1993. The Blood of the Dinos. Discover Magazine Special Issue 1993 “A Journey Into Life” pp 18–19.Google Scholar
Friar, W., Ackman, R. G., and Mrosovsky, N. 1972. Body temperature of Dermochelys coriacea a warm turtle from cold water. Science 177: 791–793.CrossRefGoogle Scholar
Haines, R.W. 1941. Epiphyseal structure in lizards and marsupials. J. Anat. 75:282–294 Google ScholarPubMed
Haines, R.W. 1942. The evolution of epiphyses and of endochondral bone. Biol. Rev. 17:267–292.CrossRefGoogle Scholar
Haines, R.W. 1969. Epiphyses and Sesamoids. IN: Biology of The Reptilia Volume I, Gans, C. Ed, pp 81–115. Academic Press, N.Y. Google Scholar
Hammer, W.R., Collinson, J.R. & Ryan, W. J. 1990. A new Triassic vertebrate fauna from Antarctica and its depositional setting. Antarctic Sci. 2(2):163–167.CrossRefGoogle Scholar
Horner, J.R. 1984. The nesting behavior of Dinosaurs. Scient. Amer. 250(4):130–137.CrossRefGoogle Scholar
Kleiber, M. 1964. The Fire of Life. John Wiley & Sons, INC. New York 453 pGoogle Scholar
Kolodny, Y. & Luz, B. 1993. Dinosaur thermal physiology from dO18 in bone phosphate; is it possible? In: Second Oxford Workshop on Bone Diagenesis. June 1993. Abstracts. Oxford University, England.Google Scholar
Mrosovsky, N. and Pritchard, P.C.H. 1971. Body temperatures of Dermochelys coriacea and other sea turtles. Copeia 1971: 624–631.CrossRefGoogle Scholar
Paladino, F.V., O'Connor, M.P. & Spotila, J.R. 1990. Metabolism of leatherback turtles. gigantothermy and thermoregulation of dinosaurs. NATURE 344:858–860 CrossRefGoogle Scholar
Pennick, D.N., Paladino, F. V., Steyermark, A.S., & Spotila, J.R. 1994. Thermal independence of tissue metabolism in the Leatherback turtle (Dermochelys coriacea). Manuscript in Review.Google Scholar
Reid, R.E.H. 1990. Zonal “Growth rings” in dinosaurs. Modern Geol. 15:19–48.Google Scholar
Rich, P.V. & Rich, T.H. 1993. Australia's Polar Dinosaurs. Scient. Amer. July 50-55.CrossRefGoogle Scholar
Ruben, J. 1991. Reptilian physiology and the flight capacity of Archaeopteryx . Evol. 45(1):1–17.CrossRefGoogle ScholarPubMed
Spotila, J.R., and Gates, D.M. 1975. Body Size, Insulation and Optimum Body Temperatures of Homeotherms. In: Gates, D.M. (ed.), Biophysical Ecology, Chapter 17, pp. 291–301. Springler Verlag, New York.Google Scholar
Spotila, J.R., O'Connor, M.P., Dodson, P., Paladino, F.V. 1991. Hot and cold running dinosaurs:body size, metabolism and migration. Modern Geol. 16:203–227.Google Scholar
Spotila, J.R. and Standora, E.A. 1985. Environmental constraints on the thermal energetics of sea turtles. Copeia 1985: 694–702.CrossRefGoogle Scholar
Spotila, J.R., Soule, O.H., and Gates, D.M. 1972. The biophysical ecology of the alligator: Heat energy budgets and climate spaces. Ecology 53:1094–1102.CrossRefGoogle Scholar
Spotila, J.R., Lommen, P.W., Bakken, G.S., and Gates, D. M. 1973. A mathematical model for body temperatures of large reptiles: implications for dinosaur ecology. Amer. Natur. 107: 391–404.CrossRefGoogle Scholar
Standora, E.A., Spotila, J.R., Keinath, J.A., and Schoop, R.C. 1984. Movement, diving cycles and body temperatures of a free-swimming juvenile leatherback turtle, Dermochelys coriacea . Herpetologica 40: 169–176.Google Scholar
Terpin, K.M., Spotila, J.R., and Foley, R.E. 1979. Thermoregulatory adaptations and heat energy budget analyses of the American alligator, Alligator mississippiensis . Physiol. Zool. 52: 296–312.CrossRefGoogle Scholar
Willgohs, J. F. 1957. Occurrence of the leathery turtle in the northern North Sea and off western Norway. Nature 179:163–164.CrossRefGoogle Scholar