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Peter Dodson

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Peter Dodson described John Ostrom as his "beloved and highly esteemed mentor."[1] After Ostrom's 2005 death Dodson jests that he had become "the senior citizen of ceratopsian studies."[1] Dodson says his interest in dinosaurs began in the 1950s.[1] Although noting that at the time there was not as much "dinosaur 'stuff'" he describes early encounters with dinosaurs in Disney's Fantasia, the Chicago Field Museum, and books by Colbert and Roy Chapman Andrews.[1] The Fantasia viewing came at the encouragement of his mother, a classical music enthusiast.[1] He described himself as being "enthralled" by the segment detailing the evolution of life to the KT extinction event.[1] Dodson said he does not actually remember seeing the dinosaurs at the Field Museum but does remember seeing mummies and being especially excited about a coal mine exhibit in the Museum of Science and Industry.[1] The books he was provided by his father, who was a professor of evolutionary biology.[1] Dodson says these early experiences were "important" and says that he feels "privelege[d]" when children visit his lab or he has an opportunity to speak at elementary schools.[1] Dodson recalls corresponding with "a bright young fifth-grader from rural New York State" named Matt Lamanna who he later met when Lamanna started college.[1] Dodson later supervised Lamanna's PhD and "now enjoy[s Lamanna's] collegiality at the Carnegie Museum."[1] Dodson says that Lamanna is "living proof for the need to take children seriously[.]"[1]

The Dodson family moved to Aylmer, Quebec when he was eleven years old.[1] There he attended the University of Ottowa, where his father taught while living at home.[1] He described his circumstances as allowing him to "[enjoy] the benefits of home cooking and free tuition."[1] Dodson graduated in 1968 and became a graduate student at the University of Alberta.[1] He considers this transition to be his formal entry into the field of paleontology.[1] Dodson reflected that his professional career has spanned over five decades and expressed hope for a sixth.[1] Acquaintances made during his career include significant figures from the end of the 19th century and beyond including scientists like Alfred Sherwood Romer, George Gaylord Simpson, Edwin H. Colbert and E. C. Olson who were still attending Society of Vertebrate Paleontology meetings in 1967 when Dodson himself began attendance.[1] He described these figures as "historical greats," but considers Charles M. Sternberg to be the paleontologist whose acquantance gave him the most pride.[1] Sternberg made weekly visits to the paleontology labs at the National Museum of Canada.[1] Dodson worked in the prep lab under Dale Russel, who Dodson described as his "ever-ebullient mentor".[1] Dodson regrets not having taken a photograph of Sternberg, a lapse in judgement he attributed to a "deficient" sense of history which was only rectified after "gain[ing] a proper sense of awe at the human dimension of discovery and scholarship" as he matured.[2] "Dodson coined the term "ceratophile," meaning "lover of horns" to refer to paleontologists interested in the study of ceratopsian dinosaurs.[3]

Dodson regards himself as part of a historical continuum of scientists, preceded by his academic mentors Dale Russel, Richard C. Fox and John Ostrom.[3] He called them his "[d]ads[.]" Dodson traces his academic "lineage" back through John Ostrom all the way back to Joseph Leidy, the "father of American paleontology."[3] Since Leidy was Edward Drinker Cope's mentor and Yale and Philedelphia were connected to OC Marsh, Dodson sees his academic heritage as an "interesting blending" of the legacies left by both sides of the Bone Wars.[3]

Dodson described his entrance to the field of ceratopsian research as unintended. He described the field as "quiet" when he began researching, but the fifteen years preceding 2010 had been "very active."[3] Dodson was a geology major at the University of Ottawa and while paleontology formed part of the curriculum he seriously considered doing graduate work in sedimentology and geomorphology which were also found interesting.[3] In 1965 and 1966 Dodson, accompanied by David Dineley, participated in his first paleotological field work on Somerset island, located in arctic latitudes in Canada.[3] They collected Silurian "shelly invertebrates" and Devonian ostracoderms and placoderms.[3] In 1967 Dodson worked for the National Museum of Canada's paleontology during what he called a "magical summer."[3] This was the same laboratory that Lawrence Lambe used while doing research that first brought attention to Canadian dinosaurs at the beginning of the 20th century.[3] While working there Dodson encountered C. M. Sternberg and Wann Langston Jr. Langston spent a month in the lab while Dodson was there while studying the dinosaur Pachyrhinosaurus canadensis.[3] Dodson befriended and came under the tutelage of paleontologist Dale Russel while at the museum's paleo lab.[3] Dodson stayed in Canada while doing his master's degree in order to avoid the Vietnam War, even though his first plan was to study under Langston in Texas.[3]

Dodson was accepted to the University of Alberta where he studied under Richard C. Fox, a path suggested to him by Russel.[3] While studying under Fox, Dodson recalls receiving research advice from Russel.[3] During the summer of 1968 in paleontology, Dodson did ten weeks field work in Dinosaur Provincial Park to collect data for his master's degree.[3] He was accompanied on this expedition by his new wife, Dawn, who was a field assistant. Although his time in the field was spent studying the taphonomy of a ceratopsian bone bed, he still wasn't pursuing them as a specialty.[3]

Dodson transferred to Yale to pursue his PhD. At the time, Yale was the only location in the United States where dinosaur research was being pursued "vigor[ously]."[3] This was during what Dodson termed a "'quiet' phase" in the field, after Colbert of the American Museum of Natural History moved to Flagstaff, Arizona for retirement. Nevertheless, Yale paleontologist John Ostrom continued to shake things up, publishing eye-catching research on hadrosaurs and ceratopsians.[3] When Dodson started at Yale, Ostrom had recently concluded a five-year research program in the Big Horn Basin's Cedar Mountain Formation.[3] This fieldwork resulted in the discovery of an entirely new Early Cretaceous dinosaur fauna, including Deinonychus.[3] Ostrom had also been involved in the rediscovery of the first Archaeopteryx speciemen new to science since 1877.[3]

After arriving at Yale, Dodson encountered Robert T. Bakker, who was starting to promote the idea of warm-blooded dinosaurs.[3] Two years later, Jim Farlow also arrived at Yale.[3] Of these two, Dodson characterized Bakker as a "stimulating friend" and said Farlow "looms large in [his] early ceratopsian studies."[3] Dodson described these as "exciting times[.]"[3] His research focused on the biometrics of dinosaur growth series.[3] At Ostrom's suggestion, Dodson used alligators as a model animal.[3] Although his analytical techniques were "primitive," the study produced useful results that continued to be cited for decades afterward.[3] The same year, Dodson published another biometric study of based data collected by Ernest Lundelius about two species of lizard in the genus Sceloporus.[3] Dodson found that there were real differences between the sexes, but this was "difficult to uncover," and the analysis was "complicated by taxonomy."[3]

After his modern reptile biometric studies, Dodson began related work in dinosaurs.[4] In the easier study, Dodson found evidence for sexual dimorphism in Protoceratops andrewsi by applying statistical methods to study their growth.[4] In the larger specimens there were two distinct morphs, one with an "arch over the nose" where the later ceratopsids would have nose horns, a wider and taller neck frill, and "broadly flaring jugals."[4] The other morph's corresponding features were less thoroughly developed.[4] Dodson concluded that the morph with the larger more spectacular skull features were male and the other morph was female.[4] The "eggshell" thinness of the bone supporting the frill convinces Dodson that the structure existed for display rather than for anchoring muscles as some previous researchers had suggested.[4] This study and its conclusions had historical precedents in the form of a "tentative" suggestion by Brown and Schlaikjer in 1940 and an "analytica[l]" paper by Kurzanov in 1972.[4] Dodson's own work had several advantages over previous research, including the "rigo[r]" of its mathematics, the specimens all originate from a single site (the Flaming Cliffs), as well as the number of specimens involved (Kurzanov only examined seven skulls in his study).[4] Dodson says that Protoceratops has more evidence for sexual dimorphism than any other dinosaur.[4]

Dodson also found evidence for sexual dimorphism in Corythosaurus.[4] This research went unchallenged for 30 years until 2007 when David Evans et al. demonstrated the "putative sexes" to in fact be "time successive species" on the basis of "new stratigraphic evidence from the Dinosaur Park Formation."[4] Dodson admits he was wrong, but expresses confidence that his Protoceratops work won't be similarly debunked.[4]

While working on his dissertation, Dodson was encouraged by Jim Farlow to further investigate ceratopsian sexual dimorphism and social behavior.[5] Farlow suggested Dodson use ungulates as analogues for modeling ceratopsian behavior.[5] Together they published a speculative study concluding that centrosaurines were probably less social animals than chasmosaurines since the former have smaller frills with less display potential and horns not suited for coupling with another males during agonistic behavior.[5] Chasmosaurines had showy frills and paired brow horns they thought would be better suited for complex social behavior.[5] However, Dodson notes that if his and Farlow's ideas were true it would be expected that paleontologists would find bonebeds of chasmosaurines but not centrosaurines.[5] In fact it is almost the opposite case.[5] Although some chasmosaurine bone beds are known, like for Agujaceratops and Triceratops, many more centrosaurine bonebeds are known and from a greater diversity of taxa.[5] Even the chasmosaurine bonebeds that are known are inconsistent with the predictions since it is the short-frilled Triceratops best known from such deposits rather than those with more conspicuous frills.[5] Dodson also chided himself for not catching his mentor Ostrom's mistake of at the time classifying Triceratops as a centrosaurine even though older workers like C. M Sternberg had already recognized it as a chasmosaurine decades ahead of time.[5] Looking back, Dodson dismissed the study as representing "the rashness of youth."[5] After this study Farlow and Dodson "went [their] separate ways."[5]

After completing his dissertation, Dodson turned his attention away from ceratopsians for a decade.[5] He got a position as gross veterinary anatomist at the University of Pennsylvania School of Veterinary Medicine.[5] Dodson was extremely surprised to end up with that position and describes himself as initially being a little "dismay[ed]" at the time.[5] Dodson began researching the Late Jurassic Morrison Formation with Bob Bakker and others, his first project since his time at Yale.[6] Afterwards, he moved on to study Dinosaur Provincial Park in Alberta. Dodson found that 24.7% of dinosaur skeletal remains and 26.4% of Judithian microfossils were the remains of ceratopsians.[6] Hadrosaurs were twice as common.[6]

Dodson described himself as a generalist rather than a specialist within diosaur paleontology at this point in his career.[6] He lacked "in-depth" knowledge of ay particular group of dinosaurs.[6] In October 1981, Dodson received a phone call regarding a partial specimen of a small ceratopsid collected by Eddie and Ava Cole, owners of a Wall, South Dakota fossil shop.[6] Dodson was excited about the find due to the rarity of small dinosaur fossils and the "particular" rarity of small ceratopsid remains.[6] Additionally, the fossils originated from the Judith River Formation of north central Montana, a stratum notable for being "rather stingy in high-quality specimens" compared to other Cretaceous formations in western North America.[6] Dodson collaborated with the Coles to excavate the rest of the skeleton the next year and brought it back to Philedelphia's Natural Academy of Sciences.[6] He named it Avaceratops lammersi after Ava Cole and the owners of the land from which the specimen was excavated.[6] In life the animal would have been 800 mm tall at the hip and 2.3 m log.[6] The skeleton was 70% complete, and lacked preserved horns, so reconstructions of the horns are by nature speculation.[6]

Dodson expressed frustration due to some scientists' relutance to include Avaceratops in their phylogenetic analyses.[7] He argued that although juvenile specimens are often more difficult to have their phylogenetic position determined,that this is no excuse for excluding them from analysis.[7] He noted that Australopithecus is based on the Taung child whose life age was estimated at being three years, but neverthelesshas proved useful in understanding human evolution.[7] The primary factor hindering phylogenetic investigation of Avaceratops is the lack of adult horns and frills.[7] In cladistic analyses juvenile animals tend to turn up as more basal forms than their species really is.[7] Dodson remarked that this may be a weakness with cladistics itself.[7]

Dodson describes the discovery of Avaceratops as a turning point in his career, which committed him fully "both scientifically and emotionally, to ceratopsians".[7] David Weishampel was praised by his mentor Peter Dodson as "the kind of student one can get used to."[7] Weshampel graduated with his PhD in 1981.[7] He then moved on to do postdoctoral work in Tubingen as part of a NATO fellowship. In 1983, Weishampel began working at Florida International University.[7] The next year, Weishampel began working on The Dinosauria, enlisting Peter Dodson's help for the chapter on neoceratopsians.[7] Dodson wrote the chapter during a 1985 to 1986 sabbatical.[7] To make the book authoritative down to the species level, Dodson tried to make sense of the many Centrosaurus species named over the years.[8] He used similar techniques to his past work on Protoceratops and Corythosaurus.[8] Although the utility of his bivariate plots were compromised by the lack of juvenile skulls that could be included in the analysis, Dodson did find clusters within Centrosaurus.[8] The type species C. apertus contained two apparent forms, one gracile and another more robust form once regarded as the separate species C. flexus.[8] Dodson concluded that the more robust form was the male and the ore gracile form was female.[8] Dodson also observed that Centrosaurus nasicornus had a tall straight horn on the nose, like in Styracosaurus albertensis.[8] Both forms were also rare.[8] Dodson speculated that Centrosaurus nasicornus might have been a female of the same species as S. albertensis.[8] Dodson also looked for sexes in the genus Monoclonius.[8] Dodson found that this line of research generated little support among other scientists. Sampson and others in 1997 criticized Dodson's inferred connection between Styracosaurus albertensis and Centrosaurus nasicornus.[8] Dodson has said that today he wouldn't try to defend his conclusions and that many Centrosaurus species are regarded as invalid anyway.[8]

In 1993 Dodson published a resistant-fit theta-rho analysis of ceratopsian skulls.[8] He describes this pieces as his "most important rarely cited paper". He says the method of analysis he use is useful for uncovering information on evolutionary paths without the assumption of polar character states that cladistics carries as "baggage".[8] Resistant-fit theta-rho analysis enabled Dodson to check whether ceratopsian classification was "unduly" influenced by traits like frills and horns.[9] By analyzing with or without cosideration of horns or frills or various other traits Dodso found that similar evolutioary trees were being uncovered no matter what traits were removed from the analysis.[10] This implies that eve with ofte incomplete remains ceratopsian classification corresponded well with their evolution and was not excessively iased y superficial cosmetic traits.[10] Dodson said this finding was "most encouraging".[10] Dodson describes his "generation" of paleontologists as being reluctant to embrace cladistics, although his own students were not so hesitant.[10] Paleoartist Wayne Barlow suggested that Dodson write a book on ceratopsians.[10] A 1994 sabbatical gave him the chance to do so, an opportunity he called "much-appreciated" and "a writer's dream."[10] Barlow's wife served as the projects literary agent.[10] The book's publication was disrupted when its editor moved to a new publishing company.[10] After the editor's departure the publisher rejected the idea of publishing the book. Dodson approached his former editor at his new position and 1996 The Horned Dinosaurs was published by the new company.[10] The book included illustrations by both Barlow and Robert Walters, the first artist to depict Dodson's Avaceratops.[10] While writing The Horned Dinosaurs, Dodson examined the question of ceratopsian limb posture.[10] The subject was controversial, with some researchers, like Robert Bakker and Gregory S. Paul supporting fully erect forelimbs while Dodson and many of the worker's who've prepared ceratopsian mounts for museums advocating for a semi-erect posture.[10] Dodson calls the fully erect hypothesis "aesthetically superior" but disputes its compatibility with ceratopsian shoulder and humerus anatomy.[10] Dodson observed that Bakker and Paul lacked experience in mounting ceratopsian skeletons themselves.[10] Dodson saw The Horned Dinosaurs as a "swan song" making the end of his involvement in ceratopsian research since hadn't participated in related fieldwork since 1988 and was busy with two book projects.[10] In 1995, Dodson met Hai-Lu You, a Chinese master's student at a conference.[11] Dodson was "so impressed" that he invited him to be his student at the University of Pennsylvania.[12] In a collaborative 1997 study with Jim Farlow, Dodson argued for the semi-erect posture and criticized the use of ceratopsian tracks as evidence for the erect posture.[12] In 2000 Dodson published a "deliberately polemical" piece critical of cladistics although he "recognize[s] its value."[12] In 2003 Dodson's student Hai-Lu named the basal ceratopsian Magnirostris dodsoni after him.[12] In 2005 Dodson's wife Dawn was honored with another new genus of basal ceratopsian; Auroraceratops, described by Dodson and several Chinese scientists while doing research in Gansu.[12]

Dodson described himself as tending to be "dismissive of the idea of multiple species of Psittacosaurus" on "a priori phiosophical grounds".[12] No new ceratopsian genera were discovered between 1950 when Pachyrhinosaurus was named and 1986 when Avaceratops was named.[13] Dodson is impressed at how revitalized ceratopsian paleontology is, noting that the field once seemed "tired and dated" and attracting little attention from researchers.[13] He describes the "renewed interest" and "new material" as representing an "explosion" of new research.[13]

Quotes:

"Alligators are to paleontologists what Drosophila is to geneticists or Caenorhabditis elegans is to developmental biologists."

"Claims of sexual dimorphism in dinosaurs are properly greeted with skepticism."

"No study in science, and least of all in paleontology, is definitive, in the sense of constituting the final word on a subject."

Ceratopsian specialist Peter Dodson who did his dissertation under Ostrom said he "did not encourage" "wild speculation."

"Perversely, my first horned diosaur lacked horns..."

"Students are the best things that have ever happened in my professional life."

"I see nothing but opportunity for years to come, spiced by new finds at every taxonomic level. The harvest is great but the workers are few!"

Footnotes

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  1. ^ a b c d e f g h i j k l m n o p q r s t u v Dodson (2010); page 3.
  2. ^ Dodson (2010); pages 3-4.
  3. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae Dodson (2010); page 4.
  4. ^ a b c d e f g h i j k l Dodson (2010); page 5.
  5. ^ a b c d e f g h i j k l m n Dodson (2010); page 6.
  6. ^ a b c d e f g h i j k l Dodson (2010); page 7.
  7. ^ a b c d e f g h i j k l Dodson (2010); page 8.
  8. ^ a b c d e f g h i j k l m Dodson (2010); page 9.
  9. ^ Dodson (2010); pages 9-10.
  10. ^ a b c d e f g h i j k l m n o Dodson (2010); page 10.
  11. ^ Dodson (2010); pages 10-11.
  12. ^ a b c d e f Dodson (2010); page 11.
  13. ^ a b c Dodson (2010); page 12.

References

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  • Dodson, P., 2010, Forty years of Ceratophilia: In: New Perspectives on Horned Dinosaurs. The Royal Tyrrell Museum Ceratopsian Symposium, edited by Ryan, M. J., Chinnery-Allgeier, B. J., and Eberth, D. A., Indiana University Press, Part One, p. 3-17.

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