Talking with… Evan Saitta

Interview by: J. D. Dixon

This week we spoke with Doctor Evan Saitta, a young palaeontologist with extensive experience in a whole heap of countries. We asked about what led him down the path of palaeo; his research into sexual variation, feathers, and more; his amazing achievements; and his advice for fellow scientists thrust into the public eye.

Evan Saitta in northeast Montana while prospecting the Hell Creek Formation with a Field Museum crew.

Hi Evan, thank you for talking with us this week. Firstly, could you tell us about yourself and what you enjoy doing in your downtime?

“No problem! Glad to chat with you!
I grew up outside of Jacksonville, Florida in the US. North Florida is an interesting place. Like the rest of the state it has some influx from places outside of Florida, but it also has a very ‘southern’ history and culture, being right near the border with Georgia. For example, the Jacksonville southern rock band Lynyrd Skynyrd played for my high school’s 1972 prom. My dad’s side of the family has some deep roots in the area, especially on his maternal side. However, my mom grew up in Long Island, New York and my maternal grandmother is from Peru. To add further confusion, my last name is Sicilian and prior to my strictly paternal lineage settling down south, my great-great-grandfather was even implicated in La Mano Nera (‘The Black Hand’) activities of the Sicilian mafia in New York City during the early 1900’s.
I suppose I tend to like outdoor activities and sports. I would go to the beach most days during the summer to skim board or, more rarely, surf – the waves are not super impressive in my area and I am certainly not a morning person. I still have family in upstate New York too, so I learned to snowboard when I was about 10.
I played baseball (like your rounders) as a kid among a few other sports, but I was mostly only good at running the bases and was a bit of a defensive liability when it came to catching and throwing accuracy. So, when I unsurprisingly got cut from my high school baseball team, I knew I’d join track and field (your athletics). I did better in my new sport, allowing me to continue as a non-recruited ‘walk on’ athlete at Princeton University, where I pole vaulted until my second concussion! After that, I managed to scrape by as essentially a practice squad sprinter. However, science was always my passion instead, and I had sadly lost most of my athletic competitive fire by that time.
Now I mostly try to remain active on distance runs and in the weight room. Other than that, I guess I’m a fan of British ales and Irish stouts, American bourbon and Canadian rye, rock and heavy metal (as a spectator without any musical talent), thriller movies, and what your side of the pond calls American football (again, as a spectator).”

Wow that’s a really fascinating history, so when did you decide you wanted to be a palaeontologist? Why palaeontology at all?

“I can’t actually answer the first question because I don’t remember. I’m pretty sure I’ve been interested in palaeontology my entire life as a fully self-aware, conscious individual. I suppose I just haven’t had any better ideas yet. When I was a kid, I was interested in animals, dinosaurs, nature, and science. I begged my parents to take me to the zoo nearly every weekend, and they cultivated my interests. They had a policy that they would never say no when I asked them to buy a book that I had seen – invariably something about science or nature.
If I had to guess, I might have found my first fossils on the beach when I was six or seven years old. At first it was fossil shark teeth, which are extremely common in my hometown, but I eventually grew a fairly decent collection of isolated bones and teeth of Pleistocene and Holocene animals, including fish, turtles, alligators, horses, tapirs, mammoths, bison, camels, ground sloths, glyptodonts, etc.
Although I did always focus my interest on fossils, I also liked science more broadly, especially biology and geology. One of the interesting things about palaeontology is that it provides so many opportunities to think in an interdisciplinary manner. After all, the complete history of life on Earth is a fairly sizeable topic. There is also a fascination when it comes to the extinct organisms themselves. Some are so strange and impressive it is like being able to study movie monsters that are actually real.
I think the only way I would switch disciplines would be if they found life on Mars. But even then, it would probably be fossil remains, so it would just be Martian palaeontology in that case.”

Your undergraduate thesis focussed on North American stegosaurs. What inspired this project in the first place and what was the experience like?

“I volunteered as a high school student on a dig in Montana that happened to be excavating a ‘graveyard’ of multiple stegosaurs. I went with my dad, although I’m not sure he enjoyed carrying buckets of rocks out of a quarry as much as I did. It was clear to the crew that these stegosaurs were unusual – a rare species called Hesperosaurus mjosi (at the time of my thesis, it was instead called Stegosaurus mjosi). This is a more northern type of North American stegosaur, and the back plates in the quarry were showing extreme variation in their shape. I was therefore prompted into looking at North American stegosaurs more broadly with a particular eye towards how their plates varied across different species and within species.”

Evan excavating his first dinosaur fossil, a small stegosaur rib in central Montana within a bone bed. White labels mark bones, and the end of a large limb bone can be seen behind his head.

“Princeton University, where I studied as an undergraduate, requires a senior thesis. Princeton does not have any vertebrate palaeontologists and even my professors whose research had a component of invertebrate or micro-palaeontology would often refer to themselves more as geologists than palaeontologists. Therefore, I figured that stegosaurs would be a fun topic to do my thesis on since vertebrate palaeontology was not immediately available at Princeton. My advisor, biologist Dr. James Gould, did not have palaeontology experience but he did study sexual selection, and at the time, preliminary readings of published studies on stegosaurs made me suspect that the possibility of the observed plate variation being linked to sex was one worth investigating deeper.
It was a great experience and kickstarted my research career. Princeton professors and administrators were extremely supportive of my interests and efforts, including people beyond Gould, such as Dr. Adam Maloof and Dr. Gerta Keller. I think I got to travel to 14 different repositories in the US and Switzerland thanks to Princeton’s financial support. I’m pretty sure I examined nearly every accessible North American stegosaur specimen, at least at the time. I was able to not only measure and photograph fossils, but also perform CT scans and destructively sample fossils to have thin-section slides produced to study the bone tissue with a microscope.”

As you mention, your project was based around sexual dimorphism regarding Hesperosaurus mjosi. Are there any further species or groups you’ve looked at for sexual dimorphism?

“It does indeed seem that Hesperosaurus plate variation was influenced by the sexes of the individuals, because we have lines of evidence against other drivers of variation being sole explanations, such as growth/development or ‘hidden’ species. In fact, a statistical analysis published in January by Dr. Ryosuke Motani also supported sexual dimorphism as an explanation.
I have since published a big paper where we argue that many dinosaurs were likely sexually dimorphic based on evidence from fossils and modern species, but that our statistical methods need to be updated to properly quantify dimorphism. In line with what is known as the ‘replication crisis’ in science, we decided to abandon statistical significance testing in favour of ‘effect size statistics’. We tested our approach with data simulated on the computer and found that in many cases it is possible to calculate a fairly accurate estimate for the magnitude of sexual variation, especially if one does so in a comparative manner across species.
We then estimated that sexual variation in the body mass of Maiasaura (calculated to be a ~ 47% difference between the sexes) was higher and better constrained (i.e., had smaller error bars) than our current estimates for both Psittacosaurus and Tyrannosaurus – likely due to limited data in the latter two dinosaurs.
I further wrote that variation in horn curvature seen in ceratopsian dinosaurs like Triceratops and Centrosaurus, while influenced by development, was also consistent with sexual variation in the horns of modern bovids. Also mentioned as a possible place to find sexual dimorphism were sail-backed dinosaurs like Spinosaurus, since their sails are similar to ornamental structures in some lizards. The list goes on and on for structures that one might suspect to be under sexual selection based on modern animals and therefore dimorphic to some degree: hadrosaur head casques, midline skin spines on the backs of hadrosaurs or sauropods, pachycephalosaur head domes, spur-like claws in Iguanodon, tusks in heterodontosaurs, feathers and bristles in various dinosaurs, coloration patterns, etc.”

Your undergrad thesis and your studies of feathers have attracted quite a lot of media attention, so how did you find being thrust into the palaeontological limelight?

“I’m always happy to talk about science with people, as we are doing here, and it’s of course encouraging when others find my research of interest. I won’t sugarcoat it for you though. Even as a student, when the collective focus has shifted onto me, there have been times that I have unfortunately witnessed certain journalists and academic colleagues far more senior or established than I act in extremely childish and dishonourable ways. Young scientists ought to realize that there are certain topics in palaeontology that are lightning rods for bullying by certain cliques. It can be quite shocking and, for some of my peers, psychologically damaging. Any young researchers reading this should know that they can always reach out to me for support and advice if they are the targets of mobbing.
To move beyond that dismal topic, we can talk about the role of outreach in palaeontology. I am a massive supporter of funding general research regardless of whether there are immediate or obvious practical benefits. The greatest conceptual and technological breakthroughs are often unpredictable or the result of cross-disciplinary synthesis. However, I understand that many might view palaeontology today as a somewhat fringe topic. While the fossil record provided a major foundation for the development of evolutionary theory, which in turn underlies all of biology and therefore medicine, I recognize that many might view research on topics such as virology or oncology as a more immediate return on investment.
Therefore, one of the most direct benefits palaeontology can play in society is in terms of scientific outreach and acting as a flagship to generate interest in science more broadly. Palaeontology, especially in relation to dinosaurs, definitely punches above its weight in terms of media interest relative to the size of its research community. I remember seeing a popular science magazine a few years ago that did a ‘top 100 science stories of the year’, and maybe something like 20% or so were palaeontology related. However, if I had to guess, the number of academic palaeontologists (even including students) is probably only a few thousand globally, and many universities don’t have palaeontologists on staff. Both palaeontology and astronomy play crucial roles for inspiring people to join the scientific pursuit and expose themselves to the scientific method of truth seeking.”

Continuing with your studies, you’ve attended both US and UK universities, but how would you compare the two experiences?

“Something I enjoyed about UK universities was that, because the sports were all club level rather than organized by a governing body (e.g., the NCAA here) enforcing a limited timeframe of participation, I was able to participate as a graduate student (i.e., postgrad) on the Cross Country and Snowsports teams and make great mates through that. Watching rugby was fun too. Go Bristol! Beat UWE!
Perhaps I am biased, but I think the US undergraduate system is often more beneficial since it is a year longer and also forces more courses to be taken outside of one’s speciality (i.e., the liberal arts model of education). I found that many UK undergrads were extremely advanced in their subject but were perhaps too specialized early on, starting from their A levels prior to university (See? I remember things!). I think an undergraduate degree should be slightly more generalized, even if one’s interest is already locked on a particular branch of science.
Unsurprisingly, I do like the UK graduate school model. There are only so many courses you can take at a university before you reach a limit and need to participate in active research yourself. The UK Ph.D. urges people to publish (or at least write thesis chapters) as soon as possible and in rapid succession – something that is typical of an academic position in general. My sense is that some US Ph.D. programs can provide a cushion of many years without as strong of an incentive to publish, which is fine and will benefit some types of people. But again, eventually you have to start participating in the scientific pursuit.
I was lucky to have some great influences during my graduate degree such as Prof. Mike Benton, Prof. Davide Pisani, and especially my advisor Dr. Jakob Vinther. Vinther’s insight that colour patterns in fossils were due to molecular preservation of melanin pigment was so amazing to me that it almost singlehandedly led me to the UK in the first place, which is saying something considering that Benton might be one of, if not the, most published, palaeontologists ever. We had always assumed that we would never know the colour of dinosaurs in life, but now we can reconstruct colour patterns and hues with direct empirical evidence!”

Your post-doctoral work included examining trace metals in exceptionally preserved fossils. It sounds difficult, so what did this involve, and what was your goal with this research?

“We examined a variety of exceptionally preserved fossils, such as vertebrates, plants, and insects, from several fossil localities around the world spanning a broad swath of geologic time. The analysis was done with some colleagues at Argonne National Laboratory in Illinois and my post-doc advisor Dr. Peter Makovicky at the Field Museum of Natural History in Chicago. Specifically, we used X-ray fluorescence on a synchrotron light source to determine the elemental composition of the fossils. A synchrotron is a large, powerful particle accelerator.
We are interested to see if the trace metals present in the fossils correlate with the type of fossil and are biologically derived from the original organism or if they correlate with the fossil’s source and are instead influenced by fossilization. Initial, unpublished results show very similar trace metals across a variety of organisms, suggesting that many of these metals bind to the preserved organic material of the fossils during decay and fossilization. This means that original biological patterns of trace metals in these fossils may be swamped by patterns deriving from fossilization.”

Fossil leaves mounted for XRF elemental scanning in the Advanced Photon Source at Argonne National Laboratory.

That sounds very impressive, we can’t wait to see the publication. So, what would you say have been some of your proudest academic or palaeo moments?

“I’ve had some really thrilling moments in my research. These include:
– Excavating my first dinosaur bone in Montana – a stegosaur rib.
– Getting the chance to scale the fossil-studded cliff face of Dinosaur National Monument, Utah for my undergraduate thesis research (thanks to Dr. Dan Chure) while even using sauropod limb bones to stabilize myself.
– Examining the preserved skin of my favourite fossil (the Seckenberg specimen of Psittacosaurus in Frankfurt, Germany) using laser fluoresce imaging with my collaborators Dr. Michael Pittman and Thomas Kaye.”

An image of the Senckenberg Psittacosaurus produced using laser stimulated fluorescence to study its skin and tail bristles. The light captured by the camera is not the light reflected off of the fossil. Instead, a powerful laser is used to induce fluorescence of the compounds composing the fossil. The laser’s light is removed from the image using a lens filter that blocks its specific wavelength. The skin and bristles are phosphatized and fluoresce yellowish, while the carbonaceous melanin pigment does not fluoresce and appears black. The blue is the resin used to hold the different slabs of rock together.

“- Consulting on artwork by Rebecca Gelernter of the primitive, shaggy plumage on the feathered dinosaur Anchiornis, which even appeared in the New York Times.
– Witnessing my collaborator Prof. Kirsty Penkman’s excitement upon seeing the printout from the liquid chromatograph in York that detected ancient amino acids in a titanosaur eggshell, which I think are the best supported minimally altered proteinaceous components from a dinosaur (see our 2020 bioRxiv preprint).
– Developing a novel ‘pressure cooker’ with Kaye that can artificially mature modern tissue samples within sediment into ‘synthetic fossils’ that are macroscopically, microscopically, and chemically comparable to actual fossils and excitedly splitting open the earliest samples we ran on the equipment as if they were childhood birthday presents.
– Discovering 46 new types of microbes living inside buried dinosaur bone that I aseptically excavated from Dinosaur Provincial Park in Canada alongside many collaborators, but especially Dr. Renxing Liang and the rest of the Dr. Tullis Onstott lab at Princeton (Onstott was actually one of my undergraduate professors).”

Congratulations on so many spectacular achievements. Now, your website details many excursions and trips all over the world, but what has been your best fieldwork experience?

“I’ve been lucky enough to find fossils in North America, South America, and Europe. While the fossil richness of Dinosaur Provincial Park I witnessed alongside my collaborator Dr. Caleb Brown was unbelievable, the most exciting trip was to the Patagonian Desert of Argentina.”

Evan Saitta and Dr. Sebastián Apesteguía in Argentina.

“Any time I get to dig with Makovicky and Akiko Shinya (Field Museum chief preparator) is a good trip, but for Argentina, Makovicky’s crew met up with crews led by Dr. Sebastián Apesteguía and Dr. Guillermo Rougier. Not only did I get to experience South America for the first time, which was fun considering my grandmother’s Peruvian origin, but the mixed group allowed me to get to know many South Americans and learn about their culture. I even got to ‘pratica mi español’ when the camp split for several days and I was the sole Chicagoan who joined the South American crew. My Spanish was extremely bad and mostly forgotten… I did, however, pick up an unhealthy habit for yerba mate hot tea. Near the end of the expedition, I managed to find a nice scapula from a fairly large carnivorous dinosaur similar to something called Skorpiovenator. It was the first big carnivore I have found, so that was a cool personal first.”

A scapula and coracoid from the shoulder of a carnivorous abelisaur found in Patagonia.

Likewise, which museum collections were particularly amazing to visit?

“Obviously, I will say the Field Museum where I did my post-doc. In addition to that, I always enjoy visiting the American Museum of Natural History in New York City for research or even just for pleasure. The Sauriermuseum in Aathal, Switzerland is a private museum built from scratch by the non-academic Hans-Jakob “Kirby” Siber that has amassed one of the most impressive collection of Jurassic dinosaurs from the US, which will ultimately be donated to the University of Zurich. Palaeontology is dependent upon the hard work of ‘citizen scientists’ outside of academia.
My favourite museum from an aesthetic perspective is the Galerie de Paléontologie et d’Anatomie comparée in Paris. It has a Victorian Era style of architecture (I think the French equivalent of that period is termed La Belle Époque) and a ‘cabinet of curiosity’ type of display that looks as if it hasn’t changed much since its inauguration the 1890s. Hundreds of skeletons are mounted in rows as if they were marching, often with minimal information displayed beyond the Latin and French name of the animal on a small label. It is certainly a style you will not typically see in modern exhibits. Perhaps it is not the best educational approach, but it is absolutely my favourite exhibit.”

Modern skeletons in the exhibit hall of the Galerie de Paléontologie et d’Anatomie comparée in Paris.

Do you have any helpful tips or wise words for people who want to become palaeontologists?

“Prior to university, read a lot and do well in school. Reach out to any local museums or universities to look for volunteering opportunities. Look for any fossil hunting guidebooks for the area where you live and go searching for yourself, while respecting local collecting laws and land ownership.
As an undergraduate at university, get as broad of a training in STEM fields as possible. Even getting some basic statistics, coding, physics, or chemistry training will provide you with a unique skill set and a leg up in a discipline that usually draws upon straight geology or biology backgrounds.
Finally, once you are at the stage of doing independent research, I would recommend reading An Instinct for Truth: Curiosity and the Moral Character of Science by Robert T. Pennock and Science Fictions: Exposing Fraud, Bias, Negligence and Hype in Science by Stuart J. Ritchie. The former surveyed over a thousand top scientists and identified the underlying virtues that drive them, while the latter covers ways in which even top academics can fall short of those ideals. Most students are taught the basic mechanics of the scientific method, but I have found these books to discuss far more fundamental values that influence the quality of science such as openness, objectivity, meticulousness, attentiveness, etc.”

Finally, our staple last question, what’s a weird palaeo fact you think people should know?

“The most practical answer to this question would probably have to be about the difficulty humans have in comprehending ‘deep time’ and other topics that deal with differences across orders of magnitude, such as just how rich the richest people in the world are. Many people who struggle in wrapping their heads around Earth history and evolution probably don’t fully appreciate just how long a time four and half billion years is since the formation of the Earth or how long a time nearly 14 billion years is since the Big Bang.
There is something I like to think about while out on expeditions, although the dinosaurs I dig up are admittedly a bit on the older side for the phenomenon that I will describe here to have full effect with the naked eye. While excavating a fossil during a day on an expedition, you expose the bone from the rock and are the first living creature to see that organism in thousands or millions of years. However, the night provides an awesome complement. We often look for fossils in very remote places with little light pollution and, therefore, incredible views of the night sky. It is amazing to think that the light from some of those distant stars you are looking up at from around the campfire was produced thousands or (especially if you have the aid of a telescope) millions of years ago and that some of the light might have been produced around the same time as the ancient organism you were just excavating that day. Due to the vast distances observable in that night sky, you are literally seeing into the past, which is only preserved as ancient remnants on the planet you find yourself sitting. It is humbling to go from such an intimate experience during the day to one so distant that night.”

A massive thank you to Evan for sharing his tremendous tales with us this week, it has been thrilling to learn so much about so many experiences. For more information about Evan, or to find out how to contact him directly, check out his website, Instagram, or LinkedIn.