Dinosaurs Without Bones (60 page)

p. 151
“Not all paleontologists were so accepting of the idea that dinosaurs were less like reptiles and more like birds… .” Probably no book title of the time summarized those feelings better than this: Thomas, R.D.K., and Olson, E.C. 1980. A Cold Look at the Hot-Blooded Dinosaurs. Westview Press, Boulder, Colorado: 514 p.

p. 151
“With the possible exception of the Allosaurus sp., all of the animals were small enough to have found shelter readily by burrowing.” Quoted from Rich et al. (1988).

p. 155
“For one, the Cretaceous rocks of Victoria abounded with evidence for hypsilophodonts… .” Rich and Vickers-Rich (1999).

p. 155
“For another, such dinosaurs were too small to have migrated long distances between seasons.” Bell, P., and Snively, E. 2008. Polar dinosaurs on parade: a review of dinosaur migration. Alcheringa 32: 271-284.

p. 155
“Thirdly, many modern polar vertebrates, from puffins to polar bears, burrow into dirt or snow to take refuge in those harsh environments.” Davenport, J. 1992. Animal Life at Low Temperatures. Chapman & Hall, London: 246 p.

p. 157
“Gratifyingly, the editor accepted the paper the following week, which had the title… .” Martin (2009). p. 157 “As of this writing, the video had the most views of any in the history of my university, and the press attention was flattering.” The video includes good footage (shot by my wife, Ruth Schowalter) at Knowledge Creek, with me talking about them, at: http://www.youtube. com/watch?v=S8gahKh1l9A

p. 158
“So in an experiment straight out of the popular TV show Mythbusters, Woodruff joined PVC piping… .” Woodruff, D.C., and Varricchio, D.J. 2011. Experimental modeling of a possible Oryctodromeus cubicularis (Dinosauria) burrow. Palaios, 26: 140-151.

p. 159
“… the hypothesis that this Oryctodromeus cubicularis was a burrowing, denning dinosaur still stands.” This hypothesis was further supported in a study done by Jamie Fearon, a graduate student of Varricchio’s. She determined that the forelimb anatomy on Oryctodromeus really was different from that of other ornithopods, and was suited for digging: Fearon, J., and Varricchio, D. 2012. Comparative pectoral and forelimb morphology of Ornithopoda: does Oryctodromeus
cubicularis
exhibit specialization for digging?
Journal of Vertebrate Paleontology
, SVP Program and Abstracts, 2012: 92-93.

CHAPTER 6: BROKEN BONES, TOOTHMARKS, AND MARKS ON TEETH

p. 162
“Although this scenario was imagined, the trace fossil evidence for all such behaviors is real.” (See the references related to this scene under Chapter 1 endnotes.)

p. 163
“Although this ‘skin’ was actually just a natural cast of the original skin, it was closely associated with the bones of
Edmontosaurus annectens.
…” Rothschild, B.M., and Depalma, R. 2013. Skin pathology in the Cretaceous: evidence for probable failed predation in a dinosaur.
Cretaceous Research
, 42: 44-47.

p. 164
“These unusual body fossils were normally formed first as impressions against soft sediment, and then naturally cast in sandstone, similar to how many dinosaur footprints were preserved.” Martin (2006).

p. 166
“Although not all of paleopathology concerns itself with dinosaurs—much of it centers on evidence for diseases in pre-historic human remains—this science is being applied enthusiastically to dinosaurs.” Rega, E. 2012. Disease in dinosaurs.
In
Brett-Surman, M.K., Holtz, T.R., Jr., and Farlow, J.O. (editors),
The Complete Dinosaur
(2nd Edition). Indiana University Press, Bloomington, Indiana: 667-711.

p. 167
“For example, one specimen of
Psittacosaurus
from Early Cretaceous rocks of China also, like the
Edmontosaurus,
has a skin impression associated with its body… .” Lingham-Soliar, T. 2008. A unique cross section through the skin of the dinosaur
Psittacosaursus
from China showing a complex fibre architecture.
Proceedings of the Royal Society of London, B
, 275: 775-780.

p. 168
“(This explanation for how dinosaur parts got into marine sediments is nicknamed the ‘bloat-and-float’ hypothesis.)” Martin (2006).

p. 168
“Amazingly, a few of these bones have toothmarks and embedded teeth from scavenging sharks… .” Schwimmer, D.R. 1997. Late Cretaceous dinosaurs in Eastern USA: a taphonomic and biogeographic model of occurrences. 1997
Dinofest International Proceedings
: 203-211.

p. 168
“Meanwhile on land, lowly mammals imparted their distinctive incisor incisions on a variety of Late Cretaceous dinosaur bones from Alberta, Canada.” Longrich, N.R., and Ryan, M.J. 2010. Mammalian tooth marks on the bones of dinosaurs and other Late Cretaceous vertebrates.
Palaeontology
, 53: 703-709.

p. 168
“Carrion beetles, which dine on dead bodies, or termites, which make small pits or tunnels in bones, could have made these.” (1) Britt, B.B., Scheetz, R.D., and Dangerfield, A. 2008. A suite of dermestid beetle traces on dinosaur bone from the Upper Jurassic Morrison Formation,
Wyoming, USA.
Ichnos
, 15: 59-71. (2) Xing, L., Roberts, E.M., Harris, J.D., Gingras, M.K., Ran, H., Zhang, J., Xu, X., Burns, M.E., and Dong, Z. 2013. Novel insect traces on a dinosaur skeleton from the Lower Jurassic Lufeng Formation of China.
Palaeogeography
,
Palaeoclimatology
,
Palaeoecology
, 388: 58-68.

p. 169
“Among my favorite examples of these are big holes in the head shields of
Triceratops
. When paleontologists first noticed these holes, they were a bit mystified.” Farke
et al.
(2009).

p. 169
“So paleontologists Andrew Farke, Ewan Wolffe, and Darren Tanke, in an attempt to make sense of these holes, took a closer look at the sizes, shapes, and placements of them… .” Farke
et al.
(2009).

p. 170
“As many dinosaur fans can relate … the genus name
Triceratops
, assigned in 1889, translates as ‘three-horned face.’” Marsh, O.C. 1889. Notice of gigantic horned Dinosauria from the Cretaceous.
American Journal of Science
, 38: 173-175.

p. 170
“Paleontologists are also now sure that
Triceratops
horns changed in size and shape throughout their lives, becoming more formidable with age.” Horner, J.R., and Lamm, E. 2011. Ontogeny of the parietal frill of
Triceratops
: a preliminary histological analysis.
Comptes Rendus Palevol
, 10: 439-452.

p. 171
“Paleontological artist Charles Knight (1874–1953) most famously depicted such a scenario in a 1927 mural… .” Simply titled
Tyrannosaurus and Triceratops
, it is probably the most iconic of Knight’s gorgeous and influential artworks, and the original is in the Field Museum of Natural History in Chicago, Illinois: http://www. charlesrknight.com/Enlarge.htm?109

p. 171
“Only one tantalizing
Triceratops
skull tells of a living battle with a
Tyrannosaurus
, in which one of its brow horns and a squamosal bone were chomped and later healed.” Happ, J. 2008. An analysis of predator-prey behavior in a head-to-head encounter between
Tyrannosaurus rex
and
Triceratops
.
In
Larson, P., and Carpenter, K. (editors).
Tyrannosaurus rex, the Tyrant King
. Indiana University Press, Bloomington, Indiana: 355-368.

p. 172
“In this role, their large heads would have been quite useful for recognizing the same species and perhaps gender… .” Padian, K., and Horner, J.R. 2011. The evolution of ‘bizarre structures’ in dinosaurs: biomechanics, sexual selection, social selection or species recognition?
Journal of Zoology
283: 3-17.

p. 172
“Pachycephalosaurs, such as
Pachycephalosaurus
,
Stegoceras
, and others, are relatively rare dinosaurs and only found in Cretaceous Period rocks.” (1) Makovicky, P. 2012. Marginocephalia.
In
Brett-Surman, M.K., Holtz, T.R., Jr., and Farlow, J.O. (editors),
The Complete Dinosaur
(2nd Edition). Indiana University Press, Bloomington, Indiana: 527-549. (2) Maryańska, T., Chapman, R.E., and Weishampel, D.B. 2004. Pachycephalosauria.
In
Weishampel, D.B., Dodson, P., and OsmoÅLlska, H. (editors),
The Dinosauria
(2nd Edition). University of California Press, Berkeley, California: 464-477.

p. 172
“These skullcaps … can be nearly 25 cm (10 in) thick. They are composed of parietals and closely associated skull bones… .” Makovicky (2012).

p. 173
“Nearly everybody agrees that these robust skulls must have been used for butting… .” Makovicky (2012).

p. 174
“In 2011, two paleontologists, Eric Snively and Jessica Theodor, had head-butting in mind… .” Snively, E., and Theodor, J.M. 2011. Common functional correlates of head-strike behavior in the pachycephalosaur
Stegoceras validum
(Ornithischia, Dinosauria) and combative artiodactyls.
PLoS ONE
6(6): e21422. doi:10.1371/journal. pone.0021422.

p. 174
“They then repeated their analysis on three species of modern mammals that habitually head-smash one another… .” Snively and Theodor (2011).

p. 175
“In 2012 … two other paleontologists—Joseph Peterson and Christopher Vittore—scrutinized a
Pachycephalosaurus
skull… .” Peterson, J., and Vittore, C. 2012. Cranial pathologies in a specimen of
Pachycephalosaurus
.
PLoS ONE,
7(4): doi: 10.1371/journal.pone.0036227.

p. 176
“In a follow-up study published in 2013, Peterson and two other paleontologists found many more examples, verifying the previous study.” Peterson, J.E., Dischler, C., and Longrich, N.R. 2013. Distributions of cranial pathologies provide evidence for head-butting in dome-headed dinosaurs (Pachycephalosauridae).
PLoS ONE
8(7): e68620; doi: 10.1371/journal.pone.0068620.

p. 176
“One is of injured but healed bony tissue in a few tail spikes of
Stegosaurus
.” Carpenter, K., Sanders, F., McWhinney, L.A., and Wood, L. 2005. Evidence for predator-prey relationships: examples for
Allosaurus
and
Stegosaurus
.
In
Carpenter, K. (editor),
The Carnivorous Dinosaurs
. Indiana University Press, Bloomington, Indiana: 325-350.

p. 177
“Another is of a hole in a tail vertebra of an
Allosaurus
, but one that probably healed around a piece of a
Stegosaurus
tail spike, an unwanted souvenir.” Carpenter
et al.
(2005).

p. 177
“Paleontologists … had figured that stegosaur tail spikes were used for self-defense, but lacked further confirmation until … 2001 (broken spikes) and 2005 (a healed hole in the bone of a predator).” McWhinney, L.A., Rothschild, B.M., and Carpenter, K. 2001. Posttraumatic chronic osteomyelitis in
Stegosaurus
dermal spikes.
In
Carpenter, K. (editor).
The Armored Dinosaurs
. Indiana University Press, Bloomington, Indiana: 141-156.

p. 177
“Nicknamed ‘Big Al’ and studied by paleontologist Rebecca Hanna in the 1990s, this
Allosaurus
was unusual in two ways… .” Hanna began reporting on “Big Al” in the late 1990s at professional meetings, and the full results were summarized in her 2002 paper: Hanna, R.R. (2002). Multiple injury and infection in a sub-adult theropod dinosaur (
Allosaurus fragilis
) with comparisons to allosaur pathology in the Cleveland-Lloyd Dinosaur Quarry Collection.
Journal of Vertebrate Paleontology
, 22: 76-90. I also recommend checking out a still-informative and entertaining BBC documentary featuring Hanna talking about this
Allosaurus
, initially titled
The Ballad of Big Al
(2000).

p. 177
“One of the reasons for this may be an easy one:
Coelophysis
was a much smaller dinosaur than
Allosaurus.
…” Holtz
et al.
(2012).

p. 178
“As elaborated in a previous chapter, if a large two-legged dinosaur tripped, both its greater weight and height would conspire against it… .” Farlow
et al.
(1995).

p. 180
“For example, a few smaller theropods, such as the Late Cretaceous theropods
Velociraptor
and
Saurornitholestes
, had thin, curved, and beautifully serrated teeth.” A good summary of theropod tooth shapes and their inferred functions is in: Fastovsky, D.E., and Weishampel, D.B. 2009.
Dinosaurs: A Concise Natural History
. Cambridge University Press, Cambridge, U.K.: 379 p.

p. 180
“Tooth forms even varied within the same dinosaur, a condition called heterodonty (‘different teeth’).” Martin (2006).

p. 181
“But if you looked deeper into its mouth, say, while being eaten, you would see that the teeth in the front curve more toward the rear of the mouth… .” Reichel, M. 2012. The variation of angles between anterior and posterior carinae of tyrannosaurid teeth.
Canadian Journal of Earth Sciences
, 49: 477-491.

p. 181
“Certain theropods had an exact number of teeth per tooth row, but that number could also be divided into two parts… .” Reichel (2012).

p. 182
“These marks would have been made by a pulling, lateral movement, so they would be shallow, long grooves on a bone surface… .” Jacobsen, A.R., and Bromley, R.G. 2009. New ichnotaxa based on tooth impressions on dinosaur and whale bones.
Geological Quarterly
, 53: 373-382.

p. 182
“Because this action would have been more perpendicular to the bone surface, these puncture toothmarks will be deeper… .” Jacobsen, A.R. 1998. Feeding behaviour of carnivorous dinosaurs as determined by tooth marks on dinosaur bones.
Historical Biology
, 13: 17-26.

p. 182
“Although dinosaur toothmarks were first interpreted as trace fossils near the start of the 20th century… .” Matthew, W.D. 1908.
Allosaurus
, a carnivorous dinosaur and its prey.
American Museum Journal
, 8: 2-5.