Dinosaurs Without Bones

by Anthony J. Martin

  p. 64 “Persuasive circumstantial evidence leads us to conclude that they represent a stampede—that is, a wild, unreasoning and panic-stricken rush to escape the threat of danger. What could have caused such presumed panic?” Thulborn and Wade (1979).

  p. 65 “The second, published in 1984, was a much longer and more detailed report modestly titled ‘Dinosaur Trackways in the Winton Formation (Mid-Cretaceous) of Queensland.’” Thulborn, R.A., and Wade, M. 1984. Dinosaur trackways in the Winton Formation (mid-Cretaceous) of Queensland. Memoirs Queensland Museum, 21: 413-517.

  p. 67 “The fresh hypothesis states that the ‘dinosaur stampede’ was not triggered by the arrival of a predator, and no stalking of other dinosaurs by a voracious predator happened either.” Romilio, A., and Salisbury, S.W. 2011. A reassessment of large theropod dinosaur tracks from the mid-Cretaceous (late Albian–Cenomanian) Winton Formation of Lark Quarry, central-western Queensland, Australia: a case for mistaken identity. Cretaceous Research, 32: 135-142.

  p. 69 “After all, hypotheses are only accepted conditionally, and then are subject to further testing so we can find out whether or not they still hold up to scrutiny.” Cleland, C.E. 2001. Historical science, experimental science, and the scientific method. Geology, 29: 987-990.

  p. 70 “Why identifying the maker of these big tracks is so difficult is mostly attributable to the tracks only having three toes, a trait also known as tridactyl.” Farlow et al. (2012).

  p. 70 “On average, theropod tracks are longer than they are wide, whereas ornithopod tracks are wider than they are long.” (1) Lockley (2009); (2) Farlow et al. (2012).

  p. 71 “In an article published in 1988, they used a sample of 66 Early Cretaceous tridactyl dinosaur tracks from Spain, all of which had been identified confidently as either ornithopod or theropod tracks on the basis of their qualities.” Moratalla, J.J., Sanz., S.L., and Jimenez, S. 1988. Multivariate analysis on Lower Cretaceous dinosaur footprints: discrimination between ornithopods and theropods. Geobios, 21: 395-408.

  p. 73 “Skeletal remains of this ornithopod were discovered in 1963 near the small town of Muttaburra in central Queensland, northeast of Lark Quarry… .” Bartholomai, A., and Molnar, R.E. 1981. Muttaburrasaurus: a new Iguanodontid (Ornithischia:Ornithopoda) dinosaur from the Lower Cretaceous of Queensland. Memoirs of the Queensland Museum, 20: 319-349.

  p. 73 “In contrast, bones of only one large predatory theropod … Australovenator wintonensis, lovingly nicknamed ‘Banjo’… .” Hocknull, S.A., White, M.A., Tischler, T. R., Cook, A.G., Calleja, N.D., Sloan, T., and Elliott, D. A. 2009. New mid-Cretaceous (Latest Albian) dinosaurs from Winton, Queensland, Australia. PLoS One, 4: e6190.

  p. 74 “Interestingly, objections to this identification, voiced formally by Romilio and Salisbury, were not new, as a few dinosaur paleontologists questioned it soon after Thulborn and Wade’s second article came out in 1984.” (1) Paul, G. 1988. Predatory Dinosaurs of the World. Simon and Shuster, New York: 464 p. (2) Lockley and Hunt (1994).

  p. 74 “I say the last facetiously, but a small troupe of creative folks actually did write and perform a short musical number retelling the original story of the dinosaur stampede… .” The performance was recorded, placed on YouTube on September 29, 2012, and is titled Dinosaur Stampede MASA2012: http://www.youtube.com/ watch?v=midGaNNHhbM

  p. 77 “In this manuscript, which was posted online in the same journal (Cretaceous Research) that published the re-study… .” The article was initially available online November 22, 2011, then withdrawn sometime before May 2012. Apparently, the author was never notified by the journal of the withdrawal, and learned about its disappearance from others. The link to the former article and the “Withdrawn” notice are here: http://www.sciencedirect.com/science/article/pii/S0195667111001844

  p. 78 “Hence, it did what very few academic journals do, which was pull the article offline.” As part of an online scientific community, I recall the surprise and discussion that took place among paleontologists after this happened, with much speculation about why it was justified. Some of this is summarized by Brian Switek, along with his coverage of the new interpretation of the “stampede” track-site as a “swimsite,” here: http://phenomena.nationalgeographic.com/2013/01/11/swim-tracks-undermine-dinosaur-stampede/

  p. 79 “Thulborn submitted a revised version of his article to the Australian Thulborn, R.A. (2013): Lark Quarry revisited: a critique of methods used to identify a large dinosaurian track-maker in the Winton Formation (Albian–Cenomanian), western Queensland, Australia. Alcheringa: An Australasian Journal of Palaeontology, doi:10.1080/03115518.20 13.748482

  p. 79 “Then, also early in 2013, the aquamusical version was unveiled.” Romilio, A., Tucker, R., and Salisbury, S.W. 2013. Reevaluation of the Lake Quarry dinosaur tracksite (late Albian-Cenomanian Winton Formation, central-western Queensland, Australia): no longer a stampede? Journal of Vertebrate Paleontology, 33: 102-120.

  p. 80 “Just how did I get trapped in the building housing these fabled and controversial dinosaur tracks?” Much of this story I told before in an invited article for Australian Age of Dinosaurs magazine (2011 issue), written as a humorous end piece to the magazine (called the “Tail Bone”) and titled Sleeping with the Dinosaur Tracks.

  CHAPTER 4: DINOSAUR NESTS AND BRINGING UP BABIES

  p. 86 “How did male dinosaurs get past the thick tails of some females to reach their goals? More intriguing, how did male dinosaurs get past the spiky or clubbed tails of some females?” Brian Switek, in his book My Beloved Brontosaurus (2013, Farrar, Straus, and Giroux, 256 p.), explores the intriguing topic of dinosaur sex with great humor and deeply penetrating prose in a chapter titled “The Big Bang Theory.” In this chapter, he discusses the pros and cons of dinosaur positions, so with those in mind, it is even more fun to imagine the traces these would have made.

  p. 87 “This discovery was of a small ceratopsian dinosaur, Protoceratops, on top of a dromaeosaur, Velociraptor, with both locked in an embrace but a pointedly deadly one.” Although this deservedly famous pair of fossils has been much discussed since its discovery in 1971, the first peer-reviewed publication reporting it was: Barsbold, R. 1974. Saurornithoididae, a new family of theropod dinosaurs from Central Asia and North America. Paleontologica Polonica, 30: 5-22.

  p. 87 “… but more emblematic of Tennyson’s ‘nature, red in tooth and claw.’” This famous phrase, with its allusions to Darwinian struggles (albeit ten years before publication of Darwin’s On the Origin of Species) comes from section (Canto) 56 of Alfred, Lord Tennyson’s epic poem, In Memoriam A.H.H., finished in 1849. This poem is explored in depth by a Stephen Jay Gould essay, “The Tooth and Claw Centennial,” in: Gould, S.J. 1995. Dinosaur in a Haystack. Harmony Books, New York: 63-75.

  p. 87 “Paleontologists who studied these fossils agree that both dinosaurs must have been buried instantaneously… .” So much has been written about these dinosaurs and how they were buried, I won’t even try to pick any one. But probably the best general explanation for how collapsing dunes (and wet sand) could have been responsible for the exquisite preservation of the Late Cretaceous Mongolian dinosaurs is: Dingus, L., and Loope, D. 2000. Death in the dunes. Natural History, 109: 50-57.

  p. 90 “Nonetheless, eggs and eggshells are actually body fossils.” Martin, A.J. 2006. Introduction to the Study of Dinosaurs (2nd Edition). Wiley-Blackwell, Oxford, U.K.: 560 p.

  p. 91 “Vertebrates that lay eggs today, such as reptiles, birds, and monotremes (egg-laying mammals, such as the platypus and echidnas), are all classified as amniotes.” Benton, M.J. 2005. Vertebrate Palaeontology (3rd Edition). Wiley-Blackwell, Oxford, U.K.: 455 p.

  p. 91 “We currently have no reasonable evidence that dinosaurs gave birth to live young, but this trait (viviparity) showed up in ichthyosaurs… .” Many articles have been published on individual ichthyosaurs and their giving live birth. But for an exploration of how it evolved in Mesozoic marine reptiles, as well as an overview of the evidence for bi
ological development in fossils, read: Sánchez, M.R. 2012. Embryos in Deep Time: The Rock Record of Biological Development. University of California Press, Berkeley, California: 265 p.

  p. 91 “Although that strategy has worked very well for sea turtles for the past 100 million years… .” A fossil sea-turtle nest—from the Cretaceous Period, no less—was just recently described in detail, with its traits compared to those of modern sea turtles: Bishop, G.A., Pirkle, F.L., Meyer, B.K., and Pirkle, W.A. 2011. The foundation for sea turtle geoarchaeology and zooarchaeology: morphology of recent and ancient sea turtle nests, St. Catherines Island, Georgia, and Cretaceous Fox Hills Sandstone, Elbert County, Colorado. In Bishop, G.A, Rollin, H.B., and Thomas, D.H. (editors), Geoarchaeology of St. Catherines Island, Georgia. Anthropological Papers of the American Museum of Natural History, No. 94: 247-269.

  p. 91 “Viviparity also occurs in some modern species of lizards and snakes, including sea snakes… .” Andrews, R.M., and Mathies, T. 2000. Natural history of reptilian development: constraints on the evolution of viviparity. BioScience, 50: 227-238.

  p. 92 “The oldest known dinosaur eggs come from Early Jurassic rocks… .” Reisz, R.R., Evans, D.C., Roberts, E.M., Dieter-Sues, H., and Yates, A.M. 2012. Oldest known dinosaurian nesting site and reproductive biology of the Early Jurassic sauropodomorph Massospondylus. Proceedings of the National Academy of Science, 109: 2428-2433.

  p. 92 “These categories, based on shell microstructure, arrangements of the pores, and overall forms, were given linguistically daunting names such as Spheroolithidae, Ovaloolithidae….” Zelenitsky, D. K., Horner, J.R., and Therrien, F. 2012. Dinosaur eggs. In Brett-Surman, M.K., Holtz, T.R., Jr., and Farlow, J.O. (editors), The Complete Dinosaur (2nd Edition). Indiana University Press, Bloomington, Indiana: 613-620.

  p. 93 “Paleontologists who studied Troodon egg clutches were surprised to notice that not only were eggs paired but also aligned vertically.” Varricchio et al. (1997).

  p. 93 “Thus far, we only know of one instance in which an egg assemblage contained embryonic bones of more than one species of dinosaur… .” This find was first described in 1994, then updated in 2009. (1) Norell, M.A., Clark, J.M., Dashzeveg, D., Barsbold, R., Chiappe, L.M., Davidson, A.R., McKenna, M.C., Perle, A., and Novacek, M.J. 1994. A theropod dinosaur embryo and the affinities of the Flaming Cliffs dinosaur eggs. Science, 266: 779-782. (2) Bever, G.S., and Norell, M.A. 2009. The perinate skull of Byronosaurus (Troodontidae) with observations on the cranial ontogeny of paravian theropods. American Museum Novitates, 3657: 51 p.

  p. 94 “Sea turtles, for example, have a temporary extension of their beaks when born, which is applied like a can opener from the inside of the egg to open it.” Ruckdeschel, C., and Shoop, C.R. 2006. Sea Turtles of the Atlantic and Gulf Coasts of the United States. University of Georgia Press, Athens, Georgia: 152 p.

  p. 94 “Similar parts have been described from Late Cretaceous sauropod embryos in Argentina… .” Garcia, R.A. 2007. An “egg-tooth”-like structure in titanosaurian sauropod embryos. Journal of Vertebrate Paleontology, 27: 247-252.

  p. 94 “Have hatchling trace fossils been identified in dinosaur eggs?” Mueller-Töwe, I. J., Sander, P.M., Schüller, H., and Thies, D. 2002. Hatching and infilling of dinosaur eggs as revealed by computed tomography. Palaeontographica Abteilung A, 267: 119-168.

  p. 95 “Yet these trace fossils have not been discovered yet either, despite many decades of our demonizing mammals for eating too many dinosaur eggs… .” No one is quite sure when the “Mammals ate dinosaur eggs, so dinosaurs went extinct” idea originated, but it is a persistent myth. And myth it is, because dinosaurs and mammals lived together in the Mesozoic for about 150 million years, yet we still have no evidence—trace fossil or otherwise—for mammals eating dinosaur eggs, let alone eating enough of them to hasten dinosaur extinction.

  p. 96 “Unidentified therizinosaurs from the Late Cretaceous of Mongolia, which may have even formed nesting colonies.” This fantastic discovery of a probable therizinosaur nesting colony was announced in a talk at the Society of Vertebrate Paleontology meeting in October 2013: Kobayashi, Y., Lee, Y.-N., Barsbold, R., Zelenitsky, D., and Tanaka, K. 2013. First record of a dinosaur nesting colony from Mongolia reveals nesting behavior of therizinosauroids. Journal of Vertebrate Paleontology, Program and Abstracts, 2013: 155.

  p. 96 “The ceratopsians Psittacosaurus from the Early Cretaceous in China, and Protoceratops from the Late Cretaceous in Mongolia… .” (1) Meng, Q., Liu, J., Varricchio, D.J., Huang, T., and Gao, C. 2004. Parental care in an ornithischian dinosaur. Nature, 431: 145-146. (2) Fastovsky, D., Weishampel, D., Watabe, M., Barsbold, R., Tsogtbaatar, K., and Narmandakh, P. 2011. A nest of Protoceratops andrewsi (Dinosauria, Ornithischia). Journal of Paleontology, 85 (6): 1035-1041. p. 96 “… a nearly complete specimen of Citipati osmolskae—missing only its head—was found in a sitting position above a clutch of long oval eggs.” (1) Norell, M.A., Clark, J.M., Chiappe, L.M., and Dashzeveg, D. 1995. A nesting dinosaur. Nature, 378: 774-776. (2) 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 avian-like brooding position over an oviraptorid nest. American Museum Novitates, 3265: 1-36.

  p. 97 “Indeed, the discovery of a dinosaur egg—containing embryonic bones, no less—in Late Cretaceous shallow-marine deposits in Alabama… .” Lamb, J.P., Jr. 2001. Dinosaur egg with embryo from the Cretaceous (Campanian) Mooreville Chalk Formation, Alabama. Journal of Vertebrate Paleontology, 21 (Supplement to 3): 70A.

  p. 97 “If talking just about reptile nests, these can be summarized into two broad categories: ground nests and hole nests, with ground nests made on the ground surface and hole nests below the surface.” Martin (2006). p. 98 “Bird nests range from simple scrapes in the ground, to better defined excavations… .” Elbroch, M., and Marks, E. 2001. Bird Tracks and Sign of North America. Stackpole Books, Mechanicsburg, Pennsylvania: 456 p.

  p. 98 “For instance, one good candidate for underground nesting would have been the small Cretaceous ornithopod Oryctodromeus cubicularis… .” Varricchio et al. (2007). p. 98 “For arboreal nests, a few small feathered tree-climbing, gliding, and flying non-avian dinosaurs are known from Early Cretaceous rocks of China.” (1) Czerkas, S.A., and Yuan, C. 2002. An arboreal maniraptoran from northeast China. In Czerkas, S.J. (editor), Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum Journal 1. The Dinosaur Museum, Blanding, Utah: 63-95. (2) Zhang, F., Zhou, Z., Xu, X., Wang, X., and Sullivan, C. 2008. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers. Nature, 455: 1105-1108.

  p. 99 “Fortunately, paleontologists who have interpreted the few indisputable dinosaur nests in the geologic record made a nice little checklist for the rest of us to follow… .” Chiappe et al. (2004).

  p. 100 “At the time of this discovery, more than a hundred years had elapsed between paleontologists first linking fossil eggs to dinosaurs, which was in 1869.” Matheron, M. 1869. Notice sur les Reptiles fossils des depots fluvio-lacustres Crétacés du basin a lignote de Fuveau. Memoires l’Academie Impériale des Sciences, Belles-Lettres et Arts de Marseille: 345-379.

  p. 100 “… John (‘Jack’) Horner and his friend Robert (‘Bob’) Makela … found depressions filled with eggs and partly grown juveniles of the large ornithopod dinosaur Maiasaura peeblesorum.” (1) Horner, J.R., and Makela, R. 1979. Nest of juveniles provides evidence of family structure among dinosaurs. Nature, 282: 296-298. (2) Horner, J.R. 1982. Evidence of colonial nesting and ‘site fidelity’ among ornithischian dinosaurs. Nature, 297: 675-676. (3) Horner, J.R. 1984. The nesting behavior of dinosaurs. Scientific American, 250: 130-137.

  p. 101 “Recognized by David (‘Dave’) Varricchio, who was a Ph.D. student of Horner’s in the early 1990s, these structures were the first dinosaur nests defined solely as trace fossils.” (1) Varricchio et al. (1997, 1999).

  p. 102 “Eggs in the clutch were oriented almost vertically
, narrow ends down but also pointing toward the center.” Varricchio et al. (1997).

  p. 104 “The width of the nest, rim included, was about half the total body length of an adult Troodon… .” Varricchio et al. (1999).

  p. 104 “Just to compare, though, crocodilians and sea turtles normally take just a few hours to dig a hole nest.” (1) Kusklan, J.A., and Mazzotti, F.J. 1989. Population biology of the American crocodile. Journal of Herpetology, 23: 7-21. (2) Ruckdeschel and Shoop (2006).

  p. 105 “Some of these mounds, such as nests of the Australian brush turkey (Alectura lathami), can be 2 m (6.6 ft) tall and 20 m (67 ft) wide.” (1) Jones, D.N. 1988. Construction and maintenance of the incubation mounds of the Australian brush-turkey Alectura lathami. Emu, 88: 210-218. (2) Seymour, R.S., and Bradford, D.F. 1992. Temperature regulation in the incubation mounds of the Australian brush-turkey. The Condor, 94: 134-150.

  p. 105 “These anatomical traits of Troodon mothers are interpreted on the basis of how eggs are paired.” Varricchio et al. (1997, 1999).

  p. 106 “Even better evidence of brooding behavior is the adult itself… .” Varricchio et al. (1997, 1999). D.J., Moore, J.R., Erickson, G.M., Norell, M.A., Jackson, F.D., and Borkowski, J.J. 2008. Avian parental care had dinosaur origin. Science, 322: 1826-1828. (2) Schweitzer, M.H., Wittmeyer, J.L., and Horner, J.R. 2005. Gender-specific reproductive tissue in ratites and Tyrannosaurus rex. Science, 308: 1456-1460.

  p. 106 “Not coincidentally, this same sort of paternal protection is a modern behavior likewise seen in nesting emus, ostriches, and rheas.” Varricchio, D.J. 2011. A distinct dinosaur life history? Historical Biology, 23: 91-107.

  p. 107 “Much study on the sedimentary rocks there, including their geochemistry, revealed that this part of Montana was probably warm and semi-arid 75 to 80 million years ago.” Rogers, R.R. 1990. Taphonomy of three dinosaur bone beds in the Upper Cretaceous Two Medicine Formation of northwestern Montana: evidence for drought-related mortality. Palaios, 5: 394-413.