Unearthing the Anatomy of Dinosaurs. New Insights Into Their Functional Morphology and Paleobiology. The Anatomical Record. Special Issue

288 Pages·2009·23.75 MB·English

by  Dodson P.

THEANATOMICALRECORD292:1235–1236(2009)
EDITORIAL
Dinosaurs and Their Relatives
are Alive and Well in
The Anatomical Record
Anatomists and dinosaurs have a long and anatomist and fossil doyen Peter Dodson (Dodson,
entwined history. For example, some readers of this 2009), like Leidy a denizen of the University of Penn-
journal—and members of its parent association, The sylvania, represents a natural next step for the
American Association of Anatomists—may be sur- presentation of dinosaur science in The Anatomical
prised to learn that the paterfamilias of the Associa- Record. This extraordinary issue is a cornucopia of
tion and its first president was the great anatomist the finest, most insightful, anatomical-based research
and paleontologist, Joseph Leidy of the University of that seeks to unshroud and re-create these magnifi-
Pennsylvania. Indeed, Leidy was the first to describe cent creatures and their world. It seems most fitting
fossil dinosaurs found in the Americas and set the that the society whose first leader was the initial
stage for Edward Drinker Cope and Othniel C. describer of dinosaurs on this continent would now
Marsh, the famed ‘‘dinosaur hunters’’ of the late 19th have its premier journal serve as the home for the
century, to make their mark (see Laitman, 2009). leading investigations on their anatomy, function, and
Ever since, these mysterious and wondrous beasts of paleobiology. So, to Tyrannosaurus, Hadrosaurus,
the far distant past, with names we love to say yet of- Velociraptor, Ankylosaurus, Diplodocus, and beloved
ten can barely pronounce and even fewer can spell Brontosauruses everywhere, The Anatomical Record
correctly, have held the greatest fascination for lay- says ahearty,‘‘welcomehome!’’
manand scientist alike—though they’vebeen gonefor
60million years,give ortake afewmillion!
While The Anatomical Record has been the home
Jeffrey T. Laitman*
overtheyearsforanassortmentofstudiesthroughthe Associate Editor
anatomist’s prism on aspects of vertebrate paleontol- TheAnatomical Record
ogy,includingthoserelatingtodinosaursandtheirkin
(e.g., Shaner, 1926), the last 5 years alone have seen
KurtH.Albertine
our journal become increasingly the voice for a robust Editor-in-Chief
herd of the best and brightest hypothesis-driven sci- TheAnatomical Record
ence that explores the anatomy and biology of dino-
saursandtheirworld.Ithas,indeed,beenourpleasure
to watch as those using cutting-edge techniques, tech-
LITERATURE CITED
nologies, and integrative approaches have come to our
journal to present their dynamic science and creative BonanMF.2007.Linearandgeometricmorphometricanalysisof
ideas.Fromin-depthperspectivesusingbiomechanical longbone scaling patterns in Jurassic neosauropod dinosaurs:
models (e.g., Preuschoft and Witzel, 2005; Rayfield, their functional and paleobiological implications. Anat Rec
2005; Ross, 2005; Witzel and Preuschoft, 2005; 290:1089–1111.
Dodson P. 2003. Allure of El Largeto—why do dinosaur paleon-
McHenry et al., 2006; Bonan, 2007; Nummela et al.,
tologists love alligators, crocodiles and their kin? Anat Rec A
2007)tometiculousre-creationsofstructureandfunc-
274:887–880.
tion based upon comparative anatomical assessments
Dodson P. 2009. Dinosaurs in the year of Darwin. Overview of
(e.g.,Meers,2003;Dodson,2003;Organ,2006;Schwarz the special issue, ‘‘Unearthing the anatomy of dinosaurs: new
et al., 2007; Snively, 2007; Witmer and Ridgely, 2008), insights into their functional morphology and paleobiology.
to new approaches in discovering ancient dinosaur AnatRec292:1240–1245.
pathologies (e.g., Witzmann et al., 2008), to insights Harris JD. 2004. Confusing dinosaurs with mammals: tetrapod
and new interpretations on taxonomy and system- phylogenetics and anatomical terminology in the world of
atics (e.g., Harris, 2004; Smith et al., 2005), the homology.AnatRecA281:1240–1246.
Laitman JT. 2009. The real Jurassic Park: Joseph Leidy’s heirs
dinosaurian world has begun to unfurl within our
econstructtheanatomyofdinosaurs.AnatRec292:1237–1239.
journal’spages.
McHenry CR, Clausen PD, Daniel WJT, Meers M, Pendharkar
This month’s Special Issue, ‘‘Unearthing the Anat-
A. 2006. Biomechanics of the rostrum in crocodilians: a com-
omyofDinosaurs:New InsightsIntoTheirFunctional parative analysis using finite-element modeling. Anat Rec A
MorphologyandPaleobiology,’’guesteditedbyrenown 288:827–849.
(cid:1)2009 WILEY-LISS, INC.
1236 EDITORIAL
Meers M. 2003. Crocodylian forelimb musculature and its rele- Snively E. 2007. Functional variation in the neck muscles and
vancetoArchosauria.AnatRecA274:891–917. their relation to feeding style in Tyrannosauridae and other
Nummela S, Thewissen JGM, Bajpai S, Hussain T, Kumar K. largeTheropoddinosaurs.AnatRec290:934–957.
2007.Soundtransmissioninarchaicandmodernwhales:ana- Witmer LM, Ridgely RC. 2008. The paranasal air sinuses of
tomical adaptations for underwater hearing. Anat Rec 290: predatory and armored dinosaurs (Archosauria: Theropoda
716–733. andAnkylosauria)andtheircontributiontocephalicstructure.
Organ CL. 2006. Thoracic epaxial musculature in living AnatRec291:1362–1388.
archosaurs and ornithopod dinosaurs. Anat Rec A 288: WitzelU,PreuschoftH.2005.Finite-elementmodelconstruction
782–793. for the virtual synthesis of the skulls of vertebrates: case
Preuschoft H, Witzel U. 2005. Functional shape of the skull in studyof Diplodocus.AnatRecA283:391–401.
vertebrates:whichforcesdetermineskullmorphologyinlower WitzmannF,AsbachP,RemesK,HampeO,HilgerA,PaulkeA.
primatesandsynapsids?AnatRecA283:402–413. 2008.Verticalpathologyinanornithopoddinosaur:ahemiver-
Rayfield EJ. 2005. Using finite-element analysis to investigate tebra in Dysalotosaurus lettowvorbecki from the Jurassic of
suturemorphology:acasestudyusinglargecarnivorousdino- Tanzania.AnatRec291:1149–1155.
saurs.AnatRecA283:349–365.
Ross CF. 2005. Finite element analysis in vertebrate biome-
chanics.AnatRecA283:253–258.
*Correspondence to: Jeffrey T. Laitman, Center for Anat-
SchwarzD,FreyE,MeyerCA.2007.Novelreconstructionofthe
omy and Functional Morphology, Box 1007, Mount Sinai
orientation of the pectoral girdle in Sauropods. Anat Rec
SchoolofMedicine,NewYork,NY10029.Fax:[phone];
290:32–47.
E-mail:[email protected]
Smith JB, Vann DR, Dodson P. 2005. Dental morphology
andvariationintheropoddinosaurs:implicationsforthetaxonomic Received14July2009;Accepted14July2009
identificationofisolatedteeth.AnatRecA285:699–736. DOI10.1002/ar.21004
ShanerRF.1926.Thedevelopmentoftheskulloftheturtle,with PublishedonlineinWiley InterScience(www.interscience.wiley.
remarksonfossilreptileskulls.AnatRec32:343–367. com).
THEANATOMICALRECORD292:1237–1239(2009)
The Real Jurassic Park:
Joseph Leidy’s Heirs Reconstruct
the Anatomy of Dinosaurs
JEFFREY T. LAITMAN*
AssociateEditor, TheAnatomicalRecord
Locust Walk at the University of Pennsylvania is ‘‘Unearthing the Anatomy of Dinosaurs: New insights
amongst the most beautiful college streets in America. into their Functional Morphology and Paleobiology’’
As I strolled there a few weeks back with Peter Dodson, (Dodson,2009a)?Allthis needsalittleexplaining.
the Guest Editor of this Special Issue and one of the In our world today, dinosaurs are again kings of the
great professors of that venerable institution, I could not planet, at least in terms of which beasties fascinate the
help but imbibe the energy of the students around us public. Who amongst us did not as a child have a plastic
mixed with the sweetness of the late spring air. As I had T-Rex or Brontosaurus (I know, I know, it’s the wrong
since we first met at Yale around our Anatomy dissect- name now, but Apatosaurus just won’t work for anyone
ing table in the fall of 1973, I listened attentively to who doesn’t live in a museum)? Whenever I work at the
Peter, enraptured by his energetic wealth of knowledge. American Museum of NaturalHistory here in NewYork,
As anyone who has taken anatomy knows, you always I have to push through the throngs of school children
remember your dissection tablemates, and Peter is clamoring to see our assortment of Jurassic meat-eaters
indeed memorable. At the time we met, I was a trem- and Cretaceous vegetarians with names they gleefully
bling, beginning graduate student and Peter an already try to pronounce with a combination of amazement and
wizened warrior finalizing his dissertation. As he joy. If one looks carefully, one can even see how different
showed me how to correctly load the scalpels (and personality types radiate to different dinosaurs: the
always helped me with the band-aids I would need when aggressive kids run to Tyrannosaurus; the mischievous
I missed) he would wax eloquently about ceratopsian ones love Velociraptor; the thoughtful ones ponder the
dinosaurs, interpreting fossil remains, and reconstruct- horned dinosaurs; the kids with the pocket-protectors
ing phylogenies all interspersed with our more mundane love the odd-looking duck-billed hadrosaurs; the vegeta-
daily chores around the cadaver. He was both a role rians, gentle souls, and chubby kids, make a direct path
modeland amentor,andIappreciativelyfollowedalong. to the brontos (I loved the brontos; indeed, my first time
Now, as then, I followed his lead, and that led to a being ejected from the museum was due to climbing on
reddish building just off the Walk known as The Wistar one.) Dinosaurs are part of our 21st century culture, as
Institute of Anatomy. ‘‘Why are we stopping here?’’ I alive today as when they thumped across the earth mil-
asked,alittleperturbed,anever-compulsiveNewYorker lennia ago.
eager to get to our work, the precious trove of manu- It is a little difficult to fathom a world in which dino-
scripts waiting on us in his lab. ‘‘I’d like to see if we can saurs were not part of our imagination. They are, how-
visit Professor Leidy,’’ Peter answered, ‘‘it would be most ever, actually a relatively recent part of our vernacular.
appropriate.’’ ‘‘Wow, Joseph Leidy has a descendant now Indeed, the ‘‘Dinosauria’’ (meaning ‘‘terrible lizards’’)
at Penn?’’ I asked incredulously. ‘‘No,’’ he answered, ‘‘his were only first named as such in 1842 by the great Brit-
brainishere.’’ ish anatomist and paleontologist Richard Owen (1842).
As it turned out, while the great Professor’s brain was He included in this the few extinct ‘‘reptile-like’’ fossils
indeed in residence, we had not made an ‘‘appointment’’ that had been found previously, notably the Reverend
and so he (it?) could not receive us, we were duly William Buckland’s Megalosauraus (arguably, the first
informedbytheguardianwhocametoexplain.Although ‘‘dinosaur’’ discovered in 1824) and the remains of Igua-
Peter implored that we were his academic ‘‘relatives’’ nodon and Hyaeosaurus, described by Gideon Mantrell
and I chimed in to suggest he (it?) would be pleased to in 1825 and 1833 (Buckland, 1824; Mantrell, 1825; see
see us (I should have been quiet as this didn’t help; we Dodson, 2009b, for discussion). So, with the insight and
got a stern and odd look), she was adamant that we wisdom of the great anatomist Owen, dinosaurs took
would need to make an official request much further in their first thunderous steps. A little over a decade later
advance.TheProfessordidnotreceive‘‘dropin’’visitors.
Although our pilgrimage was not successful on that
day, we are making our plans to return, and will request *Correspondence to: Jeffrey T. Laitman, Centerfor Anatomy
an appointment appropriately far in advance (just as andFunctionalMorphology,Box1007,MountSinaiSchoolofMedi-
well, as I’d like to be better dressed than I was to meet cine,NewYork,NY10029.E-mail:[email protected]
The Professor.) But, you may ask, why the visit in the Received17June2009;Accepted18June2009
first place, why was the brain of this man preserved, DOI10.1002/ar.20993
and who was Joseph Leidy, anyway, and what were his Published online in Wiley InterScience (www.interscience.wiley.
ties to anatomy, dinosaurs, or this Special Issue, com).
VVC 2009WILEY-LISS,INC.
1238 LAITMAN*
they were ‘‘brought to life’’ in the famous reconstructions otal at the outset (he published about 230 papers on
by Benjamin Waterhouse Hawkins (under Owen’s guid- paleontology, Warren, 1999)—changed radically and,
ance) at the Crystal Palace exhibition of 1854 in Syden- largely, by his own choice. This was mostly due to the
ham, England. One can only imagine the awestruck ‘‘tone’’ that dinosaur paleontology gradually accrued to
crowds that viewed these great, towering, mega-lizards itself in the 1870s and 1880s—a fiery, combative, and
ofthelong-distantpast! combustible cacophony that was more and more
By the mid 19th century, dinosaurs had thus been unsuited to the scholarly, genteel, multidimensional,
hatched, so to speak, but certainly were not the subject Renaissance man from the City of Brotherly Love. This
of everyday conversation, particularly on this side of the tone was set in place due to a rivalry between two
pond. That would start to change in 1856, when our men—Othniel C. Marsh and Edward Drinker Cope—
Professor Leidy—the ‘‘brain’’ we went to see—would that was arguably amongst the most angry and vitriolic
describe the first American dinosaurs from fossil teeth in thehistory ofscience(seeShor,1974;Hellman,2007).
sent to him from deposits along the Missouri River in The seemingly never ending battles between Marsh
present-day Montana. Here is where Leidy enters the and Cope increased in intensity during the last quarter
story. The material was sent to him, as Joseph Leidy of the 19th century as each sought pre-eminence in the
(1823–1891) was arguably the preeminent scientist of burgeoning field of paleontology. Cope was a Pennsylva-
the middle part of the 19th century. He was the 19th nia product who studied anatomy under Leidy and even-
century version of da Vinci, a man whose scope of exper- tuallyassumedLeidy’sChairin zoologyand comparative
tise was so truly extensive that his recent biographer, anatomy at Penn toward the end of his life; Marsh was
Leonard Warren, titled his book, The Last Man who a Yale graduate who was blessed with a rich uncle,
Knew Everything (Warren, 1999). The regal Professor of George Peabody, who largely effectuated his being
Anatomy at the University of Pennsylvania (which he named as the nation’s first Professor of Paleontology at
would hold for almost 40 years), trained as a physician, Yale. For most of the latter part of the 19th century, di-
with knowledge (and many publications) in fields rang- nosaur studies in the UnitedStatesrevolved around this
ing from gross anatomy, to microscopy, to parasitology, Yale/Penn axis, with Cope and Marsh gaining near
to protozoology, to paleontology. The Professor reigned Olympian stature, as Leidy, the great Titan of old, with-
supreme. Indeed, when the American Association of drew from the battles. The gentle, sweet-natured, schol-
Anatomists—the parent body of this august journal— arly man of the dissecting lab and microscope, could not,
was founded in 1888 (as the Association of American would not, compete with often ill-tempered, tabloid-hun-
Anatomists), Leidy was chosen in absentia as its first gry prima donnas that would pay hefty amounts for ev-
president. (Basmajian, 1987; Clemente, 1987). It is what ery fossil the Wild West gave up. He withdrew from the
my kids would call a ‘‘no brainer;’’ JL (nice initials) was fray, returning to the scholarly pursuits and teaching he
unquestionably the man. Thus, it was no surprise that if wasmorecomfortablein.
one wanted to know what some interesting old bones Part of the sadness of this tale is that while Leidy
were, they would send them to the great Professor. (To largely set the stage for our knowledge of dinosaurs, he
answer one of my above questions, it was the custom in and his accomplishments were essentially ignored by the
the 19th century to preserve the brain of a great ‘‘mind,’’ egomaniacal appetites of Cope and Marsh. Indeed, most
for example, Paul Broca’s is similarly honored in the of the fossils that were named by Leidy were renamed
Musee de l’Homme in Paris; when my teenage daughter by Cope and Marsh (at one time, there were three
asked me what I was writing about, and I explained the names for each species!) In speaking of the above ‘‘bur-
above, she looked at me, patted me on the head and ial’’ of the findings and accomplishments of Leidy by
said,‘‘don’tworryDad,yoursissafe.’’) Cope and Marsh, the famous early 20th century paleon-
Although Leidy recognized the teeth he had received tologist and future President of The American Museum
as belonging to extinct reptiles of various types, and of Natural History, Henry Fairfield Osborn, simply and
named them scientifically (Deinodon, Trachodon, Troo- clearly noted in a presentation honoring Leidy: ‘‘I am
don, Palaeoscincus), they were not monumentally impor- not quite sure, but I doubt if you will find in the writ-
tant specimens, save for the historical nature of their ings of Professor Cope or Professor Marsh a single allu-
being the first. A few years later, however, Leidy was sion to the work of Leidy’’ (Osborne, 1923; also see
brought material unearthed from—of all places—New Warren, 1999 for full discussion). Not only were Cope
Jersey (more famous in our time for burying the occa- and Marsh gluttonous carnivores in their quest for
sional vertebrate). This was a marvelous, and extensive, bones, they were equally rapacious in devouring the
collection of cranial and postcranial bones that Leidy memoryofthemanwhomadetheirworkpossible.
anointed as Hadrosaurus—the extraordinary-looking Thus, my focus here on Joseph Leidy, arguably the
duck-billed dinosaur. He estimated it to be 25-feet long mostimportant,learned,honored,andleastremembered
and, based upon its small forelimbs and long hind limbs, great man of 19th century science, and the person who
reconstructed it in a ‘‘kangaroo-like’’ stance, with semi- truly birthed the anatomical study of dinosaurs on this
upright posture (Leidy, 1858, 1865; Dodson, 2009b). The continent. It is fitting that his name be honored, and his
vertical ‘‘dinosaur’’ of our imagination was thus born story retold, in this Special Issue. Peter Dodson, our
and, when it was given life at the Academy of Natural Guest Editor, is in many ways a true heir and descend-
Science in Philadelphia in 1868 in the first museum dis- ant of the great man: like Leidy, a Penn Professor, anat-
play of any dinosaur, our image of dinosaurs that ligers omist, multidimensional scholar, extraordinary teacher
tothepresent begantotakeshape. and raconteur, and a gentleman of the old school (put up
As the world of the dinosaurs began to gradually with me, didn’t he?). In this Issue, Dodson has used his
emerge, the American West became the epicenter of own gravitas as a doyen of the field (he is the shepherd
extraordinary finds. Interestingly, Leidy’s role—so piv- of all horned dinosaurs, e.g., Dodson, 1996, as well as a
THEREALJURASSICPARK 1239
historian and interpreter of the field, e.g., Dodson, 2008, their paleontologist’s flair for the drama of obtaining
2009b,c) to pull together a wonderful and varied herd of materialandtheaccompanyingpublicglorythatensued,
dinosaur anatomists who have collectively worked mayhavedonemuchtocapturethecountry’sfascination
together to yield a rich volume of the state-of-the-art with dinosaurs, it was Leidy who set the early bar for
knowledge of dinosaur form, function, behavior, and the scholarship and science of the anatomical interpreta-
evolution. Within this collection, a number of varying tion of dinosaurs. Simply put, where Leidy was all about
dinosaur groups come under the paleontological scalpel, the science of dinosaurs, for Marsh and Cope it at times
including, the well-known tyrannosaurs, the duck-billed took a far second behind the glitz and glamor of recogni-
hadrosaurs (first recognized by Leidy), the horned cera- tionand adulation.
topsians, herbivorous groups like the club-tailed ankylo- As demonstrated in this Special Issue, Dodson and his
saurids,tothecurrent‘‘rockstars’’ofthedinosaurworld, like-minded brethren have clearly taken up the mantle
the velociraptors. As varied as the groups are, so too are in thesearchtounderstandthesciencebehindtheworld
theregionsstudiedwithnooksandcranniesfromheadto of the dinosaurs; they are the true heirs of Joseph Leidy.
clawedtoebeingexamined.Forthoseofyou,likeme,who Indeed, I think the Professor would be most pleased by
are not cognoscenti of dinosaur anatomy, studies deci- the work his offspring have produced, and look forward
phering the functional anatomy of an array of horns, to bringing a copy as a gift when Peter and I visit him
claws,specializedteeth,cranialcrests,tailclubs,andthe on mynexttriptoPenn.
like, will remind us to why we radiated to the dinosaur
hallsinthemuseumsinthefirstplace.Thesearewonder-
fulandwondrousthingstobehold!
LITERATURE CITED
A theme that winds through many of the studies—and
will resonate withreadersofthis journal—is the hypoth- BasmajianJV.1987.Theearlyyears.In:PaulyJ,editor.TheAmer-
esis-driven science that drives many of the approaches. ican Association of Anatomists, 1888–1987: essays on the history
Elegant tests aboundto explorearangeoftopics, includ- of anatomy in America and a report on the membership—past
ing: how to reconstruct jaw muscle anatomy, the anat- andpresent.Baltimore:Williams&Wilkins.p3–14.
omy underlying sensory organization and behavior, bone BucklandW.1824.NoticeontheMagalosaurusorgreatfossillizard
ofStonesfield.TransGeolSocLondSer21:390–396.
strength as it effects posture and locomotion, the use of
ClementeCD. 1987. Gross anatomy: contributions of five American
extant species of birds as experimental models of bone
anatomistsduringthefirstcenturyoftheassociation.In:PaulyJ,
structure in dinosaurs, new methods of bone surface
editor.TheAmericanAssociationofAnatomists,1888–1987:essays
texture as indicators of dinosaur aging, and the use of onthehistoryofanatomyinAmericaandareportonthemember-
skeletal markers as an aid in determining respiratory ship—past and present. Baltimore: Williams & Wilkins. p 148–
biology and behaviors. Most impressive as well are the 163.
range of cutting-edge approaches and techniques that Dodson P. 1996. The horned dinosaurs. Princeton, NJ: Princeton
are usedto extract information from the otherwise silent UniversityPress.
bones, such as computational modeling, finite-element DodsonP.2008.Yourinnerdinosaur.AmPaleontol16:33–36.
Dodson P. 2009a. Dinosaurs in the year of Darwin. Anat Rec
analysis, and advanced CTanalysis. Lastly, but far from
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least, while the core of the special issue revolves about
DodsonP.2009b.DinosaursinAmerica—JosephLeidy&theAcad-
deciphering the functional anatomy of dinosaurs, consid-
emyofNaturalSciences.AmPaleontol17:31–35.
erable insights on behavior patterns, lifestyles, and pop- DodsonP.2009c.Darwinandthedinosaurs.AmPaleontol17:33–36.
ulationbiologypermeatemanystudies. Hellman H. 2007. Great feuds in science. New York: Barnes &
As a graduate student at Yale, I became very familiar Noble.
with the finds of Marsh (filling every shelf of the Pea- Leidy J. 1858. Remarks concerning Hadrosaurus. Proc Acad Nat
body—his uncle George’s—Museum there) as well as the Sci(Phila)10:215–218.
work of his hated competitor Cope (a large part of whose Leidy J.1865.Memoir oftheextinct reptiles ofthe Cretaceous for-
mationsoftheUnitedStates.SmithContribKnowl14:1–135.
collection was sold to the American Museum of Natural
Mantrell GA. 1825. Notice on the Iguanodon, a newly discovered
History in New York; see Preston, 1986). Like most
fossilreptilefromtheSandstoneofTilgateForest,inSussex.Phil
other young students, they were the names that we
TransRSoc115:179–186.
were weaned on, the names on the fossils sleeping on OsborneHF.1923. JosephLeidy,founderofvertebratepaleontology
every dusty shelf. It was only when I began to dig inAmerica.In:LeidyCommemorativeMeeting,AcademyofNatu-
deeper into the core of the science (after actually listen- ralSciences,Philadelphia,PA,December6,1923.
ing a bit to Peter and getting more interested in the Owen R. 1842. Report on British fossil reptiles. Part II. Report Br
strange beasts he clamored on about) did I start to find, AssocAdvSci11:60–204.
and then appreciate the work of Leidy. Even as a bud- Preston DJ. 1986. Dinosaurs in the attic: an excursion into the
American Museum of Natural History. New York: St. Martin’s
ding anatomist, I could appreciate the meticulousness of
Press.
his science, his descriptions, comparative anatomical
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perspective, and understanding of functional underpin-
Hicksville,NY:Exposition-UniversityPress.
nings, aspects that I at times found wanting in the Warren L. 1999. Joseph Leidy: the last man who knew everything.
tomes of Marsh or Cope. While Marsh and Cope, with NewHaven:YaleUniversityPress.
THEANATOMICALRECORD292:1240–1245(2009)
Dinosaurs in the Year of Darwin
PETERDODSON1,2*
1DepartmentofAnimalBiology, School ofVeterinary Medicine, Universityof
Pennsylvania, Philadelphia, Pennsylvania
2DepartmentofEarthand EnvironmentalScience,School ofArts andSciences, University
ofPennsylvania,Philadelphia, Pennsylvania
ABSTRACT
This special issue of The Anatomical Record explores the recent
advances in the functional morphology and paleobiology of dinosaurs.
Although Darwin did not study dinosaurs because paleontology was in its
infancyacenturyand halfago,heconsideredbothpaleontologyand anat-
omy as essential subjects for establishing the validity of evolution. The
study of dinosaurs constitutes a vigorous subdiscipline within vertebrate
paleontology, and anatomists and evolutionary functional morphologists
constitute an especially creative subgroup within dinosaur paleontology.
The collection of 17 papers presented in this issue encompass cranial
anatomy, postcranial anatomy, and paleobiology of dinosaurs and other
archosaurs. Soft tissue subjects include studies of brain structure, jaw
adductor muscles, and keratinous appendages of the skull. Taxonomically,
it includes four papers with a focus on theropods, including Tyrannosau-
rus, five papers dealing with ceratopsians, three papers on hadrosaurs,
and one on ankylosaurs. Modern anatomical techniques such as CTscan-
ning, finite element analysis, and high resolution histology are empha-
sized. The visual presentation of results of these studies is spectacular.
Results include the first-ever life history table of a plant-eating dinosaur;
a determination of the head orientation of Tyrannosaurus and its rela-
tives based on interpretation of the semicircular canals. The claws of
Velociraptor appear to best adapted for tree climbing, but not for horrific
predatory activities. Pachyrhinosaurus evidently used its massive head
for head butting. The tail club of the armored dinosaur Euoplocephalus
had the structural integrity to be used as a weapon. The pages abound
withinsights such asthese. Dinosaurs once dead formillionsof years live
again!AnatRec, 292:1240–1245,2009.VVC 2009Wiley-Liss, Inc.
Keywords: dinosaurs; functional morphology; paleobiology
How fitting this year as we bask in the warm glow of amount to anything. He studied botany at Cambridge
the Darwin anniversaries. On February 12, 2009, we with John Stevens Henslow, a cherished mentor. He
were blessed with the 200th anniversary of the birth of came late to geology, taking a field trip to Wales with
Charles Darwin, and November 22, 2009 marks the Adam Sedgwick after he graduated in 1831. He was pre-
150th anniversary of the publication of On the Origin of paring for a career in the ministry and intended to live
Species. The gentle Darwin possessed one of the great the life of a country parson, a leisurely life that would
intellects of the 19th century, and probably of all time. A afford ample opportunity for indulging his passion for
prolific writer, the facts of Darwin’s life are well known
and thoroughly documented (Desmond and Moore, 1991;
*Correspondence to: Peter Dodson, Department of Animal
Browne, 1995, 2002). Darwin was a failed medical stu-
Biology,SchoolofVeterinaryMedicine,UniversityofPennsylva-
dent at Edinburgh, disliking anatomy (perish the nia,Philadelphia,PA19104-6045.
thought!) and despising surgery, as would any sensitive E-mail:[email protected]
person in those gruesome days before anesthesia. Received23June2009;Accepted23June2009
Always an enthusiastic field naturalist, he spent his
DOI10.1002/ar.20981
days at Cambridge collecting insects, riding, and shoot- Published online in Wiley InterScience (www.interscience.wiley.
ing; his physician father despaired that he would com).
VVC 2009WILEY-LISS,INC.
DINOSAURSINTHEYEAROFDARWIN 1241
natural history. Henslow, however, nominated young For our part, those subjects of greatest interest are
Darwin for a 2-year voyage on HMS Beagle with Cap- the anatomy and paleontology of dinosaurs. Ironically,
tainRobertFitzRoy.Theintended2-yearvoyagestretched Darwin made an impact as a collector of fossils on his
to a 5-year circumnavigation of the globe. Darwin was a great voyage. Most famous are the Plio-Pleistocene
terrible sailor and never grew accustomed to the rolling mammals that Darwin discovered in sea cliffs along the
and pitching of the ship. Fortunately, as Fitzroy sailed coast of northern Patagonia. These were described by
backandforthupanddowntheeastcoastofSouthAmer- Richard Owen (1804–1892), the great 19th century anat-
ica, Darwin literally spent two-thirds of his time on land omist and paleontologist who in 1842 gave dinosaurs
making geological observations and collecting all manner their name. Actually, Darwin had a near miss on dino-
of specimens, including plants,animals, rocks, and fossils. saurs. Drexel University paleontologist Ken Lacovara is
He shipped crate after crate of specimens back to Eng- today excavating a rich dinosaur site today in southern
land,avaluablelegacy indeed.Hebecameagreatdisciple Patagonia located about a day’s hike from the spot
of geologist Charles Lyell, whose Principles of Geology where Darwin and a small party from the Beagle turned
back from their attempt to march from Atlantic to
(published in three volumes between 1830 and 1833) pro-
Pacific across the rugged Andes (Dodson, 2009). Had
vided an indispensible resource for interpreting what he
Darwin persisted 1 more day, he might be remembered
observedinSouthAmerica.Hewasenthralledbyvolcanic
in history as a great dinosaur paleontologist. As it was
landscapes, coral atolls, and evidence of tectonic uplift by
he never found a single dinosaur fossil, and he is hon-
which vast areas of Patagonia were raised out of the sea
ored in only a single dinosaur name, Aniksosaurus dar-
inrelativelyrecentgeologicaltimes.Themoreevidencehe
wini (Mart´ınez and Novas, 2006). Dinosaurs played no
saw for the antiquity of the earth, the more he doubted
role in Darwin’s arguments. Dinosaur paleontology was
the historical reliability of the Biblical creation account.
then in its infancy. The first dinosaur, Megalosaurus,
Returning at last to England in October 1836, he
was named in 1824, and by 1859, barely a dozen had
parceled out biological and paleontological specimens to
beendescribed.
various experts for description but reserved the geological
Fast forward to today, well over a thousand dinosaur
material for himself. Recognizing his owndeficienciesas a
names have been proposed, although a significant num-
biologist, Darwin selected one group of organisms to
ber of these are technically invalid for a variety of rea-
describeanddevelopexpertise.Initiallyin1846,hisinten-
sons, including inadequacy of type fossils, junior
tion was to describe a new genus and species of barnacle
synonymy, or preoccupation (Dodson, 1990; Benton,
thathehadrecognized,butasheimmersedhimselfinan-
2008). The number of dinosaurs that can survive critical
atomical minutiae and taxonomic analysis, he became scrutiny at the time of this writing is roughly 620 gen-
utterly enthralled. He ceased his labors only 8 years later era. This number has swollen by more than 90 since
when he had monographed the entire crustacean infra- 2006, when Wang and Dodson (2006) reported the count
class Cirripedia both living and fossil. He emerged from at 527 genera. In China alone, more than 30 genera of
the exercise a true biologist, not merely a naturalist. He new dinosaurs have been described in 4 years. In 2007,
earned a medal from the Royal Society for his consider- China passed the United States to become the greatest
ablepains. source of dinosaurs on earth. One of the major props of
One of the fruits of his travels was that in examining Darwin’s argument for evolution is that the fossil record
so many plants, animals, and fossils during his travels, is incomplete and that a better understood fossil record
Darwin came to doubt the fixity of species. Although would document evolutionary transitions with greater
evolution was truly in the air at this time, no previous frequency.Althoughcreationistslovetomock thealleged
writer had ever amassed the amount of reliable data incompleteness of the fossil record, (e.g., Gish, 1995), the
that Darwin did to make the case that evolution had growth of the fossil record of dinosaurs, for example,
indeed occurred. In preparing the vast synthesis that is from extremely incomplete to somewhat less so, during
The Origin, Darwin drew on every discipline he could, the past 2 centuries is a matter of record (Dodson, 1990;
including taxonomy, anatomy, physiology, embryology, Wang and Dodson, 2006). The latter authors estimate
biogeography, geology, and paleontology. Moreover, Dar- that only a third of all dinosaur fossils have yet been
win outlined the underlying mechanism, natural selec- recovered. The fossil record has recently offered up sev-
tion, acting on the substrate of natural variability. The eral spectacular transitional fossils, including the Late
Origin sold out instantly following its publication in No- Devonian ‘‘fishapod’’ Tiktaalik rosae intermediate
vember, 1859, and quickly enjoyed a second edition in between panderichthyid sarcopterygian ‘‘fish’’ and basal
January, 1860; the U.S. edition appeared in 1860, and tetrapods (Daeschler et al., 2006) and the Eocene walk-
the book achieved both scientific and popular success. ing whale Ambulocetus (Thewissen et al., 1996). More
Like Galileo before him, Darwin wrote in language ac- such transitional forms may be expected in the future
cessible to lay people as well as to scientists, and his as more and more fossils are found. Prothero (2007)
ideas achieved broad though not universal acceptance in documentsnumerousexamplesoftransitionalfossils.
his lifetime. Only in the 20th century, following the Given the tremendous growth in our knowledge of di-
rediscovery of Gregor Mendel’s experiments with peas in nosaur fossils, it is not surprising that a great intellec-
a monastery garden from 1856 until 1864, did the tual enterprise is devoted to the description and
genetic basis for evolution become known. Today, we are classification of dinosaur fossils, and the reconstruction
grateful heirs of Darwin’s legacy. So, successfully did of their phylogenetic histories. In recent decades, phylo-
Darwin make his case that Dobzhansky (1964, 1973), genetic reconstruction has followed the methodology of
one of the great evolutionary biologists of the 20th cen- phylogenetic systematics (a.k.a. cladistics) expressed in
tury, declared ‘‘Nothing in biology makes sense except in the form of cladograms, which began to appear in dino-
the lightofevolution.’’ saur studies in the mid-1980s (e.g., Milner and Norman,
1242 DODSON
1984; Norman, 1984; Sereno, 1984, 1986; Gauthier, cheeks. The EPB does not support the speculation; it is
1986). Cladograms are now commonplace and have a level III inference. No bird or croc has cheeks. None-
achieved considerable sophistication and maturity (e.g., theless, the unique inset of teeth from jaw margins and
Sereno, 1999). Part of the appeal of cladistics is the outward-sloping occlusal planes in hadrosaurs and cera-
apparent precision that the methodology offers as huge topsids make it a respectable speculation that cheeks
datasets of binary characters are examined. For many if werepresent.Itistheuniqueandunexpectedcharacters
not most paleontologists phylogenetic analysis is the and combinations of characters that make dinosaurs
principal thrust of their scholarship, and great intellec- suchengagingsubjectsofstudy andspeculation.
tual capital may be expended in generating and defend- When I entered the field of dinosaur paleontology in
ing cladograms. Cladistics has brought with it an arcane the late 1960s, it was just emerging from a rather quiet
terminology that can be unsettling to the uninitiated. A period, although the seeds were being laid for a great
clade is defined by apomorphies or derived characters renaissance. In the 1960s, the late John Ostrom of Yale
(evolutionary novelties) and taxa arrayed on a clado- University wasconducting expeditions to Cretaceous fos-
gram may be more derived or may basal. The value- sil beds in Wyoming and Montana. Ostrom’s fossil dis-
laden terms ‘‘primitive’’ and ‘‘advanced’’ are eschewed. coveries, particularly of the immortal raptor
One aspect of cladistics that bears comment for the Deinonychus (Ostrom, 1969) both directly and indirectly
uninitiated is that of holophyly. It is mandated within provided Ostrom with the ammunition to make a con-
the system that monophyletic clades consist of basal vincing case for warm-blooded dinosaurs (Bakker, 1968,
taxa plus all descendents. Because birds are now 1971) and the concept of the dinosaurian ancestry of
regarded as theropod descendants, birds are now consid- birds (Ostrom, 1973, 1974, 1975, 1976). Thomas Henry
ered as dinosaurs (Kentucky fried dinosaur for lunch, Huxley posited dinosaurian ancestry for birds in 1868,
anyone?). If birds are excluded, an artificial paraphyletic but the idea underwent eclipse when Heilmann (1927)
group is created. The clumsy phrase ‘‘non-avian came out in favor of thecodont ancestry. Ostrom was a
dinosaur,’’ designating all dinosaurs not actually birds, fine anatomist (Ostrom, 1961) and functional morpholo-
is sometimes used. This volume primarily discusses gist (1964, 1966, 1974). I am proud to claim John
dinosaurs of the non-bird kind, and I beg the reader’s Ostromasmymentor.
indulgence fornot usingthislinguistic contortion. Dinosaur studies have exploded in recent years. The
Contrasting with historical analysis of phylogenetic total number of dinosaurs known worldwide has roughly
reconstruction is the ahistorical approach of functional quadrupled since 1969. Dinosaur paleontology has
analysis (Weishampel, 1995). Functional studies draw on attracted some of the brightest minds in science, includ-
physical and mechanical properties of biological materi- ing two certified geniuses (John Horner, Paul Sereno).
als anddraw heavilyonanalogieswithliving organisms. In my strictly objective judgment, functional morpholo-
Functional studies bring dry bones to life and hang liv- gists are la cre`me de la cre`me among paleontologists.
ing flesh on them, as did Ezekiel of old, creating a true Many threads in my life have crossed in weaving this
paleobiology. This truly synthetic activity often begins in special issue of Anatomical Record, the first of which
the dissection laboratory, or the physiology or biome- involved reconnecting with my old anatomy tablemate,
chanics lab, and usually involves information from the associate editor of AR Jeffrey Laitman. We were part-
soft anatomy of living animals mapped onto fossils. ners in crime at Yale Medical School in 1973, back when
Whenthetwoapproachesarecombined,atruecompara- we were both intellectual saplings. I vividly remember
tive biology emerges. Witmer (1995) has provided pale- Jeff’s ebullient chatter and wit, which made dead things
ontologists with a valuable tool for inferring soft tissue so much fun! Many years later, we are both established
structures in extinct organisms, the extant phylogenetic in our careers, I as a veterinary gross anatomist and di-
bracket (EPB). The fossil under study is placed in a phy- nosaur paleontologist, Jeff as medical gross anatomist
logenetic context, and the bracket consists of living ani- and professorofotorhinolaryngology.Jeffwasananthro-
mals phylogenetically on either side of the fossil animal pology and anatomy graduate student with a keen inter-
in question. For example, the phylogenetic bracket for a est in the comparative anatomy of the upper respiratory
dinosaur consists of crocodilians and birds. If a soft tis- tract in hominid evolution, with a subsequent digression
sue structure is found at both ends of the bracket, then toward marine mammals. Our paths recently crossed
it is a level I inference (highly likely) that the extinct when young Benjamin Laitman, Jeff’s son, who is a
animal also carried the structure in question. For a level brilliant (and friendly) student at the University of
II inference, the soft structure is found at one end of the Pennsylvania, began working in a neuroanatomy lab
bracket but not at the other end. It may or may not be down the hall from my office. One thing led to another,
present in the fossil; it is less certain. If it is found in and ultimatelythisspecialissuehasappeared.
neither living animal, it is less certain still to have char- Jeff charged me with putting together a high-level col-
acterized the fossil. A level III inference does not repre- lection of papers on functional morphology of dinosaurs.
sent impossibility; it just cannot be regarded as I thought of the people whose work I greatly admire and
anything stronger than a speculation. Four-chambered issued invitations. Of course not all were able to accept,
hearts, for example, are found in both crocodilians and but those who did have produced some quite dazzling
inbirds;theexistenceofafour-chamberedheartindino- work if I may say so. Many of the authors are at early
saurs is a level I inference, a highly respectable specula- stagesoftheircareers.Itishardlysurprisingthatyoung
tion. Crocodilians are ectothermic, birds endothermic. researchers are showing the way and pushing the enve-
We may speculate that dinosaurs are endothermic; they lope. This is as it has always been and should be. If my
may well have been, but evidence must be evaluated students do not run circles around me, then perhaps
verycarefully.Itisnosurething.Evidencehasbeendis- I have not selected wisely. The reader may be extra-
cussed for years whether plant-eating dinosaurs had ordinarily surprised at the depth of the biological
DINOSAURSINTHEYEAROFDARWIN 1243
information that our authors have been able to extract and Ridgley (2009) reconstruct the brain of tyranno-
from these long-dead beasts. With fatherly pride, I have saurs. They confirm enhanced olfactory abilities; infer
to point out that my students and my students’students the capacity for coordinated rapid eye and head move-
are well represented among the authors. My students ment consistentwithactive predation,and notea behav-
include authors Guenther, Schachner, Tanoue, Tumar- ioral emphasis on low-frequency sounds. Orientation of
kin-Deratzian and coauthors, Grandstaff, and You. My the semicircular canals suggests that the skull is ori-
students’students include Farke (via Cathy Forster) and ented slightly below horizontal in Tyrannosaurus, more
Larry Witmer (via David Weishampel); Hieronymus and strongly so in Nanotyrannus. D’Amore (2009) has per-
Holliday are my doctoral great-grandchildren via fellow formed remarkable experiments on feeding Komodo
Witmer. In addition, Chinsamy was my postdoctoral, dragons while a student at Rutgers University. In this
and I served on the thesis committee of D’Amore (and contribution, he takes a safer course of action by deter-
also Witmer). I should also mention two students not mining the role of denticles in the teeth of small thero-
included among the list of authors. Eric Morschhauser pods. He develops a model that relates tooth curvature
and Andrew McDonald are first-year graduate students to angle of penetration of the food substrate and proxim-
who have aided me with editorial chores and I am grate- ity to the jaw hinge. The model explains why the distal
ful to them. I have no genealogical connection with the margin of the tooth is heavily denticulated but the
authors offive papers.Wepaleontologistsare wellaware mesial margin has a ‘‘dead space’’ at the base that is
of intellectual genealogies, and with great pride I can free of denticles. David Evans at the Royal Ontario Mu-
trace mine back to Joseph Leidy (1823–1891), the great seum has teamed up with the Witmer laboratory to ana-
anatomist, paleontologist, and microscopist at the Uni- lyze the brains of lambeosaurine duckbills, the
versity of Pennsylvania (see Laitman, 2009). Leidy is dinosaurs with the elaborate crests on the tops of their
honored as the father of American Paleontology (‘‘Ah heads (Evans et al., 2009). They demonstrate that the
yes!’’ exclaimed Cathy Forster, ‘‘But who was the small size of the olfactory region of the brain is inde-
mother?!’’). It was Leidy who described the first Ameri- pendent of the elaboration of the crests. Overall brain
can dinosaurs and he who first presented evidence for size is large for dinosaurs, comparable to that of highly
an upright dinosaur as he first reconstructed Hadrosau- derived maniraptoran theropods. The elongate cochlea is
rus foulkii from New Jersey, the hadrosaur or duck- consistent with the reception of low-frequency sounds,
billed dinosaur known to science. I am honored to share and the entire assembly suggests social habits in hadro-
in thefertilelegacyofLeidy. saurs. Phil Bell is a student of Eric Snively’s at the Uni-
The diverse collection comprises 17 papers, including versity of Alberta. Bell et al. (2009) compare the forces
seven devoted to anatomy of the skull, four to anatomy on the mandible of hadrosaurids versus ceratopsids.
of the postcranial skeleton, and six using skeletal anat- Hadrosaurids (duck-billed dinosaurs) and ceratopsids
omy to infer aspects of the biology of dinosaurs. Taxo- (horned dinosaurs) are quite distinct clades of dinosaurs
nomically, the coverage encompasses four papers with a that share superficially similar dental batteries. The
focus ontheropods, including Tyrannosaurus, fivepapers authors use CT scans and FEA analysis to determine
dealing with ceratopsians or horned dinosaurs, three the distribution of stress in jaws of each group. They
papers on hadrosaurs, one on ankylosaurs, and one on confirm previously hypothesized mandibular rotation in
pterosaurs, which are not dinosaurs but are certainly hadrosaurids. Ceratopsids generate greater bite forces
Mesozoic archosaurs. Several papers are taxonomically thanhadrosaurids, directedin anorthaldirection.
broad in scope. The perceptive reader will notice that KyoTanoueasa graduate student at the Universityof
sauropods and stegosaurs are conspicuously absent, Pennsylvania had the privilege of working in China on
although not intentionally so. A sauropod paper was the exquisite skulls of diverse newly discovered basal
commissioned but the author was not able to deliver it. horned dinosaurs. Tanoue et al. (2009) determine the
Some of the modern techniques delivered include finite progression of bite forces through basal ceratopsian phy-
element analysis (FEA), CT scanning, and high-resolu- logeny. By applying a model of levers, input forces, and
tionhistologicalsampling. resistance arms to the series, Tanoue et al. are able to
The first section is devoted to cranial anatomy. Even identify morphological changes that result in the
classical descriptive musculoskeletal anatomy becomes improvement oftheceratopsianmasticatorysystem.
spectacular as visualized for us in the phylogenetically Tobin Hieronymus is another product of the Witmer
calibrated reconstructions by Holliday (2009). Holliday, a laboratory. Hieronymus et al. (2009) elegantly tackle
student of the Witmer laboratory, uses unprecedented the interesting problem of determining the functional
phylogenetic rigor and comparative of morphology of significance of the skull of the peculiar hornless horned
extant sauropsid reptiles and birds to reconstruct the dinosaur Pachyrhinosaurus. Pachyrhinosaurus lacks
jaw muscles of dinosaurs, which he does with particular bony horn cores but instead bears a thick bony pad. By
elegance. He plays particular attention to muscles that surveying histological features of rhinoceros, musk
leave skeletal scars and those that fail to leave such oxen, and hornbills, the authors identify key histologi-
scars. Larry Witmer has established an extraordinarily cal features that correlate with osteological features in
productive anatomy lab at Ohio University in Athens. Pachyrhinosaurus. They conclude that this horned di-
He and his students have performed countless dissec- nosaur possessed a thick cornified pad for head-
tions of the heads of extant reptiles, birds, and mam- butting.
mals. They haveinjected arteries, veins, and air sinuses, The second section treats topics on postcranial anat-
and have performed all manner of CT scans. Witmer is omy. Andy Farke is a ceratopsian researcher at the Alf
also expert on the visualization and presentation of Museum in Claremont, CA. Farke and Alicea (2009) CT
three-dimensional data using color and transparency, scan cross sections of the femora of terrestrial birds and
and his work quite defines the state of the art. Witmer non-avian theropods to test whether orientation of the