Hostname: page-component-594f858ff7-7tp2g Total loading time: 0 Render date: 2023-06-07T07:10:10.350Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": false, "coreDisableEcommerce": false, "corePageComponentUseShareaholicInsteadOfAddThis": true, "coreDisableSocialShare": false, "useRatesEcommerce": true } hasContentIssue false

The evolution of growth patterns in mammalian versus nonmammalian cynodonts

Published online by Cambridge University Press:  28 April 2016

Rachel N. O’Meara
University Museum of Zoology, Downing Street, Cambridge, CB2 3EJ, United Kingdom. E-mail:
Robert J. Asher
University Museum of Zoology, Downing Street, Cambridge, CB2 3EJ, United Kingdom. E-mail:


One of the major evolutionary transitions of the mammaliaform lineage was the origin of a typically mammalian pattern of growth. This is characterized by rapid juvenile growth followed by abrupt cessation of growth at adult size and may be linked with other important mammaliaform apomorphies of dental replacement and morphology. Investigation of growth patterns in the tritylodontid cynodont Oligokyphus and the basal mammaliaform Morganucodon provides insight into this crucial transition. We collected mandibular depth measurements from large samples of Morganucodon and Oligokyphus and constructed distributions of mandibular depth versus frequency for each species. These were compared with distributions from species from three different growth classes of extant amniote: testudines + crocodilians, mammals + birds, and lepidosaurs. Discriminant function analysis was used to differentiate between known growth classes by using different combinations of three measures of mandibular depth distribution shape (skew, kurtosis, and coefficient of variation) as proxies for different juvenile and adult growth patterns. Classification of the fossil species showed that Morganucodon closely resembled extant placental mammals in having rapid juvenile growth followed by truncated, determinate adult growth. Oligokyphus showed intermediate growth patterns, with more extended adult growth patterns than Morganucodon and slightly slower juvenile growth. This suggests a gradual evolution of mammalian growth patterns across the cynodont to mammaliaform transition, possibly with the origin of rapid juvenile growth preceding that of truncated, determinate adult growth. In turn, acquisition of both these aspects of mammalian growth was likely necessary for the evolution of diphyodont tooth replacement in the mammaliaform lineage.

Copyright © 2016 The Paleontological Society. All rights reserved 

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.)


Literature Cited

Abdala, F., Jasinoski, S. C., and Fernandez, V.. 2013. Ontogeny of the Early Triassic cynodont Thrinaxodon liorhinus (Therapsida): dental morphology and replacement. Journal of Vertebrate Paleontology 33:14081431.CrossRefGoogle Scholar
Adolph, S. C., and Porter, W. P.. 1996. Growth, seasonality, and lizard life histories: age and size at maturity. Oikos 77:267278.CrossRefGoogle Scholar
Andrews, R. M. 1982. Patterns of growth in reptiles. Pp. 273320 in C. Gans, and F. H. Pough, eds. Biology of the Reptilia, Vol. 13. Academic, New York.Google Scholar
Asher, R. J., and Lehmann, T.. 2008. Dental eruption in afrotherian mammals. BMC Biology 6:14.CrossRefGoogle ScholarPubMed
Asher, R. J., and Olbricht, G.. 2009. Dental ontogeny in Macroscelides proboscideus (Afrotheria) and Erinaceus europaeus (Lipotyphla). Journal of Mammalian Evolution 16:99115.CrossRefGoogle Scholar
Balazs, G. H. 1980. Synopsis of biological data on the green turtle in the Hawaiian islands. NOAA Technical Memorandum NMFS, NOAA-SWFC-7. U.S. Department of Commerce.Google Scholar
Barr, W. A., and Scott, R. S.. 2014. Phylogenetic comparative methods complement discriminant function analysis in ecomorphology. American Journal of Physical Anthropology 153:663674.CrossRefGoogle ScholarPubMed
Benjamini, Y., and Hochberg, Y.. 1995. Controlling the false discovery rate: a practical and powerful approach to multiple testing. Journal of the Royal Statistical Society B 57:289300.Google Scholar
Bjorndal, K. A., Parsons, J., Mustin, W., and Bolten, A. B.. 2013. Threshold to maturity in a long-lived reptile: interactions of age, size, and growth. Marine Biology 160:607616.CrossRefGoogle Scholar
Botha, J., and Chinsamy, A.. 2000. Growth patterns deduced from the histology of the cynodonts Diademodon and Cynognathus. Journal of Vertebrate Paleontology 20:705711.CrossRefGoogle Scholar
Botha, J., and Chinsamy, A.. 2005. Growth patterns of Thrinaxodon liorhinus, a non-mammalian cynodont from the Lower Triassic of South Africa. Palaeontology 48:385394.CrossRefGoogle Scholar
Botha-Brink, J., Abdala, F., and Chinsamy-Turan, A.. 2012. The radiation and osteohistology of nonmammaliaform cynodonts. Pp. 222246 in A. Chinsamy-Turan, ed. Forerunners of mammals: radiation, histology, biology. Indiana University Press, Bloomington.Google Scholar
Butler, E. 2010. The post-cranial skeleton of the Early Triassic non-mammalian cynodont Galesaurus planiceps: implications for biology and lifestyle. Master’s dissertation, University of the Free State, Bloemfontein, South Africa.Google Scholar
Butler, P. M. 1995. Ontogenetic aspects of dental evolution. International Journal of Developmental Biology 39:2534.Google ScholarPubMed
Carr, A., and Goodman, D.. 1970. Ecologic implications of size and growth in Chelonia. Copeia 4:783786.CrossRefGoogle Scholar
Case, T. J. 1978. On the evolution and adaptive significance of postnatal growth rates in the terrestrial vertebrates. Quarterly Review of Biology 53:243282.CrossRefGoogle ScholarPubMed
Castanet, J., and Báez, M.. 1991. Adaptation and evolution in Gallotia lizards from the Canary Islands: age, growth, maturity and longevity. Amphibia-Reptilia 12:81102.CrossRefGoogle Scholar
Castanet, J., Newman, D. G., and Saint Girons, H.. 1988. Skeletochronological data on the growth, age and population structure of the tuatara, Sphenodon punctatus, on the Stephens and Lady Alice islands, New Zealand. Herpetologica 44:2537.Google Scholar
Charnov, E. L., Turner, T. F., and Winemiller, K. O.. 2001. Reproductive constraints and the evolution of life histories with indeterminate growth. Proceedings of the National Academy of Sciences USA 98:94609464.CrossRefGoogle ScholarPubMed
Chen, M., and Wilson, G. P.. 2015. A multivariate approach to infer locomotor modes in Mesozoic mammals. Paleobiology 41:280312.CrossRefGoogle Scholar
Chiari, Y., Cahais, V., Galtier, N., and Delsuc, F.. 2012. Phylogenomic analyses support the position of turtles as the sister group of birds and crocodiles (Archosauria). BMC Biology 10:65.CrossRefGoogle Scholar
Chinsamy, A., and Abdala, F.. 2008. Palaeobiological implications of the bone microstructure of South American traversodontids (Therapsida: Cynodontia). South African Journal of Science 104:225230.Google Scholar
Chinsamy, A., and Hurum, J. H.. 2006. Bone microstructure and growth patterns of early mammals. Acta Palaeontologica Polonica 51:325338.Google Scholar
Chinsamy, A., Hanrahan, S. A., Neto, R. M., and Seely, M.. 1995. Skeletochronological assessment of age in Angolosaurus skoogi, a cordylid lizard living in an aseasonal environment. Journal of Herpetology 29:457460.CrossRefGoogle Scholar
Ciancio, M. R., Castro, M. C., Galliari, F. C., Carlini, A. A., and Asher, R. J.. 2012. Evolutionary implications of dental eruption in Dasypus (Xenarthra). Journal of Mammalian Evolution 19:18.CrossRefGoogle Scholar
Clemens, W. A. 1979. A problem in morganucodontid taxonomy. Zoological Journal of the Linnean Society 66:114.CrossRefGoogle Scholar
Comrey, A. L., and Lee, H. B.. 1992. A first course in factor analysis, 2nd ed. Erlbaum, Hillsdale, N.J.Google Scholar
Congdon, J. D., Nagle, R. D., Kinney, O. M., van Loben Sels, R. C., Quinter, T., and Tinkle, D. W.. 2003. Testing hypotheses of aging in long-lived painted turtles (Chrysemys picta). Experimental Gerontology 38:765772.CrossRefGoogle Scholar
Congdon, J. D., Whitfield Gibbons, J., Brooks, R. J., Rollinson, N., and Tsaliagos, R. N.. 2013. Indeterminate growth in long-lived freshwater turtles as a component of individual fitness. Evolutionary Ecology 27:445459.CrossRefGoogle Scholar
Cothran, E. G., Aivaliotis, M. J., and Vandeberg, J. L.. 1985. The effects of diet on growth and reproduction in grey short-tailed opossums, Monodelphis domestica. Journal of Experimental Zoology 236:103114.CrossRefGoogle Scholar
Cott, H. B. 1961. Scientific results of an inquiry into the ecology and economic status of the Nile crocodile (Crocodylus niloticus) in Uganda and northern Rhodesia. Transactions of the Zoological Society of London 29:211256.CrossRefGoogle Scholar
Crawford, N. G., Parham, J. F., Sellas, A. B., Faircloth, B. C., Glenn, T. C., Papenfuss, T. J., Henderson, J. B., Hansen, M. H., and Simison, W. B.. 2015. A phylogenomic analysis of turtles. Molecular Phylogenetics and Evolution 83:250257.CrossRefGoogle ScholarPubMed
Crompton, A. W. 1963. Tooth replacement in the cynodont Thrinaxodon liorhinus Seeley. Annals of the South African Museum 46:479521.Google Scholar
Crompton, A. W. 1995. Masticatory function in nonmammalian cynodonts and early mammals. Pp. 5575 in J. J. Thomason, ed. Functional morphology in vertebrate paleontology. Cambridge University Press, Cambridge.Google Scholar
Crompton, A. W., and Jenkins, F. A.. 1973. Mammals from reptiles: a review of mammalian origins. Annual Review of Earth and Planetary Sciences 1:131155.CrossRefGoogle Scholar
Crompton, A. W., and Jenkins, F. A.. 1979. Origin of mammals. Pp. 5973 in J. Lillegraven, Z. Kielan-Jaworowska, and W. Clemens, eds. Mesozoic mammals: the first two thirds of mammalian history. University of California Press, Berkeley.Google Scholar
Crompton, A. W., and Luo, Z.-X.. 1993. Relationships of the Liassic mammals Sinoconodon, Morganucodon, and Dinnetherium. Pp. 3044 in F. S. Szalay, M. J. Novacek, and M. C. McKenna, eds. Mammal phylogeny: mesozoic differentiation, multituberculates, monotremes, early therians, and marsupials. Springer, New York.CrossRefGoogle Scholar
Crompton, A. W., and Parker, P.. 1978. Evolution of the mammalian masticatory apparatus: the fossil record shows how mammals evolved both complex chewing mechanisms and an effective middle ear, two structures that distinguish them from reptiles. American Scientist 66:192201.Google Scholar
Crompton, A. W., Wood, C. B., and Stern, D. N.. 1994. Differential wear of enamel: a mechanism for maintaining sharp cutting edges. Advances in Comparative and Environmental Physiology 18:321346.CrossRefGoogle Scholar
Curran-Everett, D. 2000. Multiple comparisons: philosophies and illustrations. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology 279:18.Google ScholarPubMed
Dawbin, W. H. 1982. The tuatara Sphenodon punctatus: aspects of life history, growth and longevity. In D. G. Newman, ed. New Zealand herpetology. New Zealand Wildlife Service, Department of Internal Affairs, Occasional Publications 2:237–250.Google Scholar
de Buffrénil, V., Ineich, I., and Böhme, W.. 2004. Comparative data on epiphyseal development in the family Varanidae. Journal of Herpetology 37:328335.Google Scholar
de Magalhaes, J. P., and Costa, J.. 2009. A database of vertebrate longevity records and their relation to other life-history traits. Journal of Evolutionary Biology 22:17701774.CrossRefGoogle ScholarPubMed
de Ricqlès, A. 1969. Recherches paléohistologiques sur les os longs des Tétrapodes. II, Quelques observations sur la structure des longs des Thériodontes. Annales de Paléontologie (Vertébrés) 55:152.Google Scholar
de Ricqlès, A. 1976. On bone histology of fossil and living reptiles, with comments on its functional and evolutionary significance. Pp. 123150 in A. A. Bellairs, and C. B. Cox, eds. Morphology and biology of reptiles (Linnean Society Symposium Series No. 3). Academic, London.Google Scholar
Dice, L. R., and Bradley, R. M.. 1942. Growth in the deer-mouse, Peromyscus maniculatus. Journal of Mammalogy 23:416427.CrossRefGoogle Scholar
Dunham, A. E., and Gibbons, J. W.. 1990. Growth of the slider turtle. Pp. 135145 in J. W. Gibbons, ed. Life history and ecology of the slider turtle. Smithsonian Institution Press, Washington, D.C.Google Scholar
Edmund, A. G. 1960. Tooth replacement phenomena in the lower vertebrates. Contributions of Royal Ontario Museum, Life Science Division 52:1190.Google Scholar
Eisen, E. J. 1976. Results of growth curve analyses in mice and rats. Journal of Animal Science 42:10081023.CrossRefGoogle ScholarPubMed
Erickson, G. M. 2005. Assessing dinosaur growth patterns: a microscopic revolution. Trends in Ecology and Evolution 20:677684.CrossRefGoogle ScholarPubMed
Erickson, G. M., Curry Rogers, K., and Yerby, S. A.. 2001. Dinosaurian growth patterns and rapid avian growth rates. Nature 412:429433.CrossRefGoogle ScholarPubMed
Evans, S. E. 1980. The skull of a new eosuchian reptile from the Lower Jurassic of South Wales. Zoological Journal of the Linnean Society 70:203264.CrossRefGoogle Scholar
Evans, S. E., and Jones, M. E. H.. 2010. The origin, early history and diversification of lepidosauromorph reptiles. In S. Bandyopadhyay, ed. New aspects of Mesozoic biodiversity. Lecture Notes in Earth Sciences 132:27–44. Springer, Berlin.Google Scholar
Evans, S. E., and Kermack, K. A.. 1994. Assemblages of small tetrapods from the Early Jurassic of Britain. Pp. 271283 in N. C. Fraser, and H.-D. Sues, eds. In the shadow of the dinosaurs. Cambridge University Press, Cambridge.Google Scholar
Ewer, R. F. 1963. Reptilian tooth replacement. News Bulletin of the Zoological Society of South Africa 4:49.Google Scholar
Fernandez, S. 1998. Age, growth and calving season of bottlenose dolphins, Tursiops truncatus, off coastal Texas. Fishery Bulletin 96:357365.Google Scholar
Frazer, N. B., and Ladner, R. C.. 1986. A growth curve for green sea turtles, Chelonia mydas, in the U.S. Virgin Islands, 1913–14. Copeia 3:798802.CrossRefGoogle Scholar
Geiger, M., Forasiepi, A. M., Koyabu, D., and Sánchez-Villagra, M. R.. 2014. Heterochrony and post-natal growth in mammals—an examination of growth plates in limbs. Journal of Evolutionary Biology 27:98115.CrossRefGoogle ScholarPubMed
Godfrey, L. R., Samonds, K. E., Wright, P.C., and King, S. J.. 2005. Schultz’s unruly rule: dental developmental sequences and schedules in small-bodied, folivorous lemurs. Folia Primatologica 76:7799.CrossRefGoogle ScholarPubMed
Gow, C. E. 1985. Apomorphies of the Mammalia. South African Journal of Science 81:558560.Google Scholar
Grine, F. E., and Vrba, E. S.. 1980. Prismatic enamel: a pre-adaptation for mammalian diphyodonty? South African Journal of Science 76:139141.Google Scholar
Haines, R. W. 1969. Epiphyses and sesamoids. Pp. 81115 in C. Gans, A. d’A. Bellairs, and T. S. Parsons, eds. Biology of the Reptilia, Vol. 1A. Morphology. Academic, London.Google Scholar
Harvey, P. H., and Pagel, M. D.. 1991. The comparative method in evolutionary biology. Oxford University Press, Oxford.Google Scholar
Helmink, S. K., Shanks, R. D., and Leighton, E. A.. 2000. Breed and sex differences in growth curves for two breeds of dog guides. Journal of Animal Science 78:2732.CrossRefGoogle ScholarPubMed
Hopson, J. A. 1971. Postcanine replacement in the gomphodont cynodont Diademodon. Pp. 121 in D. M. Kermack, and K. A. Kermack, eds. Early mammals. Academic, London.Google Scholar
Hopson, J. A. 1973. Endothermy, small size and the origin of mammalian reproduction. American Naturalist 107:446452.CrossRefGoogle Scholar
Hurum, J. H., and Chinsamy-Turan, A.. 2012. The radiation, bone histology, and biology of early mammals. Pp. 248270 in A. Chinsamy-Turan, ed. Forerunners of mammals: radiation, histology, biology. Indiana University Press, Bloomington.Google Scholar
Huttenlocker, A. K., and Botha-Brink, J.. 2014. Bone microstructure and the evolution of growth patterns in Permo-Triassic therocephalians (Amniota, Therapsida) of South Africa. PeerJ 2:e325.CrossRefGoogle Scholar
Jackson, C. M., and Lowrey, L. G.. 1912. On the relative growth of the component parts (head, trunk and extremities) and systems (skin, skeleton, musculature and viscera) of the albino rat. Anatomical Record 6:449474.CrossRefGoogle 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 8:124.CrossRefGoogle Scholar
Kemp, T. S. 2005. The origin and evolution of mammals. Oxford University Press, Oxford.Google Scholar
Kemp, T. S. 2007. The concept of correlated progression as the basis of a model for the evolutionary origin of major new taxa. Proceedings of the Royal Society of London B 274:16671673.CrossRefGoogle ScholarPubMed
Kermack, K. A., and Kermack, D. M.. 1984. Evolution of mammalian characters. Croom Helm, London.CrossRefGoogle Scholar
Kermack, K. A., Mussett, F., and Rigney, H. W.. 1973. The lower jaw of Morganucodon. Zoological Journal of the Linnean Society 53:87175.CrossRefGoogle Scholar
Kermack, K. A., Mussett, F., and Rigney, H. W.. 1981. The skull of Morganucodon. Zoological Journal of the Linnean Society 71:1158.CrossRefGoogle Scholar
Kielan-Jaworowska, Z., and Dashzeveg, D.. 1998. Early Cretaceous amphilestid (‘triconodont’) mammals from Mongolia. Acta Palaeontologica Polonica 43:413438.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.CrossRefGoogle Scholar
Köhler, M., Marín-Moratalla, N., Jordana, X., and Aanes, R.. 2012. Seasonal bone growth and physiology in endotherms shed light on dinosaur physiology. Nature 487:358361.CrossRefGoogle ScholarPubMed
Kolarov, T., Ljubisavljević, K., Polović, L., Džukić, G., and Kalezić, M. L.. 2010. The body size, age structure and growth pattern of the endemic Balkan Mosor rock lizard (Dinarolacerta mosorensis, Kolombatović, 1886). Acta Zoologica Academiae Scientiarum Hungaricae 56:5571.Google Scholar
Krogman, W. M. 1931. Growth changes in the skull and face of the gorilla. American Journal of Anatomy 47:89115.CrossRefGoogle Scholar
Kühne, W. G. 1956. The Liassic therapsid Oligokyphus. Trustees of the British Museum, London.Google Scholar
Lee, A. H., and Werning, S.. 2008. Sexual maturity in growing dinosaurs does not fit reptilian growth models. Proceedings of the National Academy of Sciences USA 105:582587.CrossRefGoogle Scholar
Lee, A. H., Huttenlocker, A. K., Padian, K., and Woodward, H. N.. 2013. Analysis of growth rates. Pp. 217251 in K. Padian, and E.-T. Lamm, eds. Bone histology of fossil tetrapods: advancing methods, analysis and interpretation. University of California Press, Berkeley.Google Scholar
Lovich, J. E., Ernst, C. H., and McBreen, J. F.. 1990. Growth, maturity, and sexual dimorphism in the wood turtle, Clemmys insculpta. Canadian Journal Zoology 68:672677.CrossRefGoogle Scholar
Luo, Z.-X. 1994. Sister-group relationships of mammals and transformations of diagnostic mammalian characters. Pp. 98128 in N. C. Fraser, and H.-D. Sues, eds. In the shadow of the dinosaurs. Cambridge University Press, Cambridge.Google Scholar
Luo, Z.-X., Crompton, A. W., and Sun, A.-L.. 2001. A new mammal from the Early Jurassic and evolution of mammalian characteristics. Science 292:15351540.CrossRefGoogle ScholarPubMed
Luo, Z.-X., Kielan-Jaworowska, Z., and Cifelli, R. L.. 2002. In quest for a phylogeny of Mesozoic mammals. Acta Palaeontologica Polonica 47:178.Google Scholar
Luo, Z.-X., Kielan-Jaworowska, Z., and Cifelli, R. L.. 2004. Evolution of dental replacement in mammals. Bulletin of the Carnegie Museum of Natural History 36:159175.CrossRefGoogle Scholar
Maisano, J. A. 2002. Terminal fusions of skeletal elements as indicators of maturity in squamates. Journal of Vertebrate Paleontology 22:268275.CrossRefGoogle Scholar
Martin, T., and Nowotny, M.. 2000. The docodont Haldanodon from the Guimarota mine. Pp. 9196 in T. Martin, and B. Krebs, eds. Guimarota—a Jurassic ecosystem. Verlag Dr. Friedrich Pfeil, Munich.Google Scholar
Martinelli, A. G., and Bonaparte, J. F.. 2011. Postcanine replacement in Brasilodon and Brasilitherium (Cynodontia, Probainognathia) and its bearing in cynodont evolution. Pp. 179186 in J. Calvo, J. Porfiri, B. Gonzales Riga, and D. Dos Santos, eds. Paleontología y Dinosaurios desde América Latina Editora de la Universidad de Cuyo. Mendoza, Argentina.Google Scholar
Moss, M. L., and Baer, M. J.. 1956. Differential growth of the rat skull. Growth 20:107120.Google Scholar
Mills, J. R. E. 1971. The dentition of Morganucodon. Pp. 2963 in D. M. Kermack, and K. A. Kermack, eds. Early mammals. Academic, London.Google Scholar
Münkemüller, T., Lavergne, S., Bzeznik, B., Dray, S., Jombart, T., Schiffers, K., and Thuiller, W.. 2012. How to measure and test phylogenetic signal. Methods in Ecology and Evolution 3:743756.CrossRefGoogle Scholar
Nesterenko, V., and Ohdachi, S.. 2001. Postnatal growth and development in Sorex unguiculatus. Mammal Study 26:145148.CrossRefGoogle Scholar
Nowotny, M., Martin, T., and Fischer, M. S.. 2001. Dental anatomy and tooth replacement of Haldanodon exspectatus (Docodonta, Mammalia) from the Upper Jurassic of Portugal. Journal of Morphology 248:268.Google Scholar
Osborn, J. W. 1971. The ontogeny of tooth succession in Lacerta vivipara, Jacquine (1787). Proceedings of the Royal Society of London B 179:261289.CrossRefGoogle Scholar
Osborn, J. W. 1974. On the control of tooth replacement in reptiles and its relationship to growth. Journal of Theoretical Biology 46:509527.CrossRefGoogle Scholar
Osborn, J. W., and Crompton, A. W.. 1973. The evolution of mammalian from reptilian dentitions. Breviora 399:118.Google Scholar
Padian, K., de Ricqlès, A. J., and Horner, J. R.. 2001. Dinosaurian growth rates and bird origins. Nature 412:405408.CrossRefGoogle Scholar
Parrington, F. R. 1971. On the Upper Triassic mammals. Philosophical Transactions of the Royal Society of London B 261:231272.CrossRefGoogle Scholar
Parrington, F. R. 1973. The dentitions of the earliest mammals. Zoological Journal of the Linnean Society 52:8595.CrossRefGoogle Scholar
Parrington, F. R. 1978. A further account of the Triassic mammals. Philosophical Transactions of the Royal Society of London B 282:177204.CrossRefGoogle Scholar
Pond, C. M. 1977. The significance of lactation in the evolution of mammals. Evolution 31:177199.CrossRefGoogle Scholar
Porter, K. R. 1972. Herpetology. Saunders, Philadelphia.Google Scholar
Ray, S., Bandyopadhyay, S., and Bhawal, D.. 2009. Growth patterns as deduced from bone microstructure of some selected neotherapsids with special emphasis on dicynodonts: phylogenetic implications. Palaeoworld 18:5366.CrossRefGoogle Scholar
Ray, S., Botha, J., and Chinsamy, A.. 2004. Bone histology and growth patterns of some nonmammalian therapsids. Journal of Vertebrate Paleontology 24:634648.CrossRefGoogle Scholar
R Core Team. 2012. R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Scholar
Robinson, P. L. 1957. The Mesozoic fissures of the Bristol Channel area and their vertebrate faunas. Zoological Journal of the Linnean Society 43:260282.CrossRefGoogle Scholar
Rootes, W. L., Chabreck, R. H., Wright, V. L., Brown, B. W., and Hess, T. J.. 1991. Growth rates of American alligators in estuarine and palustrine wetlands in Louisiana. Estuaries 14:489494.CrossRefGoogle Scholar
Rowe, T. B. 1998. Definition, diagnosis, and origin of Mammalia. Journal of Vertebrate Paleontology 8:241264.CrossRefGoogle Scholar
Säilä, L. K. 2005. A new species of the sphenodontian reptile Clevosaurus, from the Lower Jurassic of South Wales. Palaeontology 48:817831.CrossRefGoogle Scholar
Sander, P. M., and Klein, N.. 2005. Developmental plasticity in the life history of a prosauropod dinosaur. Science 310:18001802.CrossRefGoogle Scholar
Scheyer, T. M., Klein, N., and Sander, M.. 2010. Developmental palaeontology of Reptilia as revealed by histological studies. Seminars in Cell and Developmental Biology 21:462470.CrossRefGoogle ScholarPubMed
Schrader, A. M., Ferreira, S. M., McElveen, M. E., Lee, P.C., Moss, C. J., and van Aarde, R. J.. 2006. Growth and age determination of African savanna elephants. Journal of Zoology 270:4048.Google Scholar
Sebens, K. P. 1987. The ecology of indeterminate growth in animals. Annual Review of Ecology and Systematics 18:71407.CrossRefGoogle Scholar
Seminoff, J. A., Resendiz, A., Nichols, W. J., and Jones, T. T.. 2002. Growth rates of wild green turtles (Chelonia mydas) at a temperate foraging area in the Gulf of California, México. Copeia 3:610617.CrossRefGoogle Scholar
Shine, R., and Charnov, E. L.. 1992. Patterns of survival, growth, and maturation in snakes and lizards. American Naturalist 39:12571269.CrossRefGoogle Scholar
Shine, R., and Iverson, J. B.. 1995. Patterns of survival, growth and maturation in turtles. Oikos 72:343348.CrossRefGoogle Scholar
Sokal, R. R., and Rohlf, F. J.. 2012. Biometry, 4th ed. Freeman, New York.Google Scholar
Tabachnick, B. G., and Fidell, L. S.. 2007. Using Multivariate Statistics, 5th ed. Pearson Education, Boston.Google Scholar
Tucker, A. D., Limpus, C. J., McDonald, K. R., and McCallum, H. I.. 2006. Growth dynamics of freshwater crocodiles (Crocodylus johnstoni) in the Lynd River, Queensland. Australian Journal of Zoology 54:409415.CrossRefGoogle Scholar
Tyndale-Biscoe, C. H. 2001. Australasian marsupials—to cherish and to hold. Reproduction, Fertility and Development 13:477485.CrossRefGoogle Scholar
van Devender, R. W. 1978. Growth ecology of a tropical lizard, Basiliscus basiliscus. Ecology 59:10311038.CrossRefGoogle Scholar
Westergaard, B., and Ferguson, M. W. J.. 1986. Development of the dentition in Alligator mississippiensis. Early embryonic development in the lower jaw. Journal of Zoology 210:575597.CrossRefGoogle Scholar
Westergaard, B., and Ferguson, M. W. J.. 1987. Development of the dentition in Alligator mississippiensis. Later development in the lower jaws of embryos, hatchlings and young juveniles. Journal of Zoology 212:199222.CrossRefGoogle Scholar
Wilkinson, P. M., and Rhodes, W. E.. 1997. Growth rates of American alligators in coastal South Carolina. Journal of Wildlife Management 61:397402.CrossRefGoogle Scholar
Woodward, H. N., Horner, J. R., and Farlow, J. O.. 2011. Osteohistological evidence for determinate growth in the American alligator. Journal of Herpetology 45:339342.CrossRefGoogle Scholar
Zhang, F.-K., Crompton, A. W., Luo, Z.-X., and Schaff, C. R.. 1998. Pattern of dental replacement of Sinoconodon and its implications for evolution of mammals. Vertebrata PalAsiatica 36:197217.Google Scholar
Zug, G. R., Wynn, A. H., and Ruckdeschel, C.. 1986. Age determination of loggerhead sea turtles, Caretta caretta, by incremental growth marks in the skeleton. Smithsonian Contributions to Zoology 427:134.CrossRefGoogle Scholar
Zúñiga-Vega, J. J., Rojas-González, R. I., Lemos-Espinal, J. A., and Pérez-Trejo, M. E.. 2005. Growth ecology of the lizard Xenosaurus grandis in Veracruz, México. Journal of Herpetology 39:433443.CrossRefGoogle Scholar