Smithsonian.com

The exceptionally-preserved skeleton of Darwinius. From PLoS One.

This week news services were all a-twitter about a 47-million-year-old fossil primate from the famous Messel deposits of Germany. Named Darwinius masillae and described in the journal PLoS One, the lemur-like primate was heralded as being a transitional form between a group of extinct primates called adapids and anthropoid primates (monkeys and apes). As it turns out the fossil may not be all it has been cracked up to be, but it is still a spectacular find that represents one branch of the primate radiation that occurred after the mass extinction that killed off the dinosaurs at the end of the Cretaceous. Creatures like Tyrannosaurus perished, but primates survived.

Tracing the record of the earliest primates is a challenge. Since primates started off small and lived in forested habitats their fossils are extremely rare, and most fossils that are found are teeth. This can make comparisons between these creatures difficult, and the relationships among early primates or primate-like creatures are controversial. The fact that some molecular studies places the origin of primates even further back in the Cretaceous, about 85 million years ago, makes things even more complicated as no verifiable primate fossils have yet been found from that age. Despite these complexities, however, scientists do have a broad outline of early primate evolution.

One of the earliest primate-like creatures was Purgatorius, a tree-shrew-like mammal that lived right around the end of the Cretaceous 65 million years ago. Whether it was one of the first primates or only closely related to the first primates is still controversial, but it does seem to represent what the ancestors of primates were like during the time that dinosaurs were the dominant land-dwelling vertebrates.

After the mass extinction, mammalian evolution exploded. Mammals were no longer under the feet of dinosaurs, and among the groups that diversified were primate-like creatures called plesiadapiformes. Whether these creatures were true primates or just very primate-like is still being debated, but they underwent a boom and bust during the Paleocene (about 65 to 55 million years ago). In many ways these creatures were somewhat squirrel-like, with clawed hands and eyes on the sides of their heads, but at the very least they seem to be the closest extinct relatives to other primates.

The creatures that are regarded as “true” primates flourished during the Eocene (about 55 to 33 million years ago), and can largely be placed into two groups: the adapids and omomyids. The adapids were lemur-like primates, while the omomyids closely resembled living tarsiers, but both had forward-oriented eyes and adaptations to life in the trees. Both these groups are relevant to yesterday’s big announcement.

According to the new paper, Darwinius is an adapid, and many scientists presently regard this group as being more closely related to modern lemurs and lorises than to monkeys or apes. Many paleontologists who study extinct primates favor omomyids and ancient tarsiers as being closer to monkeys and apes, but the authors of the new paper don’t think so. In the paper itself they claim that Darwinius belongs to the same large group of primates, haplorrhines, as tarsiers, monkeys, and apes, thus placing adapids in a position to potentially become our ancestors. This conclusion has caused the scientists involved in the study and the popular media to herald it as a “missing link” that connects us to other primates.

Unfortunately, however, the scientists who wrote the paper did not conduct a detailed evolutionary analysis of the new fossil or its relationships to other primates. The fossil is spectacular, the first fossil primate to be find in such a state of exceptional preservation, but it has been oversold by the History Channel (who organized the media hype) and the scientists involved in the study. They simply did not do the work to support the conclusions they drew from the fossil, and the real relationship of Darwinius to other primates will have to wait for further studies.

A pair of Iguanodon on a riverbank, from Current Literature.

Outside of Hollywood films, dinosaurs like Tyrannosaurus and Triceratops never coexisted with humans, and no case can be made that The Flintstones is an accurate depiction of prehistory. That has not stopped young-earth creationists from maintaining otherwise, though, and this has led to some rather silly statements.

Attempts to squeeze paleontology into a literal interpretation of Biblical timelines have a long history. A 1912 issue of Current Literature featured some excerpts from a book about paleontology called Evolution in the Past by H.R. Knipe. The article itself is not terribly interesting, but the captions accompanying the article’s illustrations are. Several dinosaurs and extinct mammals are featured and each caption explains the benefits or dangers these animals would have posed to early humans. The caption beneath a pair of Iguanodon reads:

THE TERROR OF THE RIVERBANK IN THE GEOLOGICAL PAST

The iguanodonts [sic] fought with their tails, and in the course of the combat rendered life precarious in the vicinity for all living creatures. It is difficult to see how prehistoric man could have made his abode along the main streams while these monsters flourished.

In truth, early humans had nothing to fear from Iguanodon. The herbivorous dinosaurs had been extinct for about 114 million years by time the earliest humans evolved in Africa. To suggest otherwise would require some startling evidence indeed! It should be noted that the tone of some of the captions makes it seem like they are not to be taken seriously, but even if this is true they are not out of line with what many creationists truly believe. (Don’t even get me started on their ideas about what Tyrannosaurus would have eaten in the Garden of Eden.)

If humans did live alongside dinosaurs, though, it does raise the question of how our kind survived. Why wouldn’t our species have been consumed by a horde of hungry tyrannosaurs, or our early attempts at agriculture destroyed by herds of sauropods? There is simply no record of any kind of Dinotopia, and most of the “evidence” creationists offer are like Rorschach tests; they see what they want to see. Watching humans flee from dinosaurs might make for exciting cinema, but it is absolutely awful history.

Nicki Conaway next to her creation

Studying dinosaur fossils can be hard work, but imagine building a dinosaur from scratch. That was the task given to St. Louis Community College art student Nicki Conaway, who created a 12-foot-tall Tyrannosaurus skeleton (nicknamed “Lola”) for a production of the play Pterodactyls at her school. The sculpture was mostly constructed of Styrofoam.

Don’t be deceived by the title of the play, though. You won’t see people in pterosaur costumes running about the stage. Instead Pterodactyls (which ran last month) was a black comedy about a dysfunctional family. The Tyrannosaurus comes in when one of the characters finds its bones in the backyard and is more interested in putting them together than in paying attention to the rest of the family. I’m sure it was an interesting performance, but I would have loved to have seen an all-pterosaur cast.

Carnivore, by Leigh Clark.

If late night B-movies have taught me anything, it is that radiation makes things grow very big really, really fast. This is not true, of course, but it is a standard convention of cheesy science fiction, and it is a theme carried on by Leigh Clark’s novel Carnivore.

The story unfolds at a remote Antarctic research station where a team of scientists has brought back a Tyrannosaurus egg they found frozen in ice. At one point someone says “Gosh, we shouldn’t put any of that radioactive waste we have lying around next to that egg or it will grow very fast!” But of course this is just what the human villains of the story do. Before you know it the little Tyrannosaurus is a full-grown terror, gorging itself on the hordes of nameless characters that seem to appear out of nowhere at the outpost.

I would mention the main characters of the novel, but there is not much point. Almost everyone falls prey to the Tyrannosaurus in gruesome fashion. Indeed, Clark’s antagonist is a very messy eater, and it is no wonder that it eats so many people since it can’t seem to keep those it captures in its mouth for very long. If done right the descriptions of blood and gore could have been chilling, but instead the novel jumps from one scene of over-the-top carnage to the next.

Carnivore mostly serves as an excuse to have a Tyrannosaurus munching on scores of hapless victims in the Antarctic, but a more effective thriller is Lincoln Child’s new novel Terminal Freeze. In some ways it is quite similar to Clark’s book (a team of scientists finds a prehistoric killer locked in ice), but Terminal Freeze is more fully developed. The Arctic base where Child’s novel is set is described in vivid detail, making it easy to imagine his monster slinking down the dark, chilled hallways. As it turns out, Child’s creature is not a dinosaur but an unknown kind of mammal, but it is just as terrifying as Clark’s more famous antagonist.

While the idea that dinosaurs (or other monsters) might be preserved alive in ice for millions of years is a bit silly, we do know that dinosaurs inhabited cold habitats within the Arctic Circle. The past year has seen the publication of several papers describing the diversity of dinosaurs in the cold northern reaches of the globe. While novelists still have to figure out how to close gaps of tens of millions of years to bring dinosaurs and humans together, a tyrannosaur trotting through the snow is not such a far-flung idea after all.

A sneak peek at what Dinosaur Train will look like. From Playthings.com

Dinosaurs and trains might not seem to have much in common, but the television network PBS will soon be mashing them together in a new children’s show called “Dinosaur Train.” Right now details are scant, but it looks like the show will be set in a computer animated world where characters will teach children about natural history and paleontology. Every now and then they will even hear from a real paleontologist, the University of Utah scientist Scott Sampson, although most of the show will feature as-yet-unannounced characters. If you can’t wait to start traveling down the dinosaur track, though, you can always pick up some dinosaur shoes and make tracks of your own in the meantime.