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Horns, Frills, and Gaps: An Interview With Paleontologist Peter Dodson

Christian loves dinosaurs and especially likes to discuss their existence with like-minded dinosaur enthusiasts.


An Interview With Dr. Peter Dodson

Dr. Peter Dodson is a paleontologist and writer based at the University of Pennsylvania, where he is a professor of paleontology and anatomy. Since the 1970s, he has excavated dinosaurs and other extinct animals around the world–from Alberta and China to Argentina and Egypt–and has described and co-described multiple new animals, including Avaceratops (1986) and Paralititan (2001). Along with David Weishampel and Halszka Osmolska, Dodson co-edited and contributed to both editions of The Dinosauria (1990 and 2004), and is currently working on the second edition of his 1996 book The Horned Dinosaurs.

I met with him recently to learn more about how and when he entered paleontology, what we do (and don’t) know about ceratopsian dinosaurs, and where he’d like to dig next.

What kicked off your interest in paleontology and horned dinosaurs in particular?

Paleontology is just something that gripped me as a kid. I saw Fantasia and the march of extinction set to Stravinsky’s Rite of Spring was terribly gripping. I lived in Indiana and very oddly, the mummies at the Field Museum [in Chicago] grabbed me more than the dinosaurs at the time. But when I was eleven, I told my parents I wanted to be a paleontologist, and amazingly, it happened! There wasn’t nearly as much stuff around to distract me.

Horned dinosaurs were always serendipitous. As a grad student at Yale, I did a study comparing the growth series of alligators, lizards, Protoceratops, and lambeosaurine hadrosaurs, and in 1981, I saw what would be known as Avaceratops among a collection of hadrosaur fossils from Montana. I recognized the animal might be new, and with the help of the Delaware Valley Paleontological Society, we raised $5,000 to obtain the Avaceratops for the Academy of Natural Sciences by selling dinosaur cookies.

The Academy at the time had no dinosaur exhibit other than the Corythosaurus skeleton and the Torosaurus skull and they were surprised by the public interest. So they eventually opened a new dinosaur hall in 1986 — the same year I got to name Avaceratops. That led to the Dinosauria (1990) where I got to write the chapter on ceratopsians with Phil Currie, and The Horned Dinosaurs (1996).

What’s been the biggest surprise in your career as a paleontologist?

How many kinds of dinosaurs there are. When you ask people their favorite dinosaurs, they say Triceratops, T. rex, Brontosaurus, Stegosaurus, and Allosaurus, all of which were named between 1870 and 1910. Not only are they continuing to be described, but they’re being described at an accelerating rate. Only three new kinds of dinosaurs were described in the 1960s. By 1990, it was six per year; by 2006, it was twenty per year; it’s currently forty per year.

Known large ceratopsians as of 2013, by Julius Csotonyi. Avaceratops is number 15, the small blue one just above the second text column.

Known large ceratopsians as of 2013, by Julius Csotonyi. Avaceratops is number 15, the small blue one just above the second text column.

How have advances in technology directly affected your work?

When I was a grad student, we analyzed datasets using computer punch cards. We would slip them into a mainframe computer, which would produce its own results an hour later. The Internet didn’t come along till the nineties and I didn’t get a personal computer till 1998, so communication has been easier since then.

3-D scanners have been particularly valuable lately because I can’t take fossils of Psittacosaurus home from China.

Are there any common misconceptions that people have about horned dinosaurs that you feel need to be corrected?

One of the ideas that has been laid to rest is that they used the frills to anchor their jaw muscles. If they engaged in combat with their horns, they would lacerate those muscles. We now think the frills were used for ritualized display or in a breeding context rather than a combat context.

One concept I’d like to address is that Triceratops was just food for T. rex. An adult bull Triceratops would have been a very powerful and dangerous animal that a T. rex would be unlikely to tackle that often.

I did a study about sexual dimorphism in Protoceratops that for many years was accepted for many years but is now roundly rejected. It was always controversial but it’s also hard to replicate or confirm because the beautiful skulls I studied are now behind glass at the American Museum of Natural History [in New York] and [the people there] don’t like to move them.

Skull cast of Triceratops from the National Museum of Natural History, Washington, DC.

Skull cast of Triceratops from the National Museum of Natural History, Washington, DC.

Torosaurus skull at the Academy of Natural Sciences, Philadelphia.

Torosaurus skull at the Academy of Natural Sciences, Philadelphia.

In 2010, paleontologists Jack Horner and John Scanella stirred up both dinosaur experts and fans by suggesting that Torosaurus fossils actually represented elderly Triceratops rather than a separate genus and species. What are your views about Horner and Scanella’s conclusions?

I’m skeptical about [their findings]. It’s possible it’s true, but the transformations they posit are remarkable: The frill of Triceratops is solid and rather short while Torosaurus has an open and very elongated frill. It just seems that Torosaurus reverses all the trends you’d expect to see in Triceratops. [Horner and Scanella] made a statistical mistake by using auto-correlation with squamosal (side frill) bone length and width in their study, ignoring specimens that are outliers like the Torosaurus skull at the Academy. This is the smallest-known specimen and goes against what their study says.

I don’t like the idea one bit. It’s not super-popular [among other paleontologists].

Map of large ceratopsian diversity around 75 million years ago; artist unknown.

Map of large ceratopsian diversity around 75 million years ago; artist unknown.

Are there any mysteries about horned dinosaurs that you’d like to solve or like to see solved?

I’d like to understand their diversity better. There was a very convincing Protoceratops relative from Hungary called Ajkaceratops and I was really impressed by that. There are also [large horned dinosaurs] known from the Eastern United States, which in the Late Cretaceous Period was separated from the West by an interior seaway that stretched from the Gulf of Mexico to Alaska. We have teeth belonging to them from Alabama, so I’m interested in knowing what kind of ceratopsians were there.

There’s an eleven-million year period — 76 to 65 million years ago — where they’re really well-known, and morphological gap between that period and Zuniceratops [from about 90 million years ago]. I’d love to fill that gap.

Are there any aspects of paleontology or prehistoric life that you think deserve more public attention?

I would say dinosaurs have the privilege of enjoying public attention, but they’re only a small portion of prehistoric life. Ted Daeschler is shining a spotlight on the earliest tetrapods and my colleague Lauren Sallan just did a TED Talk on fish extinctions. Fossil mammals are also very important.

As well as a paleontologist, you’re also a practicing Christian. How do your reconcile your field of study and your religion’s texts?

I don’t look to the Scriptures for guidance in scientific matters.

What is the message of [the Book of] Genesis? It was written 3,000 years ago and expressed truths important to [its authors]. It was an expression of radical monotheism; in the beginning, God created the Sun, the Moon, and the stars, as opposed to the Babylonian account, where each of those was a god. The purpose of Genesis is not to say how God created all those things.

Jesus didn’t come to save blue-green bacteria. He came to save you and me.

How do you respond to people who disregard scientific findings on religious grounds?

I just think they’re putting faith in the wrong place and not seeing what God is trying to tell them. Galileo pointed out that the Bible mentions only one planet (Venus) and only says such truths as are necessary for our salvation; the rest is for us to find.

Also, Saint Augustine said that “we do not praise God with ignorance."

The Bahariya Formation in Egypt, home of mid-Cretaceous dinosaurs such as Spinosaurus, Carcharodontosaurus, and Paralititan.

The Bahariya Formation in Egypt, home of mid-Cretaceous dinosaurs such as Spinosaurus, Carcharodontosaurus, and Paralititan.

Finally, you’ve excavated dinosaurs on four continents. If time, money, or politics weren’t an issue, which countries’ bone beds would you like to explore next?

That’s a nice question. I could see myself working in Chile. It’s a lovely country just next door to Argentina, which is the third richest country on Earth for dinosaurs. They named their first dinosaur there in 2015 (Chilesaurus) and have a new ichthyosaur there as well.

A lot of the North Saharan countries provide tantalizing possibilities as well. Paul Sereno has done great work in Niger. There are definite political issues, though, and some of those places have tough climates — you don’t go to Morocco or Egypt in the summer.

My student Tony Fiorillo does work in Alaska, and a Belgian paleontologist called Pascal Godefroit is working in Eastern Siberia and finding interesting things there as well.

They’re even finding Triassic dinosaurs — Plateosaurus — in Eastern Greenland. Can you imagine?