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The Real Jurassic Park: Joseph Leidy's Heirs Reconstruct the Anatomy of Dinosaurs

2009; Wiley; Volume: 292; Issue: 9 Linguagem: Inglês

10.1002/ar.20993

1932-8494

Jeffrey T. Laitman,

Evolution and Paleontology Studies

Locust Walk at the University of Pennsylvania is amongst the most beautiful college streets in America. As I strolled there a few weeks back with Peter Dodson, the Guest Editor of this Special Issue and one of the great professors of that venerable institution, I could not help but imbibe the energy of the students around us mixed with the sweetness of the late spring air. As I had since we first met at Yale around our Anatomy dissecting table in the fall of 1973, I listened attentively to Peter, enraptured by his energetic wealth of knowledge. As anyone who has taken anatomy knows, you always remember your dissection tablemates, and Peter is indeed memorable. At the time we met, I was a trembling, beginning graduate student and Peter an already wizened warrior finalizing his dissertation. As he showed me how to correctly load the scalpels (and always helped me with the band-aids I would need when I missed) he would wax eloquently about ceratopsian dinosaurs, interpreting fossil remains, and reconstructing phylogenies all interspersed with our more mundane daily chores around the cadaver. He was both a role model and a mentor, and I appreciatively followed along. Now, as then, I followed his lead, and that led to a reddish building just off the Walk known as The Wistar Institute of Anatomy. "Why are we stopping here?" I asked, a little perturbed, an ever-compulsive New Yorker eager to get to our work, the precious trove of manuscripts waiting on us in his lab. "I'd like to see if we can visit Professor Leidy," Peter answered, "it would be most appropriate." "Wow, Joseph Leidy has a descendant now at Penn?" I asked incredulously. "No," he answered, "his brain is here." As it turned out, while the great Professor's brain was indeed in residence, we had not made an "appointment" and so he (it?) could not receive us, we were duly informed by the guardian who came to explain. Although Peter implored that we were his academic "relatives" and I chimed in to suggest he (it?) would be pleased to see us (I should have been quiet as this didn't help; we got a stern and odd look), she was adamant that we would need to make an official request much further in advance. The Professor did not receive "drop in" visitors. Although our pilgrimage was not successful on that day, we are making our plans to return, and will request an appointment appropriately far in advance (just as well, as I'd like to be better dressed than I was to meet The Professor.) But, you may ask, why the visit in the first place, why was the brain of this man preserved, and who was Joseph Leidy, anyway, and what were his ties to anatomy, dinosaurs, or this Special Issue, "Unearthing the Anatomy of Dinosaurs: New insights into their Functional Morphology and Paleobiology" (Dodson, 2009a)? All this needs a little explaining. In our world today, dinosaurs are again kings of the planet, at least in terms of which beasties fascinate the public. Who amongst us did not as a child have a plastic T-Rex or Brontosaurus (I know, I know, it's the wrong name now, but Apatosaurus just won't work for anyone who doesn't live in a museum)? Whenever I work at the American Museum of Natural History here in New York, I have to push through the throngs of school children clamoring to see our assortment of Jurassic meat-eaters and Cretaceous vegetarians with names they gleefully try to pronounce with a combination of amazement and joy. If one looks carefully, one can even see how different personality types radiate to different dinosaurs: the aggressive kids run to Tyrannosaurus; the mischievous ones love Velociraptor; the thoughtful ones ponder the horned dinosaurs; the kids with the pocket-protectors love the odd-looking duck-billed hadrosaurs; the vegetarians, gentle souls, and chubby kids, make a direct path to the brontos (I loved the brontos; indeed, my first time being ejected from the museum was due to climbing on one.) Dinosaurs are part of our 21st century culture, as alive today as when they thumped across the earth millennia ago. It is a little difficult to fathom a world in which dinosaurs were not part of our imagination. They are, however, actually a relatively recent part of our vernacular. Indeed, the "Dinosauria" (meaning "terrible lizards") were only first named as such in 1842 by the great British anatomist and paleontologist Richard Owen (1842). He included in this the few extinct "reptile-like" fossils that had been found previously, notably the Reverend William Buckland's Megalosauraus (arguably, the first "dinosaur" discovered in 1824) and the remains of Iguanodon and Hyaeosaurus, described by Gideon Mantrell in 1825 and 1833 (Buckland, 1824; Mantrell, 1825; see Dodson, 2009b, for discussion). So, with the insight and wisdom of the great anatomist Owen, dinosaurs took their first thunderous steps. A little over a decade later they were "brought to life" in the famous reconstructions by Benjamin Waterhouse Hawkins (under Owen's guidance) at the Crystal Palace exhibition of 1854 in Sydenham, England. One can only imagine the awestruck crowds that viewed these great, towering, mega-lizards of the long-distant past! By the mid 19th century, dinosaurs had thus been hatched, so to speak, but certainly were not the subject of everyday conversation, particularly on this side of the pond. That would start to change in 1856, when our Professor Leidy—the "brain" we went to see—would describe the first American dinosaurs from fossil teeth sent to him from deposits along the Missouri River in present-day Montana. Here is where Leidy enters the story. The material was sent to him, as Joseph Leidy (1823–1891) was arguably the preeminent scientist of the middle part of the 19th century. He was the 19th century version of da Vinci, a man whose scope of expertise was so truly extensive that his recent biographer, Leonard Warren, titled his book, The Last Man who Knew Everything (Warren, 1999). The regal Professor of Anatomy at the University of Pennsylvania (which he would hold for almost 40 years), trained as a physician, with knowledge (and many publications) in fields ranging from gross anatomy, to microscopy, to parasitology, to protozoology, to paleontology. The Professor reigned supreme. Indeed, when the American Association of Anatomists—the parent body of this august journal—was founded in 1888 (as the Association of American Anatomists), Leidy was chosen in absentia as its first president. (Basmajian, 1987; Clemente, 1987). It is what my kids would call a "no brainer;" JL (nice initials) was unquestionably the man. Thus, it was no surprise that if one wanted to know what some interesting old bones were, they would send them to the great Professor. (To answer one of my above questions, it was the custom in the 19th century to preserve the brain of a great "mind," for example, Paul Broca's is similarly honored in the Musee de l'Homme in Paris; when my teenage daughter asked me what I was writing about, and I explained the above, she looked at me, patted me on the head and said, "don't worry Dad, yours is safe.") Although Leidy recognized the teeth he had received as belonging to extinct reptiles of various types, and named them scientifically (Deinodon, Trachodon, Troodon, Palaeoscincus), they were not monumentally important specimens, save for the historical nature of their being the first. A few years later, however, Leidy was brought material unearthed from—of all places—New Jersey (more famous in our time for burying the occasional vertebrate). This was a marvelous, and extensive, collection of cranial and postcranial bones that Leidy anointed as Hadrosaurus—the extraordinary-looking duck-billed dinosaur. He estimated it to be 25-feet long and, based upon its small forelimbs and long hind limbs, reconstructed it in a "kangaroo-like" stance, with semi-upright posture (Leidy, 1858, 1865; Dodson, 2009b). The vertical "dinosaur" of our imagination was thus born and, when it was given life at the Academy of Natural Science in Philadelphia in 1868 in the first museum display of any dinosaur, our image of dinosaurs that ligers to the present began to take shape. As the world of the dinosaurs began to gradually emerge, the American West became the epicenter of extraordinary finds. Interestingly, Leidy's role—so pivotal at the outset (he published about 230 papers on paleontology, Warren, 1999)—changed radically and, largely, by his own choice. This was mostly due to the "tone" that dinosaur paleontology gradually accrued to itself in the 1870s and 1880s—a fiery, combative, and combustible cacophony that was more and more unsuited to the scholarly, genteel, multidimensional, Renaissance man from the City of Brotherly Love. This tone was set in place due to a rivalry between two men—Othniel C. Marsh and Edward Drinker Cope—that was arguably amongst the most angry and vitriolic in the history of science (see Shor, 1974; Hellman, 2007). The seemingly never ending battles between Marsh and Cope increased in intensity during the last quarter of the 19th century as each sought pre-eminence in the burgeoning field of paleontology. Cope was a Pennsylvania product who studied anatomy under Leidy and eventually assumed Leidy's Chair in zoology and comparative anatomy at Penn toward the end of his life; Marsh was a Yale graduate who was blessed with a rich uncle, George Peabody, who largely effectuated his being named as the nation's first Professor of Paleontology at Yale. For most of the latter part of the 19th century, dinosaur studies in the United States revolved around this Yale/Penn axis, with Cope and Marsh gaining near Olympian stature, as Leidy, the great Titan of old, withdrew from the battles. The gentle, sweet-natured, scholarly man of the dissecting lab and microscope, could not, would not, compete with often ill-tempered, tabloid-hungry prima donnas that would pay hefty amounts for every fossil the Wild West gave up. He withdrew from the fray, returning to the scholarly pursuits and teaching he was more comfortable in. Part of the sadness of this tale is that while Leidy largely set the stage for our knowledge of dinosaurs, he and his accomplishments were essentially ignored by the egomaniacal appetites of Cope and Marsh. Indeed, most of the fossils that were named by Leidy were renamed by Cope and Marsh (at one time, there were three names for each species!) In speaking of the above "burial" of the findings and accomplishments of Leidy by Cope and Marsh, the famous early 20th century paleontologist and future President of The American Museum of Natural History, Henry Fairfield Osborn, simply and clearly noted in a presentation honoring Leidy: "I am not quite sure, but I doubt if you will find in the writings of Professor Cope or Professor Marsh a single allusion to the work of Leidy" (Osborne, 1923; also see Warren, 1999 for full discussion). Not only were Cope and Marsh gluttonous carnivores in their quest for bones, they were equally rapacious in devouring the memory of the man who made their work possible. Thus, my focus here on Joseph Leidy, arguably the most important, learned, honored, and least remembered great man of 19th century science, and the person who truly birthed the anatomical study of dinosaurs on this continent. It is fitting that his name be honored, and his story retold, in this Special Issue. Peter Dodson, our Guest Editor, is in many ways a true heir and descendant of the great man: like Leidy, a Penn Professor, anatomist, multidimensional scholar, extraordinary teacher and raconteur, and a gentleman of the old school (put up with me, didn't he?). In this Issue, Dodson has used his own gravitas as a doyen of the field (he is the shepherd of all horned dinosaurs, e.g., Dodson, 1996, as well as a historian and interpreter of the field, e.g., Dodson, 2008, 2009b, c) to pull together a wonderful and varied herd of dinosaur anatomists who have collectively worked together to yield a rich volume of the state-of-the-art knowledge of dinosaur form, function, behavior, and evolution. Within this collection, a number of varying dinosaur groups come under the paleontological scalpel, including, the well-known tyrannosaurs, the duck-billed hadrosaurs (first recognized by Leidy), the horned ceratopsians, herbivorous groups like the club-tailed ankylosaurids, to the current "rock stars" of the dinosaur world, the velociraptors. As varied as the groups are, so too are the regions studied with nooks and crannies from head to clawed toe being examined. For those of you, like me, who are not cognoscenti of dinosaur anatomy, studies deciphering the functional anatomy of an array of horns, claws, specialized teeth, cranial crests, tail clubs, and the like, will remind us to why we radiated to the dinosaur halls in the museums in the first place. These are wonderful and wondrous things to behold! A theme that winds through many of the studies—and will resonate with readers of this journal—is the hypothesis-driven science that drives many of the approaches. Elegant tests abound to explore a range of topics, including: how to reconstruct jaw muscle anatomy, the anatomy underlying sensory organization and behavior, bone strength as it effects posture and locomotion, the use of extant species of birds as experimental models of bone structure in dinosaurs, new methods of bone surface texture as indicators of dinosaur aging, and the use of skeletal markers as an aid in determining respiratory biology and behaviors. Most impressive as well are the range of cutting-edge approaches and techniques that are used to extract information from the otherwise silent bones, such as computational modeling, finite-element analysis, and advanced CT analysis. Lastly, but far from least, while the core of the special issue revolves about deciphering the functional anatomy of dinosaurs, considerable insights on behavior patterns, lifestyles, and population biology permeate many studies. As a graduate student at Yale, I became very familiar with the finds of Marsh (filling every shelf of the Peabody—his uncle George's—Museum there) as well as the work of his hated competitor Cope (a large part of whose collection was sold to the American Museum of Natural History in New York; see Preston, 1986). Like most other young students, they were the names that we were weaned on, the names on the fossils sleeping on every dusty shelf. It was only when I began to dig deeper into the core of the science (after actually listening a bit to Peter and getting more interested in the strange beasts he clamored on about) did I start to find, and then appreciate the work of Leidy. Even as a budding anatomist, I could appreciate the meticulousness of his science, his descriptions, comparative anatomical perspective, and understanding of functional underpinnings, aspects that I at times found wanting in the tomes of Marsh or Cope. While Marsh and Cope, with their paleontologist's flair for the drama of obtaining material and the accompanying public glory that ensued, may have done much to capture the country's fascination with dinosaurs, it was Leidy who set the early bar for the scholarship and science of the anatomical interpretation of dinosaurs. Simply put, where Leidy was all about the science of dinosaurs, for Marsh and Cope it at times took a far second behind the glitz and glamor of recognition and adulation. As demonstrated in this Special Issue, Dodson and his like-minded brethren have clearly taken up the mantle in the search to understand the science behind the world of the dinosaurs; they are the true heirs of Joseph Leidy. Indeed, I think the Professor would be most pleased by the work his offspring have produced, and look forward to bringing a copy as a gift when Peter and I visit him on my next trip to Penn.