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The skull of a mounted Tarbosaurus. Photo by Jordi Payà, from Wikipedia.

The road home for an illicit Tarbosaurus is bound to be a long one. Earlier this summer, federal agents seized a skeleton of the tyrannosaur Tarbosaurus that had been put up for auction in New York City. The sale price for the dinosaur topped $1 million, but, as was long suspected and was soon made clear, the dinosaur was illegally smuggled into the United States. Even worse, the skeleton itself was almost certainly illegally excavated from Mongolia and subsequently smuggled out of the country. Mongolian officials, professional paleontologists, lawyers, and United States officials moved quickly to prevent the dinosaur from disappearing into the collection of the tyrannosaur’s prospective buyer.

I see these events as a victory. The fossil black market has robbed many countries of their natural history heritage, especially Mongolia and China, and I was glad to see so many concerned activists work together in the hope that the Tarbosaurus might be returned. As expert paleontologists have concluded, the Tarbosaurus undoubtedly came from Mongolia–a country with strict heritage laws about who can collect fossils, what can be collected, and what subsequently happens to the fossils. All the evidence accumulated so far supports to idea that the Tarbosaurus was looted from Mongolia. But the man who assembled the controversial Tarbosaurus doesn’t agree, and has filed a claim on the dinosaur. Eric Prokopi, who obtained the Tarbosaurus and stood to profit from the auction, believes that the dinosaur is rightly his.

As reported by Wynne Parry at LiveScience, Prokopi and his attorney are trying to defend the sale of the Tarbosaurus by drawing a distinction between raw fossils and the reconstructed end product. “We are just trying to create a factual distinction between a fossil which is imported and a finished piece which is what was being sold at the auction,” Prokopi’s attorney Michael McCullough said.

But this strategy entirely misses the point. Prokopi obviously put a great deal of time, money, and effort into the tyrannosaur skeleton, but that does not change the fact that the skeleton was almost certainly illegally excavated and, as customs documents demonstrate, smuggled into the United States through a false description. How hard Prokopi worked is absolutely irrelevant. And, frankly, Prokopi should have known better than to put so much effort into a significant dinosaur specimen when he admittedly had no idea where the specimen came from or how it was collected. The bottom line is quite simple–the Tarbosaurus was illegally removed from its home strata, and it should be returned to its country of origin of soon as possible.

Allosaurus is one of the best-known dinosaurs, but it’s rare to find an extensive record of any single dinosaur genus. And there are some dinosaurs that we may never meet at all. (Photo taken at the Natural History Museum of Utah by the author)

During the past two centuries, paleontologists have discovered and named over 600 different non-avian dinosaur genera. At first glance, that might seem like a lot of dinosaur diversity (especially since only a handful of dinosaurs are well-known to the public). But it’s really just the tip of the Mesozoic iceberg. New dinosaurs are being described on a near-weekly basis, and, as estimated by paleontologists Steve Wang and Peter Dodson in 2006, there may have been over 1,800 different genera of dinosaur present on earth during their 160 million year reign between the Triassic and the end of the Cretaceous. Most dinosaurs remain undiscovered.

But will we ever find all the dinosaurs? I don’t think so.

The fossil record is a history biased by the circumstances required for preservation and discovery. Paleontologists and geologists have recognized this for over a century and a half.  As Charles Darwin, following the argument of his geologist friend and colleague Charles Lyell, pointed out in On the Origin of Species, the geological record is “a history of the world imperfectly kept and written in a changing dialect.” Consider the world’s strata to be like pages of a book that record the comings and goings of species over time, Darwin wrote. “Of this history we possess the last volume alone, relating only to two or three countries,” Darwin lamented, and “Of this volume, only here and there a short chapter has been preserved, and of each page, only here and there a few lines.”

Let’s apply this to dinosaurs. Of all the non-avian dinosaurs that ever existed, only a few died in circumstances amenable to fossil preservation. Dinosaurs bodies had to settle in a place where sediment was being laid down – a river, lake, dune-covered desert, floodplain, lagoon, or similar environment – to be preserved for the rock record. This means that we know a lot about lowland dinosaurs who lived near bodies of water, but dinosaurs that lived in upland habitats are not so well represented. These dinosaurs, who inhabited ancient mountains and similar habitats, were living in places where rock was being stripped away rather than new sediment laid down. In other words, upland dinosaurs didn’t live in the kind of habitats where they were likely to become preserved. There were undoubtedly entire populations, species, and even genera of dinosaurs that may have never entered the fossil record.

And preservation in the fossil record alone isn’t a guarantee that a particular dinosaur genus will be discovered. Of all the dinosaurs preserved in the rock, only a few are accessible in exposed portions of rock around the world. Fewer still are intact enough to identify and collect. The contingencies of fossilization, history, and our ability to search for fossils conspire to blur our picture of dinosaur diversity.

The picture isn’t entirely negative, though. There are swaths of dinosaur-bearing rock that are, as yet, little explored, and even extensively-searched areas can still yield surprises. I have no doubt whatsoever that paleontologists will continue to discover and describe previously-unknown dinosaurs for many decades to come. And, more than that, each new dinosaur tweaks our picture of dinosaur relationships and the details of when and where particular groups evolved. Using this knowledge, paleontologists can go back to the rock and target specific areas where new dinosaurs might be found. We probably won’t find every single dinosaur genus that ever existed, and we may not have an intricately-detailed record of every genus that we’re lucky enough to discover, but there is still an overwhelming array of dinosaurs out there waiting to be found.

A cast of the sauropod Diplodocus at the Utah Field House of Natural History in Vernal, Utah. Our current understanding of sauropods like this differs greatly from hypothetical restorations of "living dinosaurs" in Africa. Photo by the author.

In the annals of science fiction, humans and non-avian dinosaurs have been brought together in a variety of ways. Genetic engineering experiments and time travel are probably the most common these days, but I have always had a soft spot for tales of “lost worlds.” What could be more fantastic than dinosaurs that somehow escaped extinction and persisted in some isolated spot for 65 million years? My childhood self really wanted someone to find a living Tyrannosaurus, Apatosaurus, or Triceratops in some remote locale, and that wish was fed by reports that one elusive dinosaur was hiding in Africa.

First thing first—living dinosaurs certainly do exist. We know them as birds, and a combination of fossil discoveries and laboratory research has confirmed the evolutionary connection between birds and feather-covered maniraptoran dinosaurs. But from time to time, people have proposed that non-avian dinosaurs may also still be hanging around.

The most famous of the supposed living dinosaurs I heard about was Mokele-mbembe. This unknown creature—often restored as a swamp-dwelling, tail-dragging sauropod akin to old restorations of “Brontosaurus“—is said to inhabit the dense jungle in what is now Cameroon and the Democratic Republic of the Congo. At least, that’s the way I was introduced to the legendary animal in the late 1980s. A blurry photograph of a lump in a lake and an ambiguous sound recording made by Herman Regusters during a 1981 expedition to find the animal were cited as possible evidence that a semi-aquatic sauropod was swimming around Lake Tele, and the feature film Baby: Secret of the Lost Legend fleshed out the hypothetical dinosaurs. Tall tales and legends of Mokele-mbembe had been circulating for decades before, and sensationalist basic cable television programs still fund expeditions to try and find the animal from time to time.

Is there any good evidence that a sauropod still wades through the muck of African swamps? Sadly, no. I would be thrilled if a living, non-avian dinosaur really did turn up somewhere, but such a fantastic find would have to be backed up by equally fantastic evidence. Despite the fact that multiple expeditions have been sent to the Democratic Republic of the Congo over many years, there is no solid evidence that Mokele-mbembe is a dinosaur or even a real, unknown species of animal. I seriously doubt anyone will ever find any evidence of such a creature at all, and part of the reason why related to a paper published by University of Queensland zoologists Diana Fisher and Simon Blomberg last year.

The major message of Fisher and Blomberg’s study was positive: Some modern mammal species thought to be extinct may still survive in small, hard-to-find pockets of their former ranges. But the researchers also noted that the effort put into finding supposedly extinct species makes a difference as to whether we should expect to find those animals. The researchers found that species that still survived were often found after three to six searches, but if more than eleven searches were made with no results—as is the case for the Tasmanian tiger and Yangtze river dolphin—then the species is probably actually extinct. Since so many searches have been made for Mokele-mbembe with no solid results, I don’t think that there’s actually any large, hidden species there to find.

There is a flipside to that argument, although it also doesn’t bode well for the rumored dinosaur. Many of the searches for Mokele-mbembe have been made by self-described explorers who have little to no relevant field experience in tracking and studying wildlife. Some of these folks are even religious fundamentalists who are striving to somehow undermine evolutionary theory. Their credibility is highly suspect, but you would think that at least one group would have blundered into the animal by now. After all, there has to be a population of animals which would be leaving tracks, scat and occasionally bodies. The evidence for huge creatures living in the swamp should be readily apparent, and the best the many dinosaur hunters can come up with are tall tales and misshapen globs of plaster that look nothing like the tracks the casts are claimed to be.

But the most obvious problem is that there’s no trace of sauropods in the fossil record—at all—in the 65 million years since the end-Cretaceous extinction. Nothing. The last of these dinosaurs died out long ago, and there is not even a scintilla of evidence that sauropods survived past the close of the Mesozoic. If sauropods survived at all we would expect to find some indication of their existence in the fossil record. These were not small animals or creatures that were hidden away in the deep sea. Given the number of terrestrial fossil deposits and they way they have been sampled, Cenozoic sauropods would have turned up by now if they had survived.

There are plenty of other problems with the idea that there’s a sauropod trundling around in the swamps of the Congo Basin. One of the most ridiculous aspects of Mokele-mbembe stories is that the supposed dinosaurs resemble what the searchers expected sauropod dinosaurs to look and act like based on inaccurate restorations. The hypothetical dinosaurs act just like their counterparts in old Charles R. Knight and Zdeněk Burian paintings. Actual, living sauropods would have looked markedly different from those old restorations, and according to recent research, sauropods would have been really lousy swimmers due to the considerable volume of air-filled spaces in their bodies. A sauropod would not be able to act like a crocodile and hide underwater as Mokele-mbembe supposedly does. The weakness of the “Mokele-mbembe as sauropod” hypothesis is underscored by the fact that the supposed anatomy and behavior of the animal is clearly based on outdated images of dinosaurs. As Darren Naish pointed out in his brilliant April Fool’s Day post on Mokele-mbembe from this year, the idea that the animal was an old-school, tail dragging sauropod grates against everything we have learned about sauropods during the past three decades.

Paleontologist Don Prothero also took a few good whacks of Mokele-mbembe in a recent Monster Talk episode. Not surprisingly, Prothero points out that many of the reports about the animal are extremely inconsistent. A number of supposed sightings don’t refer to anything dinosaur-like at all, and even those that do are inconsistent and ambiguous. On top of that, Prothero and the show’s hosts bring up the fact that fanatics in search of Mokele-mbembe can easily misconstrue what local people might be saying about the animal because of a lack of shared cultural background and other translation problems. While visiting explorers often use the term “Mokele-mbembe” to refer to a supposed dinosaur or similar animal, the word can also refer to something that is not real or has no physical manifestation. If film crews and self-described explorers keep passing through and spending money in the region, it’s not surprising that people will tell the monster hunters what they want to hear.

The take-home lesson is this: If you want to find sauropods, sign up to volunteer on a professional fossil excavation with well-trained scientists.

Dinosaur, Colorado's Triceratops. Photo by author.

While spending the week at Utah’s Dinosaur National Monument looking for fossils with the Utah Museum of Natural History field crew, two graduate students and I took one afternoon off to visit nearby Dinosaur, Colorado. The small town has certainly taken dinosaurs as its mascots. In addition to the streets named after dinosaurs—you can travel down Stegosaurus Freeway or amble along “Antrodemus” Alley—the town’s main drag is festooned with a number of goofy-looking dinosaurs, including a strange Triceratops. The sculpture has the standard accoutrements of the famous dinosaur—the three horns and the frill—but the super-long snout, molars and tongue make this playground ornament one creepy Triceratops.

Have you seen a prehistoric creature in an unusual place? Submissions of dinosaurs—and other ancient beasts—should be sent to dinosaursightings@gmail.com.

A baby dilophosaurus at the Hogle Zoo. Photo by Brian Switek

Animatronic dinosaur exhibits have made a comeback during the past few years. Zoos all over the country have hosted menageries of jerking, growling dinosaurs. The Hogle Zoo in Salt Lake City, Utah is one of the latest to host a collection of robo-dinos, and when I heard about the temporary Zoorassic Park exhibit I thought I would check it out.

Even though I feel ambivalent about robotic dinosaur exhibits, kids obviously love them. Hordes of children screamed and jumped up and down at the sight of the Styracosaurus, Allosaurus, Parasaurolophus and, of course, Tyrannosaurus robots spread throughout the zoo, and quite a few obviously loved being sprayed by a spitting Dilophosaurus. The dinosaurs were a hit.

But the dinosaurs are only just one part of Zoorassic Park. Two other components add a significant amount of substance to the garden of dinosaurs: a small-scale museum exhibit featuring fossils from the nearby Utah Museum of Natural History and an indoor pathway that places modern creatures in the context of the prehistoric past. Real fossils and live animals were both used to make paleontology relevant to the visitors, though, admittedly, kids appeared to be far more enthusiastic about the snarling dinosaurs. This underscores the challenge of all these exhibits. Moving, roaring dinosaurs might help bring visitors into the park, but turning that attraction into a teachable moment is a difficult task.

View more dinosaurs at the Hogle Zoo in our gallery.