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.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.
"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.
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.
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.