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A T. rex and Triceratops at Dinosphere

When I was about five years old, my parents took me to a traveling robotic dinosaur exhibit at a local museum. I could hardly wait, but when I finally came face-to-face with the roaring beasts, I was terrified. I loved dinosaurs, but the gnashing teeth and waving horns were just too much for me; I found refuge around a corner to watch them in safety.

The staff at the Children’s Museum of Indianapolis recognizes that as much as children love them, dinosaurs can also be very scary. Not every child will feel comfortable coming face-to-face with a Tyrannosaurus as they exit the dark tunnel leading into their dinosaur exhibit, the Dinosphere, and so they have a little cave where more timid visitors can hang back and play with soft dinosaur eggs.

Those ready to brave the carefully reproduced prehistoric forest will find a museum that not only displays some of the most dynamic dinosaur mounts yet exhibited, but encourages hands-on learning. Children are invited to consider whether Gorgosaurus killed a Maiasaura or was a scavenger, get their hands dirty in a simulated fossil dig, and interact with professional fossil preparators. It sounds like a young dino-phile’s dream, and I wish I was young again to have an excuse to learn and play in such an innovative exhibit!

Figure from research paper about genetic lineage of tetropods

When visitors stroll among the remains of ancient beasts in the dinosaur halls of museums, they often focus on how bizarre they were. With the exception of the more bird-like forms, there is nothing like them alive today: immense sauropods with tails and necks that stretched to the horizon, armor-plated ankylosaurs festooned with spikes, stout ceratopsians ornamented with horns and frills, and gargantuan predatory theropods with banana-sized teeth.

What often goes unnoticed is that we share a deep history with these animals. They are, as spectacular as it may sound, our distant relatives. As reviewed in a new paper in the Annual Review of Ecology, Evolution, and Systematics, about 398 million years ago there was a particular group of fish, the lobed-fined or sarcopterygian fish, the organisms that gave rise to our common ancestor with the dinosaurs. The fish lived in freshwater and had a series of bones in their limbs. These and other factors made them different from fish whose fins were supported by a series of spines or fine rays. Within the sarcopterygians was the ancestor of creatures that would appear at about 385 million years ago, the “fishapods” like Panderichthys and Tiktaalik.

Rather than fins, these fishapods had rudimentary limbs which they used to raise their flat bodies up from the muddy bottom. They were equipped with both gills and lungs, and they were among the first creatures to have necks (in their fish ancestors, the shoulder girdle was attached to the skull, prohibiting flexibility). Despite these adaptations, these creatures were not yet walking on land, but their descendants would. It is difficult to pin down precise ancestor-descendant relationships, but it was this sort of creature that gave rise to the first true “limbed” creatures, the earliest tetrapods, which also had fingers and toes. These were animals like Acanthostega that had an amphibious life at the water’s edge.

Even though limbs had evolved in the water, they allowed early tetrapods to haul out onto land, a place inhabited by plants and invertebrates but no other vertebrates. This did not happen until about 330 million years ago, but when it did, it led to an explosion of diversity. Among the diverse forms was the common ancestor of living reptiles and amphibians as well as mammals and dinosaurs.

Lineages diverged and evolved through time, but our common ancestry can still be seen in our skeletons. We and dinosaurs share body plans based upon four limbs. Although our skeletons have been modified in different ways, we have many of the same types of bones (the bones of our limbs and hands are a good example), and this all goes back to our swamp-dwelling common ancestor almost 400 million years ago.

A mechoraptor sketch by Mark Witton

Scavenging Rights: Over at Archosaur Musings, David Hone muses over a common puzzle for paleontologists: the discovery of an otherwise intact skeleton that has a few bits mysteriously missing. One reason? In any ecosystem (whether Jurassic or contemporary), animal corpses are fodder for scavengers, who pick over the remains and sometimes carry the body parts elsewhere. Hone offers a present day example—a detailed photo narrative of a donkey skeleton in the Mexican desert. (NSFW, if you’re a donkey.)

Field Report: “There are PC cafes everywhere in Asia. Korea lives in them, and the Philippines has taken to them with the intensity of an anomalocaris on a trilobite,” reports blogger Peter Bond. (Congratulations Peter! You are the winner of our first annual Obscure Paleontologist Metaphor of the Year Award.) For those unfamiliar with Peter’s reference, check out the old standby, Wikipedia.

Early Pioneers: The Hairy Museum of Natural History has provided links to the full texts of sample papers from the “Transactions of the Geological Society of London, 1811-1856.” Among the noteworthy documents is Reverend William Buckland’s 1824 article, “Notice on the Megalosaurus or great Fossil Lizard of Stonesfield,” which is acknowledged as the first scientific description of a dinosaur.

Heavy Metal: “So, what’s a newly-submitted Ph.D. student to do with his Saturday night?” asks Mark Witton over at his Flickr blog. Well, if you’re Mark Witton, you catch-up with a backlog of pictures people have asked him to draw (see above). The result is this very cool sketch, “mecharaptor,” a mascot for his friend’s band, Robot Dinosaur. (Not to be confused with the short-lived Seattle grunge band, Robot Therapod.)

Any bidders? Last month, Bob’s Dinosaur Blog reported on how the dinosaur animatronic industry was being hard hit by the sinking economy. Now, Bob presents another worrisome indicator: the plunging market for prehistoric fossils at auction houses. “Earlier this year, a near-complete triceratops skeleton failed to meet the reserve price at a Christie’s auction…and now, according to the Anchorage Daily News, the skull of a prehistoric lion that lived alongside the earliest humans also failed to meet its auction reserve.”

Save the Date:  So, have you bought your 2009 photocalendar yet? Why settle for kitschy calendars with puppies dressed as pilgrims or another one of those “I’m-so-deep-and-in-touch-with-nature” Ansel Adams calendars when, for a mere $23, you can purchase Flying Trilobite’s newly-released 2009 calendar, featuring some truly stunning paleo-inspired artwork.

In Memoriam: A moment of silence, please. Dinochick reports that her favorite hiking boots have passed away (RIP 2001-2008 AD). She memorializes the footwear with a quote from her former professor: “Geology is learned through the soles of your shoes, not the seat of your pants!”

It’s traditional to leave out cookies and milk for Santa Claus on Christmas Eve, but what do you do if Santasaurus is coming to town? I guess that depends on what kind of dinosaur he is. If he’s a predatory theropod, it might be a good idea to pick up some ground chuck and hide the cat, but if he’s an ornithischian, then a bowl of greens would do nicely.

In the children’s book The Dinosaur’s Night Before Christmas, a Night at the Museum-like Christmas story where all the dinosaurs come to life, Santasaurus turns out to be the horned dinosaur Styracosaurus. (Why his sleigh is pulled by other dinosaurs and not a team of Mesozoic mammals, though, is anyone’s guess.) A fanciful retelling of A Visit from St. Nicholas, the book even comes with a CD with paleontologically reinterpreted versions of traditional Christmas songs that will no doubt have parents saying “Turn that racket down!” before the new year.

If lots of kids had their way, though, they would be getting a living dinosaur for Christmas, and that’s the plot of another children’s tale (this time on video) called The Christmas Dinosaur. In this story, a young boy receives a pterosaur (not actually a dinosaur) for Christmas, and it proceeds to be naughty while simultaneously teaching a lesson about being nice. In real life, though, there would probably be plenty of difficulties with claw marks on the couch, piles of dino droppings, and keeping it away from the mailman.

I don’t want to be too much of a Scrooge, though. Happy holidays and merry Christmas to all who will be having visions of dinosaurs dance in their heads tonight!

The movie poster for Land of the Lost, starring Will Ferrell

I was too young to have caught the original Land of the Lost television series, but I do remember the 90’s Saturday morning revamp. Who could forget the adventures of the Porter family in an alternate world stalked by dinosaurs and only helped by their cavewoman friend Christa and ape-man Stink? Actually, come to think of it, I wish I could forget the theme song, which is bound to be stuck in my head all day…

It seems that executives at Universal Studios did not forget about the show, either. Next summer, moviegoers will be able to see funnyman Will Ferrell flee from dinosaurs and the humanoid Sleestaks (Ed. Note — No, not the Sleestaks!) in the big-screen adaptation of Land of the Lost. No trailer has been released yet, but this past week the movie news site Cinematical released the first poster for the movie (included here).

Those who have been waiting for a Jurassic Park IV should take heart. With this year’s Journey to the Center of the Earth, Land of the Lost and Ice Age 3: Dawn of the Dinosaurs due out next year, it seems that the terrible reptiles are still some of the biggest stars on the silver screen.

An oviraptor nest

When paleontologists Jack Horner and Bob Makela named a large hadrosaur that had been found among eggshells and nests in 1979, they called it Maisaura, the “good mother reptile.” The name suggested that the young of this genus were raised with motherly love. Producing eggs would be energetically expensive, and caring for the nest would have helped mothers get a better “return” on their reproductive investment. But what about the fathers?

Egg-laying vertebrates have a variety of reproductive strategies. In some species, males mate with many females and provide almost no parental care, while in others females reverse the roles, leaving their eggs with the male to raise the young alone. In still others, males and females both contribute to raising their young. Different dinosaurs probably exhibited a variety of reproductive behaviors just like living vertebrates.

In a paper released in the journal Science last week, researchers suggested that some dinosaurs found sitting on nests—small theropods of the species Oviraptor, Citipati, and Troodon —might have been males, not females.

How could they tell? Eggs are nutritionally expensive to produce, and like birds, female dinosaurs required calcium and phosphorus to produce egg shells. The source for these minerals came from medullary bone, a spongy looking type of bone lining the inside of the shafts of long bones like the femur. Medullary bone has been found in other dinosaur species like Tyrannosaurus, Allosaurus, and Tenontosaurus. If the dinosaurs on the nests showed evidence of this kind of bone, then they could be identified as females.

When the researchers looked at the cross-sections of femurs from the nesting dinosaurs, they found no medullary bone and little sign of the bone remodeling that goes along with egg formation. What could this mean? There are several possibilities.

One is that the dinosaurs on the nests were females, but they had a different pattern of bone transformation that obliterated the evidence as to their sex. Another is that the dinosaurs on the nests were non-reproductive females — individuals past their prime or not yet laying eggs. This might mean that females cared for the eggs of a mother or sister.

This would have raised what is known as their inclusive fitness, for even if they can’t reproduce themselves, some of the genes they share with their relative can be passed on by helping their kin. It is presently impossible to confirm this. The conclusion of the authors, however, is that the individuals on the nests were male. Given that the results were consistent across individuals from several different genera, making it seem more likely that the same phenomenon was occurring over and over, and given what is seen in birds, the simplest explanation is that the brooding dinosaurs were males.

Oviraptor, Citipati, and Troodon are all maniraptorans, closely related to the dinosaurs that give rise to birds. If the dinosaurs sitting on the nests are really males, then male parental care may have been another trait that appeared in dinosaurs first and was then passed on to birds, where it was modified in many different ways. This hypothesis raises further questions, though.

Did females sit on the nests, too? Did they contribute to raising the offspring, or did they leave males to raise the young alone? What sort of mating system did these dinosaurs have? Further discoveries will be needed, but the present study is a wonderful meld of behavioral observations with breakthroughs in dinosaur bone analysis.

The Austroraptor, as reported in the Proceedings of the Royal Society B

When Jurassic Park was released into theaters, scientists were quick to point out that the film featured super-sized Velociraptor. Even the largest of the dromaeosaurs then known, like Deinonychus, were puny compared to their on-screen cousins. The same year that the film was released, however, the first remains of an enormous, 21-foot-long dromaeosaur named Utahraptor were recovered in, you guessed it, Utah. Velociraptor may have been small, but there were giants in its family tree. Now another “raptor,” just as enormous, named Austroraptor has been announced in the Proceedings of the Royal Society B [Biological Sciences].

Even though many dromaeosaurs are known from the Northern Hemisphere, primarily North America and Asia, they did have some odd cousins that lived in what is now South America. A particular group of these Southern Hemisphere raptors, the Unenlagiinae, had very long snouts and relatively short arms compared to other dromaeosaurs, and Austroraptor falls into this strange group. Even though much of the skeleton is still missing, the recovered skull, leg, vertebrae, and arm bones have told paleontologists a lot about this narrow-snouted predator, which lived 70 million years ago.

Many dromaeosaurs have very long arms, but the humerus of Austroraptor indicates that it had shorter arms more similar in relative size to Allosaurus or Carcharodontosaurus. This is consistent with a trend seen widely among carnivorous theropods; as bodies get bigger, arms get shorter. The leg bones of Austroraptor are also strikingly large, and this also has to do with scaling. Larger animals require thicker and stronger bones to hold themselves up; Austroraptor is not simply a scaled-up version of its smaller relatives like Buitreraptor.

The discovery of Austroraptor has revealed that South America was a center of diversification for predatory dinosaurs. Not only does it illustrate the variety of dromaeosaurs present in South America during the Cretaceous, but it shows that these dinosaurs grew to large sizes and probably came into competition with other predators like the Abelisaurids, theropods like the recently-announced Skorpiovenator. South America during the Cretaceous was definitely a dangerous place to live.

A cat in a dinosaur costume, courtesy of Flickr user windy234

From Robo-Raptor to Pleo to Kota, toy makers seem to love the idea of creating pet dinosaurs. The problem is that these plastic playmates are often exorbitantly expensive and have a limited number of behaviors, quickly losing their charm.

If you really must have a pet dinosaur, there is a cheaper way to do it. If you have a dog, you can dress it up in a “Dogzilla” costume and pretend that you’ve got a pet like a certain modern stone-age family. If you have cats, though, you know well enough not to try doing the same with them. The pictures you get might be cute, but is it really worth the price of your feline friend puking on your bed in revenge?