Dinosaurs Without Bones (56 page)

p. 30
   “Originally devised in 1976 by a paleontologically enthused physicist, R. M. Alexander… .” Alexander, R.M. 1976. Estimates of the speed of dinosaurs. Nature, 261: 129-130.

p. 31
   “Olympic racewalkers regularly exceed 15 kph, which they can keep up for 20 km (12.4 mi).” U.S. and world records for racewalking are at the following USA Track and Field (USATF) site: http://www.usatf.org/Sports/Race-Walking/Records.aspx

p. 31
   “Not surprisingly, then, other paleontologists have come up with their own formulas for estimating dinosaur speeds.” The most-often cited alternative to Alexander’s formula is here: Thulborn, R.A. 1982. Speeds and gaits of dinosaurs. Palaeogeography, Palaeoclimatology, Palaeoecology, 38: 227-256.

p. 31
   “A few have even tried to say that some dinosaurs were not capable of running at all… .” Mallison, H. 2011. Fast-moving dinosaurs: why our basic tenet is wrong. Journal of Vertebrate Paleontology [Supplement], Program and Abstracts for Society of Vertebrate Paleontology meeting, Las Vegas, Nevada: 150.

p. 32
   “In other words, tracks and these structures caused by the applied and released pressure—which some trackers call pressure-release structures, pressure releases, or indirect features… .” (1) Brown, T., Jr. 1999. The Science and Art of Tracking. Berkley Books, New York: 240 p. (2) Gatesy,
S. M. 2003. Direct and indirect track features: what sediment did a dinosaur touch? Ichnos, 10: 91-98. (3)

p. 33
   “All of these factors culminate in what paleontologists consider as ‘track tectonics’… .” Graversen, O., Milàn, J., and Loope, D.B. 2007. Dinosaur tectonics: a structural analysis of theropod undertracks with a reconstruction of theropod walking dynamics. Journal of Geology, 115: 641-654.

p. 33
   “Consequently, a common way for dinosaur tracks to have made it into the fossil record was as undertracks.” Milàn, J., and Bromley, R.G. 2006. True tracks, undertracks and eroded tracks, experimental work with tetrapod tracks in laboratory and field. Palaeogeography, Palaeoclimatology, Palaeoecology, 231: 253-264.

p. 35
   “One of these, preserved in Late Cretaceous rocks of Bolivia, was made by an ankylosaur—a big, armored dinosaur—which must have looked like a living tank as it ambled along.” Meyer, C.A., Hippler, D., and Lockley, M.G. 2001. The Late Cretaceous vertebrate ichnofacies of Bolivia: facts and implications. Asociación Palaeontológica Argentina, Publicación Especial 7: 133-138.

p. 35
   “The first discovered running-dinosaur trackways were from a site in Texas, where at least three theropods moved at high speed.” Farlow, J.O. 1981. Estimates of dinosaur speeds from a new trackway site in Texas. Nature, 294: 747-748.

p. 35
   “To put it into a bipedal-human perspective, the top speed recorded by Usain Bolt over 200 m (656 ft) during the 2012 Olympics was also 27 mph… .” Hernández-Gómez, J.J., Marquina, V., and Gómez, R.W. 2013. On the performance of Usain Bolt in the 100 m sprint. European Journal of Physics, 34: 1227.

p. 35
   “Theropods and humans alike, though, would be humbled by the top speed recorded by a cheetah (Acinonyx jubatus)… .” Sharp, N.C.C. 1997. Timed running speed of a cheetah (Acinonyx jubatus). Journal of Zoology, 241: 493-494.

p. 35
   “Nonetheless, a dinosaur tracksite in Queensland, Australia outdoes the Texas tracksite for sheer numbers of running dinosaurs.” This tracksite was first interpreted as a “dinosaur racetrack” by: Thulborn, R.A., and Wade, M. 1979. Dinosaur stampede in the Cretaceous of Queensland. Lethaia, 12: 275-279. However, it was also recently reinterpreted as a “dinosaur natatorium” (swimsite) by: 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. 36
   “For example, the fastest bipedal land animals today are ostriches (Struthio camelus), which have maximum speeds of 45 mph (72 kph).” Mechanics of running of the ostrich (Struthio camelus). Journal of Zoology, 187: 169-178.

p. 36
   “One paleontologist, Jim Farlow, and two other colleagues figured out that given the average mass of an adult T. rex… .” Farlow, J.O., Smith, M.B., and Robinson, J.M. 1995. Body mass, bone “strength indication,” and cursorial potential of Tyrannosaurus rex. Journal of Vertebrate Paleontology, 15: 713-725.

p. 37
   “What they found was that a 45-mph-running T. rex would have required about 85% of its entire body mass concentrated in its legs… .” Hutchinson, J.R., and Garcia, M. 2002. Tyrannosaurus was not a fast runner. Nature, 415: 1018-1021.

p. 37
   “Both of these skeletons belong to the same species of dinosaur, Mei long (‘soundly sleeping dragon’).” (1) Xu, X., and Norell, M.A. 2004. A new troodontid dinosaur from China with avianlike sleeping posture. Nature, 431: 838-841. (2) Gao, C., Morschhauser, E.M., Varricchio, D.J., Liu, J., and Zhao, B. 2012. A second soundly sleeping dragon: new anatomical details of the Chinese troodontid Mei long with implications for phylogeny and taphonomy. PLoS One, 7: e45203, doi:10.1371/journal.pone.0045203.

p. 38
   “A few other dinosaur skeletons, such as those of the theropod Citipati, have been found preserved in sitting positions… .” (1) Norell, M.A., Clark, J.M., Chiappe, L.M., and Dashzeveg, D. 1995. A nesting dinosaur. Nature, 378: 774-776. (2) Varricchio et al. (1997).

p. 39
   “Incidentally, dinosaur tail impressions are quite rare, with fewer than forty reported from the entire geologic record… .” Kim, J.Y., and Lockley, M.G. 2013. Review of dinosaur tail traces. Ichnos, 20: 129-141.

p. 39
   “Reported in 2009 in southwestern Utah, this Early Jurassic trace fossil not only shows where a theropod approached a sitting spot and sat down… .” Milner, A.R.C., Harris, J.D., Lockley, M.G., Kirkland, J.I., and Matthews, N.A. 2009. Bird-like anatomy, posture, and behavior revealed by an Early Jurassic theropod dinosaur resting trace. PLoS One, 4: e4591. doi:4510.1371/journal.pone.0004591.

p. 40
   “We were also testing an audacious claim that some of the wrinkle marks near the edge of the leg impressions were actually from feathers.” Martin, A.J., and Rainforth, E.M. 2004. A theropod resting trace that is also a locomotion trace: case study of Hitchcock’s specimen AC 1/7. Geological Society of America Abstracts with Programs 36(2): 96.

p. 41
   “In short, this specimen records a full sequence of movement by the theropod and how it altered the ground beneath it… .” Martin and Rainforth (2004).

p. 42
    “Only later did paleontologists realize this ‘webbing’ was actually a result of skin drying around its bones after the dinosaur had died.” Manning, P. 2008. Grave Secrets of Dinosaurs: Soft Tissues and Hard Science. National Geographic Society, Washington, D.C.: 316 p.

p. 42
   “A major flaw in this seemingly marvelous adaptation was that the hollow tube in the center of the crest, once studied in more detail later… .” Weishampel, D.B. 1981. The nasal cavity of lambeosaurine hadrosaurids (Reptilia:Ornithischia): comparative anatomy and homologies. Journal of Paleontology, 55: 1046-1057.

p. 42
   “Once he investigated, he … made an astonishing discovery: the first known sauropod dinosaur tracks from the geologic record.” Bird, R.T. 1985. Bones for Barnum Brown: Adventures of a Dinosaur Hunter. Texas Christian University Press, Ft. Worth, Texas: 225 p.

p. 43
   “Later, a closer look at these tracks showed that the missing tracks in the sequence of steps could be attributed to differences in track preservation.” Lockley, M.G., and Rice, A. 1990. Did Brontosaurus ever swim out to sea? Ichnos, 1: 81-90.

p. 43
   “These tracks are also in rocks from near the start of sauropods in the fossil record (Late Triassic) to their very end (Late Cretaceous).” Lockley et al. (2001).

p. 43
   “Yet Indian elephants (Elephas maximus) can swim as far as 25 miles (40 km), a feat far better than most humans are capable of.” Johnson, D.E. 1980. Problems in the land vertebrate zoogeography of certain islands and the swimming power of elephants. Journal of Biogeography, 7: 383-398. However, on September 2, 2013, Diana Nyad successfully completed swimming 178 km (110 mi) from Cuba to Florida, a distance that would be the envy of all water-crossing elephants.

p. 44
   “In fact, elephant swimming abilities show one of the probable ways mammoths dispersed to islands during the Pleistocene Epoch, where some isolated populations lasted until only about 4,000 years ago.” (1) Vartanyan, S.L., Garutt, V.E., and Sher, A.V. 1993. Holocene dwarf mammoths from Wrangel Island in the Siberian Arctic. Nature, 362: 337-340. (2) Johnson (1980).

p. 44
   “First, as early as 1980, a paleontologist interpreted swim tracks from Early Jurassic rocks of Connecticut as made by theropods… .” Coombs, W.P., Jr. 1980. Swimming ability of carnivorous dinosaurs. Science, 207: 1198-1200.

p. 44
   “… in 2001, paleontologists working in separate studies and places (Wyoming and the U.K.) interpreted Middle Jurassic tracks as possible dinosaur swim tracks.” (1) Kvale, E.P., Johnson, G.D., Mickelson, D.L., Keller, K., Furer, L.C., and Archer, A.W. 2001. Middle Jurassic (Bajocian and Bathonian) dinosaur megatracksites, Bighorn Basin, Wyoming, U.S.A. Palaios, 16: 233-254. (2) Whyte, M.A., and Romano, M. 2001. A dinosaur ichonocoenoses from the Middle Jurassic of Yorkshire, UK. Ichnos, 8: 223-234.

p. 44
   “Soon after that (2006), hundreds of much better examples were discovered and documented by Andrew Milner in Early Jurassic rocks of southwestern Utah… .” Milner, A.R.C., Lockley, M.R., and Kirkland, J.I. 2006. A large collection of well-preserved theropod dinosaur swim tracks from the Moenave Formation, St. George, Utah. In Harris, J.D., et al. (editors), The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin, 37: 315-328.

p. 44
   “The next year (2007), dinosaur swim tracks were again interpreted from long linear marks on an expansive surface of Early Cretaceous rock in Spain.” Ezquerra, R., Doublet, S., Costeur, L., Galton, P.M., and Pérez-Lorente, F. 2007. Were non-avian theropod dinosaurs able to swim? supportive evidence from an Early Cretaceous trackway, Cameros Basin (La Rioja, Spain). Geology, 35: 507-510.

p. 44
   “In 2013, yet more dinosaur swim tracks were reported from another Early Cretaceous site in Queensland, Australia.” Romilio et al. (2013), and the controversy over this reinterpretation of what was regarded as a “dinosaur stampede” site is taken up in Chapter 3. Also in 2013, yet another example of dinosaur swim tracks was interpreted from China: Xing, L.D., Lockley, M.G., Zhang, J.O., Milner, A.R.C., Klein, H., Li, D.Q., Persons, W.S., and Ebi, J.F. 2013. A new Early Cretaceous dinosaur track assemblage and the first definite non-avian theropod swim trackway from China. Chinese Science Bulletin, 58: 2370-2378.

p. 45
   “Not surprisingly, recreational purposes have never been suggested for swimming dinosaurs, but who knows whether an occasional dip might have also relieved any dinosaurs suffering from skin parasites or a hot day in the Mesozoic.” While hiking by a lake in the Piedmont National Wildlife Refuge in mid-Georgia on a summer day, I was shocked to see a deer swimming vigorously around the lake edge. At some point it came up on the bank, and when I trained my binoculars on it, I could see its body was covered with hundreds of ticks. So it must have been desperate to either get rid of them or to at least feel better. I felt terrible for the deer, but also made a mental note that this was yet another reason why animals that don’t normally swim would get into the water.

p. 46
   “This site has trackways of more than twenty sauropods walking in the same direction and apparently made at about the same time.” Castanera, D., Barco, J., Díaz-Martínez, I., Gascón, J., Pérez-Lorente, F., and Canudo, J. 2011. New evidence of a herd of titanosauriform sauropods from the Lower Berriasian of the Iberian Range (Spain). Palaeogeography, Palaeoclimatology, Palaeoecology, 310: 227-237.

p. 46
   “A Late Jurassic sauropod tracksite near La Junta, Colorado, also shows the tracks of five sauropods moving in the same direction, Price, N.K. 1986. North America’s largest dinosaur trackway site: implications for Morrison Formation paleoecology. Geological Society of America Bulletin, 97: 1163-1176. (2) Lockley (1991).

p. 47
   “The tracksite in the U.K., preserved in Middle Jurassic (about 165 mya) rocks, was likely made by dozens of sauropods moving together… .” Day, J.J., Norman, D.B., Gale, A.S., Upchurch, P., Powell, H.P. 2004. A Middle Jurassic dinosaur trackway site from Oxfordshire, UK. Palaeontology, 47: 319-348.

p. 47
   “These include several sites from the Cretaceous of Korea, one of which has tracks of about twenty large ornithopods heading in the same direction, and another from the Cretaceous of Canada… .” (1) Lockley, M.G., Houck, K., Yang, S.-Y., Matsukawa, M., and Lim, S.-K. 2006. Dinosaur-dominated footprint assemblages from the Cretaceous Jindong Formation, Hallyo Haesang National Park area, Goseong County, South Korea: evidence and implications. Cretaceous Research, 27: 70-101. (2) Currie, P.J. 1983. Hadrosaur trackways from the Lower Cretaceous of Canada. Acta Paleontologica Polonica, 28: 62-74.

p. 47
   “A few ankylosaur tracksites have parallel trackways, suggesting that at least two ankylosaurs were traveling together at the same time.” McCrea et al. (2001).

p. 47
   “Ceratopsian tracks are also uncommon enough to withhold judgment on that aspect of their lives too, although rocks bearing hundreds of bones of the same ceratopsian species tell us these dinosaurs were likely group-oriented also.” (1) Wood, J.M., Thomas, R.G., and Visser, J. 1988. Fluvial processes and vertebrate taphonomy: the upper Cretaceous Judith River Formation, south-central Dinosaur Provincial Park, Alberta, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology, 66: 127-143. (2) Qi, Z., Barrett, P.M., and Eberth, D.A. 2007. Social behaviour and mass mortality in the basal ceratopsian dinosaur Psittacosaurus (Early Cretaceous, People’s Republic of China). Palaeontology, 50: 1023-1029.