Serendipaceratops, Again

It's been a week since I last wrote about Serendipaceratops, a glaring problem I'll now correct. A refresher: Serendipaceratops arthurcclarkei is a dinosaur named by Australian paleontologists Mark Rich and Patricia Vickers-Rich based on a single ulna. After seeing a Leptoceratops ulna shown to them by Canadian paleontologist Dale Russell, they decided it represented a neoceratopsian - living tens of millions of years before the other neoceratopsians and really far away from the family's predominant territory of Asia.

As luck would have it, on May 22, 2010, Argentinian Museum of Natural Sciences paleontologists Federico L. Agnolin, Martin D. Ezcurra and Diego F. Pais, joined by Steven W. Salisbury of the University of Queensland, published a sweeping reappraisal of the Mesozoic fauna of Australia and New Zealand. Huge thanks to commenter Jay, who tipped me off to this. I have been able to get a copy of the paper and took a look at it. It's been the subject of debate surrounding nomina dubia, "dubious names." Basically, it works like this: Paleontologist A describes a fossil and decides that it's unique and thus warrants the naming of a new species. Then, paleontologists B through K look at the specimen and decide that the fossil isn't actually that unique, or more associated fossils are needed to make the determination. Paleontologist A's name for the fossil is then considered a nomen dubium. Mickey Mortimer's Theropod Database Blog and Jamie Headdon's The Bite Stuff each have posts discussing their respective opinions on the topic.

As Jay said in his comment, Agnolin et al suggest that Serendipaceratops is probably not a ceratopsian, and cannot be confidently assigned beyond being an indeterminate Genasaurian. The clade Genasauria is a large group that includes the ceratopsians, the ornithopods (Iguanodon, the duck-bills, and their kin), the stegosaurs, and armored dinosaurs like Ankylosaurus and Edmontonia. Almost all ornithischian dinosaurs, except for a handful of the most primitive ones, fall under its umbrella.


The Australian ankylosaur Minmi, by Mariana Ruiz, via Wikimedia Commons.

The authors argue that Serendipaceratops simply doesn't have adequate fossil evidence to draw any strong conclusions as to what kind of critter it was, though they do note that "...the proportions of the ulna of Serendipaceratops are closer to Minmi sp. and other ankylosaurians than to any neoceratopsian." Thus, they decide that Serendipaceratops arthurcclarkei is a nomen dubium.

In the chance that Agnolin and his crew's ideas are borne out, it may be a good idea to horde some Serendipaceratops keychains.

Further Musings on Serendipaceratops

One of the scientists in the media I've come to trust and respect is Steven Novella, the neurologist who co-founded the New England Skeptical Society, hosts The Skeptic's Guide to the Universe podcast, and blogs prolifically. In addition to being knowledgeable in a wide variety of scientific fields, he has that rare ability to clearly articulate the workings of science. A sentiment I've heard him express a few times on the SGU is that contrary to science-deniers' claims of a conspiracy to preserve the status quo, scientists relish when a hypothesis is proven wrong. Or when a provisionally accepted fact is upended. These occurrences create questions. And questions are what fuel science. Like most people, I have little contact with scientists in my daily life. I'd like to think that Dr. Novella's observation is mostly true of scientists in general. He's extremely wary of casually making weak generalizations, but I'd love to hear about the experiences of other people.

This isn't to say that I expect superhuman levels of objectivity and logic of scientists. Everyone has flaws in their thinking. But scientists - at least those who have paid their academic dues - are trained to recognize those flaws so they don't influence the work. What I expect of scientists (and hope of anyone) is healthy skepticism, especially of their own conclusions and biases. This is a basic requirement, really. I try to hold myself to the same standard.

What does this have to do with Serendipaceratops? Paleontology has always been my favorite scientific pursuit to learn about, and part of that is because it's such a rich mental playground, pulling in so many other sciences. Serendipaceratops is one of those tasty mysteries that makes you consider possibilities, flex the brain muscle, so to speak. That it's only one or two bones only makes it more intriguing. Maybe it will never be solved. That's okay. Science is a process, and even dead ends can yield worthwhile insights.

Sometimes when I'm writing I'll imagine someone stumbling across this blog who doesn't care a whit for dinosaurs or paleontology or natural history. They might read about this odd bone from Australia and think that fussing over such a thing is ridiculous. What does it really matter? I can put myself in that person's shoes and understand why digging up ancient bones may seem that way. But I'd ask that person which of the following options is the most ridiculous, when you've pulled a fossil out of the ground.

1. Make up something off of the top of your head.
2. Toss it aside and forget it.
3. Do paleontology.

In my opinion, number three is the only reasonable choice.

Finally, thanks to the commenters yesterday for giving me more to mull over. I've put out a request for a recent paper that offers an alternate hypothesis for Serendipaceratops' identity and may post on that if I'm lucky enough to receive it. If anyone else has any more information that might help, pass it my way - I think I've been pretty diligent about researching this critter, but there's not a lot out there.

Serendipaceratops arthurcclarkei, an Australian Mystery

Serendipaceratops arthurcclarkei is one of the mysteries of dinosaur-kind, lurking Gollum-like in the shadows, threatening to overturn everything we know about the ceratopsians, sowing doubt and confusion. Well, maybe not everything, but possibly their origins and certainly their geographical distribution. In March of 2004, National Geographic News posted a story about the Dinosaurs of Darkness traveling exhibition curated by Monash University paleontologist Patricia Vickers-Rich, and the story briefly mentions the strange new dinosaur from Australia:

Other dinosaurs from southern Australia include Serendipaceratops arthurcclarkei, one of the oldest horned, or frilled, dinosaurs known, which suggests that horned dinosaurs may have originated in the southern polar region.

"That group is most well known from Mongolia, where Protoceratops occurs in the very late Mesozoic/late Cretaceous. The material of Australian origin is early Cretaceous," Vickers-Rich said.

Nat Geo's reporter, John Roach, may have misunderstood Vickers-Rich; her quote doesn't claim that horned dinosaurs originated in Australia (and I've been unable to find any quotes from her that do), but refers specifically to those ceratopsians to which Serendipaceratops is most closely related. It's still a puzzling story.


Leptoceratops by Peter Trusler, via Wikimedia Commons.

Known only from a single ulna - and possibly another pulled from the nearby Dinosaur Cove fossil locale - Serendipaceratops is a huge question mark. Initially skeptical, Vickers-Rich and her partner-in-paleontology, Thomas Rich, decided that the ulna belonged to a ceratopsian based on its strong resemblance to the corresponding bone of Leptoceratops, a well-known Late Cretaceous dinosaur from North America. Lepto is closely related to the more famous Protoceratops, also known only from the Late Cretaceous. Therein lies the problem: if you accept the protoceratopsian nature of Serendipaceratops, it lived tens of millions of years before anything that resembled it. What the heck is it doing in Australia?

It may not seem like a big deal, but consider the following:

• Yinlong, the earliest confirmed ceratopsian, hails from Jurassic China.
• Every other ceratopsian known to paleontologists comes from Asia, Europe, or North America.
• The vast majority of protoceratopsians come from China and Mongolia.

At the time of Yinlong, the continents we know today were still mashed together into the supercontinent Pangaea (click for map). Pangaea was a great C-shaped landmass, with the areas we know as Australia and China at opposite ends. It's possible that ceratopsians might have ranged between Australia and China; it simply would have required populations to travel between those terminal points of the "C" via Africa or South America, and possibly India. You would expect to find something similar to either protoceratopsids or primitive ceratopsians somewhere in these places. To date, none have been found (save for one dubious jawbone from South America that has been lost), but there also aren't many rich, temporally relevant dinosaur-bearing deposits in those regions.

In the recent description of Sinoceratops, the only non-North American ceratopsid, Xu Xing wrote that the apparent endemism of ceratopsids to North America probably reflects gaps in the fossil record rather than actual limitations on the family's Cretaceous range. The mystery of Serendipaceratops is complicated by much larger gaps. And at least Sinoceratops has the decency to have been contemporary with its ceratopsid kin.

It seems simpler to me that the ulna's resemblance to that of Leptoceratops is a coincidence. That's where my money would be, if gambling on paleontology was a sane thing to engage in. Hopefully, the notoriously stingy Australian strata will give up more related material. At the very least, if Serendipaceratops is not a ceratopsian, it's a totally unique Australian dinosaur. That's a pretty good resolution, and still a worthy tribute to the man it was named for.