Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-26T18:01:45.434Z Has data issue: false hasContentIssue false

Comparison of water vapor conductance in a titanosaur egg from the Upper Cretaceous of Argentina and a Megaloolithus siruguei egg from Spain

Published online by Cambridge University Press:  08 April 2016

Frankie D. Jackson
Affiliation:
Department of Earth Sciences, Montana State University, Bozeman, Montana 59717. E-mail: [email protected]
David J. Varricchio
Affiliation:
Department of Earth Sciences, Montana State University, Bozeman, Montana 59717. E-mail: [email protected]
Robert A. Jackson
Affiliation:
Department of Earth Sciences, Montana State University, Bozeman, Montana 59717. E-mail: [email protected]
Bernat Vila
Affiliation:
Institut Català de Paleontologia, Carrer Escola Industrial 23, 08201 Sabadell, Barcelona, Spain
Luis M. Chiappe
Affiliation:
Department of Vertebrate Paleontology, Natural History Museum of Los Angeles County, Los Angeles, California 90007

Abstract

We calculated water vapor conductance (a product of eggshell porosity) from the first definitively identified sauropod egg (Megaloolithus patagonicus) from the Auca Mahuevo locality in Argentina. We then compared the results with those from M. siruguei (an egg type long associated with sauropod dinosaurs) from the Pinyes locality in Spain. The 14-cm Auca Mahuevo egg has a thinner eggshell and 47 times fewer pores than the 22-cm M. siruguei specimen. The resulting water vapor conductance (GH2O) of the titanosaur and M. siruguei eggs is 341 and 3979 mg H2O day−1 Torr−1, respectively; these values are two and ten times greater than in avian eggs of comparable size, but lower than in eggs of most modern reptiles. Clutches from Auca Mahuevo typically contain 20–40 eggs; in contrast, M. siruguei clutches from the Pinyes site average nine eggs. The GH2O of M. siruguei exceeds that of the Argentine egg by an order of magnitude, supporting previous inferences of egg burial. The GH2O of the Argentine titanosaur egg closely approximates that of Troodon and some oviraptorid eggs, previously calculated as equal to or two times greater than, respectively, the GH2O of avian eggs of similar size. Higher embryonic growth rates (relative to modern reptiles), especially in some dinosaurs with large clutch mass, may have required incubation in a more open environment, where water conservation represented a more critical factor than in a buried clutch. The lower GH2O calculated for the two megaloolithid eggs is consistent with previous interpretations of nesting mode that are based on site taphonomy and nesting traces. This study indicates that at least some dinosaurs did not fully bury their eggs.

Type
Articles
Copyright
Copyright © The 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

Literature Cited

Ackerman, R. A. 1980. Physiological and ecological aspects of gas exchange by sea turtle eggs. American Zoologist 20:575583.Google Scholar
Ardèvol, L., Vicens, E., Capdevila, J., and López-Martínez, N. 1999. Field trip guide of the first symposium on dinosaur eggs and babies, Abstracts 18.Google Scholar
Ardèvol, L., Klimowitz, J., Malagón, J., and Nagtegaal, P. 2000. Depositional sequence response to foreland deformation in Upper Cretaceous of the southern Pyrenees, Spain. AAPG Bulletin 84:566587.Google Scholar
Ar, A., and Rahn, H. 1978. Interdependence of gas conductance, incubation length and weight of the avian egg. Pp. 153158 in Piiper, J. Respiratory function in birds, adult and embryonic. Springer, Heidelberg.Google Scholar
Ar, A., and Rahn, H. 1985. Pores in avian eggshells: gas conductance, gas exchange, and embryonic growth rate. Respiration Physiology 61:120.Google Scholar
Ar, A., Paganelli, C. V., Reeves, R. B., Greene, D. G., and Rahn, H. 1974. The avian egg: water vapor conductance, shell thickness, and functional pore area. Condor 76:153158.Google Scholar
Birkeland, P. W. 1999. Soils and geomorphology. Oxford University Press, New York.Google Scholar
Booth, D. T., and Thompson, M. B. 1991. A comparison of reptilian eggs with those of megapode birds. Pp. 325344 in Deeming, D. C. and Ferguson, M. W. J., eds. Egg incubation: its effects on embryonic development in birds and reptiles. Cambridge University Press, Cambridge.Google Scholar
Brady, N. C., and Weil, R. R. 2002. The nature and properties of soils. Prentice Hall, Upper Saddle River, N.J. Google Scholar
Bravo, A. M., and Reyes, T., eds. 1999. Extended abstracts. First international symposium on dinosaur eggs and babies, Isona, Spain, 23–26 September 1999.Google Scholar
Bravo, A. M., Moratalla, J. J., Santafé, J. V., and Santisteban, C. D. 1999. Faidella, a new Upper Cretaceous nesting site from the Tremp Basin (Lérida Province, Spain). Pp. 95115 in Bravo, and Reyes, 1999.Google Scholar
Burbidge, A. A., and Kuchling, G. 2004. Western Swamp Tortoise (Pseudemydura umbrina) recovery plan, 3d ed., January 2003–December 2007. Department of Conservation and Land Management, Wanneroo, Australia.Google Scholar
Calvo, J. O., Engelland, S., Heredia, S. E., and Salgado, L. 1997. First record of dinosaur eggshells (? Sauropoda-Megaloolithidae) from Neuquén, Patagonia, Argentina. Gaia 14:2332.Google Scholar
Carpenter, K. 1999. Eggs, nests, and baby dinosaurs: a look at dinosaur reproduction. Indiana University Press, Bloomington.Google Scholar
Carpenter, K., Hirsch, K. F., and Horner, J. R., eds. 1994. Dinosaur eggs and babies. Cambridge University Press, Cambridge.Google Scholar
Case, T. J. 1978. Speculations on the growth rate and reproduction of some dinosaurs. Paleobiology 4:320328.Google Scholar
Castanet, J., Grandin, A., Arbourachid, A., and Ricqlès, A. 1996. Expression de la dynamique de croissance dans la structure de l'os periostique chez Anas platyrhynchous . Comptes Rendus de l'Académie des Sciences de Paris, série III, Science de la Vie 319:301308.Google Scholar
Castanet, J., Curry-Rogers, K., Cubo, J., and Boisard, J. J. 2000. Quantification of periosteal osteogenesis in ostrich and emu: implications for assessing growth in dinosaurs. Comptes Rendus de l'Académie des Sciences de Paris, série III, Science de la Vie 323:543550.Google Scholar
Chiappe, L. M., Coria, R. A., Dingus, L., Jackson, F., Chinsamy, A., and Fox, M. 1998. Sauropod dinosaur embryos from the Late Cretaceous of Patagonia. Nature 396:258261.Google Scholar
Chiappe, L. M., Dingus, L., Jackson, F., Grellet-Tinner, G., Aspinall, R., Clarke, J., Coria, R., Garrido, A., and Loope, D. 1999. Sauropod eggs and embryos from the Upper Cretaceous of Patagonia. Pp. 2329 in Bravo, and Reyes, 1999.Google Scholar
Chiappe, L. M., Salgado, L., and Coria, R. A. 2001. Embryonic skulls of titanosaur sauropod dinosaurs. Science 293:24442446.Google Scholar
Chiappe, L. M., Coria, R. A., Jackson, F., and Dingus, L. 2003. The Late Cretaceous nesting site of Auca Mahuevo (Patagonia, Argentina): eggs, nests, and embryos of titanosaurian sauropods. Palaeovertebrata 32(2–5):97108.Google Scholar
Chiappe, L. M., Schmitt, J. G., Jackson, F., Garrido, A., Dingus, L., and Grellet-Tinner, G. 2004. Nest structure for sauropods: sedimentary criteria for recognition of dinosaur nesting traces. Palaios 19:8995.2.0.CO;2>CrossRefGoogle Scholar
Chiappe, L. M., Jackson, F., Coria, R. A., and Dingus, L. 2005. Nesting titanosaurs from Auca Mahuevo and adjacent sites. Pp. 285302 in Curry-Rogers, K. and Wilson, J., eds. The sauropods. University of California Press, Berkeley.Google Scholar
Clark, J. M., Norell, M. A., and Chiappe, L. M. 1999. An oviraptorid skeleton from the Late Cretaceous of Ukhaa Tolgod, Mongolia, preserved in an avianlike brooding position over an oviraptorid nest. American Museum Novitates 3265:136.Google Scholar
Cousin, R., and Breton, G. 1999. A precise and complete excavation is necessary to demonstrate a dinosaur clutch structure. Pp. 3141 in Bravo, and Reyes, 1999.Google Scholar
Cousin, R., Breton, G., Fournier, R., and Watté, J.-P. 1994. Dinosaur egg-laying and nesting in France. Pp. 5674 in Carpenter, et al. 1994.Google Scholar
Curry-Rogers, K., and Erickson, G. M. 2005. Sauropod histology. Pp. 303326 in Curry-Rogers, K. and Wilson, J., eds. The sauropods. University of California Press, Berkeley.Google Scholar
Davies, S. J. J. F. 2002. Ratites and tinamous. Oxford University Press, Oxford.Google Scholar
Deeming, D. C. 2002. Importance and evolution of incubation in avian reproduction. Pp. 17 in Deeming, D. C., ed. Avian incubation: behaviour, environment and evolution. Oxford University Press, Oxford.Google Scholar
Deeming, D. C. 2006. Ultrastructural and functional morphology of eggshells supports the idea that dinosaur eggs were incubated buried in a substrate. Palaeontology 49:171185.Google Scholar
Deeming, D. C., and Ferguson, M. W. J., eds. 1991. Avian incubation: behaviour, environment and evolution. Oxford University Press, Oxford.Google Scholar
Deeming, D. C., and Thompson, M. B. 1991. Gas exchange across reptilian eggshells. Pp. 277284 in Deeming, and Ferguson, 1991.Google Scholar
Dong, Z.-M., and Currie, P. J. 1996. On the discovery of an oviraptorid skeleton on a nest of eggs at Bayan Mandahu, Inner Mongolia, People's Republic of China. Canadian Journal of Earth Sciences 33:631636.Google Scholar
Dunson, W. A. 1982. Low water vapor conductance of hard-shelled eggs of the gecko lizards Hemidactylus and Lepidodactylus . Journal of Experimental Zoology 219:377379.Google Scholar
Dunson, W. A., and Bramham, C. R. 1981. Evaporative water loss and oxygen consumption of three small lizards from the Florida Keys: Spanerodactylus cinereus, S. notatus, and Anolis sagrei . Physiological Zoology 54:253259.CrossRefGoogle Scholar
Epperson, D. M., and Heis, C. D. 2005. Nesting and hatchling ecology of gopher tortoises (Gopherus polyphemus) in southern Mississippi. Journal of Herpetology 37:315324.Google Scholar
Erickson, G. 2005. Assessing dinosaur growth patterns: a microscopic revolution. Trends in Ecology and Evolution 20:677684.Google Scholar
Ferguson, M. W. J. 1982. The structure and composition of the eggshell and embryonic membranes of Alligator mississippiensis . Transactions of the Zoological Society of London, 36:99152.Google Scholar
Galbrun, B., Feist, M., Colombo, F., Rocchia, R., and Tambareau, Y. 1993. Magnetostratigraphic and biostratigraphy of Cretaceous-Tertiary continental deposits, Ager basin, province of Lérida, Spain. Palaeogeography, Palaeoclimatology, Palaeoecology, 102:4152.Google Scholar
Garcia, G., Dutour, Y., Cojan, I., Valentin, X., and Cheylan, G. 2003. Long-term fidelity of megaloolithid egg-layers to a large breeding-ground in the Upper Cretaceous of Aix-en-Provence (southern France). Palaeovertebrata, 32(2–4):109120.Google Scholar
Geist, N. R., and Jones, T. 1996. Juvenile skeletal structure and the reproductive habits of dinosaurs. Science 272:712714.Google Scholar
Grellet-Tinner, G., and Chiappe, L. M. 2004. Dinosaur eggs and nesting: implications for understanding the origin of birds. Pp. 185214 in Currie, P. J., Koppelhus, E. B., Shugar, M. A., and Wright, J. L., eds. Feathered dragons: studies on the transition from dinosaurs to birds. Indiana University Press, Bloomington.Google Scholar
Grellet-Tinner, G., Chiappe, L. M., and Coria, R. 2004. Eggs of titanosaur sauropods from the Upper Cretaceous of Auca Mahuevo (Argentina). Canadian Journal of Earth Sciences 41:949960.Google Scholar
Grellet-Tinner, G., Chiappe, L. M., Norell, M., and Bottjer, D. 2006. Dinosaur eggs and nesting ecology: a paleobiological investigation. Palaeogeography, Palaeoclimatology, Palaeoecology 232:294321.Google Scholar
Grigg, G. C., and Beard, L. 1985. Water loss and gain by eggs of Crocodylus porosus, related to incubation age and fertility. Pp. 353359 in Grigg, G., Shine, R., and Ehmann, H., eds. Biology of Australasian frogs and reptiles. Surry Beatty, Sydney.Google Scholar
Grigorescu, D., Weishampel, D., Norman, D., Seclamen, M., Rusu, M., Baltres, A., and Teodorescu, V. 1994. Late Maastrichtian dinosaur eggs from the Hateg Basin (Romania). Pp. 7587 in Carpenter, et al. 1994.Google Scholar
Harrison, K. E., Bently, T. B., Lutz, P. L., and Marszalek, D. S. 1978. Water and gas diffusion in the American crocodile egg. American Zoologist. 18:637.Google Scholar
Hirsch, K. F. 2001. Pathological amniote eggshell—fossil and modern. Pp. 378392 in Tanke, D. H. and Carpenter, K., eds. Mesozoic vertebrate life. Indiana University Press, Bloomington.Google Scholar
Horne, B. D., Brauman, R. J., Moore, M. J. C., and Seigel, R. A. 2003. Reproductive and nesting ecology of the yellow-blotched map turtle Graptemys flavimaculata: implications for conservation and management. Copeia 4:729738.Google Scholar
Horner, J. R. 1984. The nesting behavior of dinosaurs. Scientific American 250:130137.Google Scholar
Horner, J. R., and Makela, R. 1979. Nest of juveniles provides evidence of family structure among dinosaurs. Nature 282:296298.Google Scholar
Horner, J. R., Ricqlès, A., and Padian, K. 2000. Long bone histology of the hadrosaurid Maiasaura peeblesorum: growth dynamics and physiology based on an ontogenetic series of skeletal elements. Journal of Vertebrate Paleontology 20:109123.Google Scholar
Jackson, F. 2007. Titanosaur reproductive biology: comparison of the Auca Mahuevo titanosaur nesting locality (Argentina), to the Pinyes Megaloolithus nesting locality (Spain). . Montana State University, Bozeman.Google Scholar
Jackson, F. D., and Varricchio, D. J. 2003. Abnormal, multilayered eggshell in birds: implications for dinosaur reproductive anatomy. Journal of Vertebrate Paleontology 23:699702.Google Scholar
Jackson, F. D., Garrido, A., Schmitt, J. G., Chiappe, L., Dingus, L., and Loope, D. 2004. Abnormal, multilayered titanosaur (Dinosauria: Sauropoda) eggs from in situ clutches at the Auca Mahuevo locality, Neuquén Province, Argentina. Journal of Vertebrate Paleontology 24:913922.Google Scholar
Kern, M. D., and Ferguson, M. W. J. 1997. Gas permeability of American alligator eggs and its anatomical basis. Physiological Zoology 70:530546.Google Scholar
Kérourio, P. 1981. La distribution des “Coquilles d'oeufs de Dinosauriens multistratifiees” dans le Maestrichtien continental du Sud de la France. Geobios 14:533536.Google Scholar
Kohring, R., 1989. Fossile Eierschalen aus dem Garumnium (Maastrichtium) von Bastus (Provinz Lleida, NE-Spanien). Berliner Geowiss Abhandlungen, Reihe A 106:267275.Google Scholar
Long, J. A., Vickers-Rich, P., Hirsch, K., Bray, E., and Tuniz, C. 1998. The Cervantes egg: an early Malagasy tourist to Australia. Records of the Western Australian Museum 19:3946.Google Scholar
Loope, D., Schmitt, J. G., and Jackson, F. 2000. Thunder platters: thin discontinuous limestones in Late Cretaceous continental mudstones of Argentina may be chemically infilled sauropod tracks. Geological Society of America Abstracts with Programs 32:A450.Google Scholar
López-Martínez, N. 1999. Eggshell sites from the Cretaceous-Tertiary transition in south central Pyrenees (Spain). Pp. 95115 in Bravo, and Reyes, 1999.Google Scholar
López-Martínez, N., Moratalla, J. J., and Sanz, J. L. 2000. Dinosaurs nesting on tidal flats. Palaeogeography, Palaeoclimatology, Palaeoecology 160:153163.Google Scholar
López-Martínez, N., Canudo, J. I., Ardèvol, L., Pereda-Suberbiola, X., Orue-Etxebarria, X., Cuenca-Bescós, G., Ruíz-Omeñaca, J. I., Murelaga, X., and Feist, M. 2001. New dinosaur sites correlated with Upper Maastrichtian pelagic deposits in the Spanish Pyrenees: implications for the dinosaur extinction pattern in Europe. Cretaceous Research 22:4161.Google Scholar
Lutz, P. L., Bentley, T. B., Harrison, K. E., and Marszalek, D. S. 1980. Oxygen and water vapor conductance in the shell and shell membrane of the American crocodile egg. Comparative Biochemistry and Physiology A 66:335338.Google Scholar
Mayoral, E., and Calzada, S. 1998. Reinterpretación de Spirographites ellipticus Astre, 1937 como pista fósil de artrópodos no marinos del Cretácico superior (Facies Garumn) del Pirineo catalán (NE de España). Geobios 31:633643.Google Scholar
Mikhailov, K. E. 1997. Fossil and recent eggshell in amniotic vertebrates: fine structure, comparative morphology and classification. Special Papers in Palaeontology 56:180.Google Scholar
Mohabey, D. M. 1996. A new oospecies, Megaloolithus matleyi, from the Lameta Formation (Upper Cretaceous) of Chandrapur district, Maharashtra, India, and general remarks on the paleoenvironment and nesting behavior of dinosaurs. Cretaceous Research 17:183196.Google Scholar
Mohabey, D. M. 1999. Indian Upper Cretaceous (Maestrichtian) dinosaur eggs: their parataxonomy and implications in understanding the nesting behaviour. Pp. 139153 in Bravo, and Reyes, 1999.Google Scholar
Mohabey, D. M. 2001. Indian dinosaur eggs: a review. Journal of the Geological Society of India 58:479508.Google Scholar
Mueller-Töwe, I. J., Sander, P. M., Schuller, H., and Thies, D. 2002. Hatching and infilling of dinosaur eggs as revealed by computed tomography. Palaeontographica A 267:168.Google Scholar
Norell, M. A., Clark, J. M., Chiappe, L. M., and Dashzeveg, D. 1995. A nesting dinosaur. Nature 378: 884–776.Google Scholar
Packard, G. C., Taigen, T. L., Packard, M. J., and Shuman, R. D. 1979. Water-vapor conductance of testudinian and crocodilian eggs (Class Reptilia). Respiration Physiology 38:110.Google Scholar
Padian, K., Horner, J. R., and Ricqlès, A. de. 2004. Little dinosaurs and pterosaurs: the evolution of archosaurian growth strategies. Journal of Vertebrate Paleontology 24:555571.Google Scholar
Peitz, C. 1999. Parataxonomic implications of some megaloolithid dinosaur eggs from Catalunya, Spain. Pp. 4950 in Bravo, and Reyes, 1999.Google Scholar
Peitz, C. 2000. Megaloolithid dinosaur eggs from the Maastrichtian of Catalunya (NE-Spain): Parataxonomic implications and stratigraphic utility. Pp. 155159 in Bravo, and Reyes, 1999.Google Scholar
Retallack, G. J. 1990. Soils of the past. Unwin Hyman, Boston.Google Scholar
Richlefs, R. E., and Stark, J. M. 1998. Embryonic growth and development. Pp. 3158 in Richlefs, R. E. and Stark, J. M., eds. Avian growth and development. Oxford University Press, Oxford.Google Scholar
Ricqlès, A. de. 1983. Cyclical growth in the long limb bones of a sauropod dinosaur. Acta Palaeontologica Polonica 28:225232.Google Scholar
Ricqlès, A. de., Meunier, F. J., Castanet, J., and Francillon-Vieillot, H. 1991. Comparative microstructure of bone. Pp. 178 in Hall, B. K., ed. Bone, bone matrix, and bone specific products. CRC Press, Boca Raton, Fla. Google Scholar
Ruben, J. A., Hillenius, W. J., Geist, N. R., Leitch, A., Jones, T. D., Currie, P. J., Horner, J. R., and Espe, G. III. 1996. The metabolic status of some Late Cretaceous dinosaurs. Science 273:12041207.Google Scholar
Sabath, K. 1991. Upper Cretaceous amniotic eggs from the Gobi Desert. Acta Palaeontologica Polonica 36:151192.Google Scholar
Sahni, A., and Khosla, A. 1994. Paleobiological, taphonomical and paleoenvironmental aspects of Indian Cretaceous sauropod nesting sites. Gaia 10:215223.Google Scholar
Sahni, A., Tandon, S., Jolly, A., Bajpai, S., Sood, A., and Srinivasan, S. 1994. Upper Cretaceous dinosaur eggs and nesting sites from the Deccan volcano-sedimentary province of peninsular India. Pp. 204226 in Carpenter, et al. 1994.Google Scholar
Sander, P. M. 2000. Long bone histology of the Tendaguru sauropods: implications for growth and biology. Paleobiology 26:466488.Google Scholar
Sander, P. M., Peitz, C., Gallemí, J., and Cousin, R. 1998. Dinosaurs nesting on a red beach? Comptes Rendus de l'Académie des Sciences de Paris, série II, Sciences de la Terre et des Planètes 327:6774.Google Scholar
Sander, P. M., Klein, N., Buffetaut, E., Cuny, G., Suteethorn, V., and Le Loeuff, J. 2004. Adaptive radiation in sauropod dinosaurs: bone histology indicates rapid evolution of giant body size through acceleration. Organisms, Diversity and Evolution 4:165173.Google Scholar
Sander, P. M., Peitz, C., Jackson, F., and Chiappe, L. In press. Upper Cretaceous titanosaur nesting sites and their implications for sauropod dinosaur reproductive biology. Palaeontographica, Abteilung A.Google Scholar
Sanz, J. L., and Moratalla, J. J. 1997. Bastús nesting site. Pp. 4243 in Currie, P. J. and Padian, K., eds. Encyclopedia of dinosaurs. Academic Press, San Diego.Google Scholar
Scotese, C. R. 2000. Paleomap project. http://www.scotise.com/climate.htm.Google Scholar
Seymour, R. S. 1979. Dinosaur eggs: gas conductance through the shell, water loss during incubation, and clutch size. Palaeobiology 5:111.Google Scholar
Seymour, R. S., and Ackerman, R. A. 1980. Adaptations to underground nesting in birds and reptiles. American Zoologist 20:437447.Google Scholar
Thompson, M. B. 1985. Functional significance of the opaque white patch in eggs of Emydura macquarii. Pp. 387395 in Grigg, G., Shine, R., and Ehmann, H., eds. Biology of Australian frogs and reptiles. Royal Zoological Society, New South Wales, Sydney.Google Scholar
Varricchio, D. J., and Jackson, F. D. 2004. Origins of avian reproduction: answers and questions from dinosaurs. Palaeovertebrata 32:7795.Google Scholar
Varricchio, D. J., Jackson, F., Borkowski, J., and Horner, J. R. 1997. Nest and egg clutches of the dinosaur Troodon formosus and the evolution of avian reproductive traits. Nature 385:247250.Google Scholar
Varricchio, D. J., Jackson, F., and Truman, C. 1999. A nesting trace with eggs for the Cretaceous theropod dinosaur Troodon formosus . Journal of Vertebrate Paleontology 19:91100.Google Scholar
Vianey-Liaud, M., Mallan, P., Buscail, O., and Montgelard, C. 1994. Review of French dinosaur eggshells: morphology, structure, mineral, and organic composition. Pp. 151183 in Carpenter, et al. 1994.Google Scholar
Vianey-Liaud, M., Khosla, A., and Garcia, G. 2003. Comparison of European and Indian dinosaur eggshells: paleobiogeographical implications. Journal of Vertebrate Paleontology 23:575585.Google Scholar
Vleck, C. M., and Hoyt, D. F. 1991. Metabolism and energetics of reptilian and avian embryos. Pp. 285307 in Deeming, and Ferguson, 1991.Google Scholar
Weishampel, D. B., and Horner, J. R. 1994. Life history syndromes, heterochrony, and the evolution of Dinosauria. Pp. 229243 in Carpenter, et al. 1994.Google Scholar
Weishampel, D. B., Barrett, P. M., Coria, R. A., Loeuff, J. L., Zing, X., Xijin, Z., Sahni, A., Gomani, E. M. P., Noto, C. R. 2004. Dinosaur distribution. Pp. 525 in Weishampel, D. B., Dodson, P., and Osmólska, H., eds. The Dinosauria. University of California Press, Berkeley.Google Scholar
Williams, D. L. G., Seymour, R. S., and Kerourio, P., 1984. Structure of fossil dinosaur eggshell from the Aix Basin, France. Palaeogeography, Palaeoclimatology, Palaeoecology 45:2337.Google Scholar
Wink, C. S., Elsey, R. M., and Bouvier, M. 1990. The relationship of pores and mammillae on the inner surface of the eggshell of the alligator (Alligator mississippiensis). Journal of Morphology 204:227233.Google Scholar