Smithsonian.com

Earlier this month I wrote about a new scientific paper that described an ancient, dinosaur-filled habitat that existed in what is now Siberia. Commenter Naruto raised a point of confusion to many;

I think there is a mistake in this article. The mistake is at the second paragraph, on the last line. “growing understanding that they were not cold-blooded creatures.”, and I think the right one should be “growing understanding that they were cold-blooded creatures.” The “not” shouldn’t be in that line. …

In order to answer this question we have to untangle what phrases like “warm-blooded” and “cold-blooded” really mean, especially since they can be more confusing than helpful.

But are these dinosaurs cold-blooded? Courtesy Flickr user Blush Response

Let’s start with the “cold-blooded” animals like fish, amphibians, and reptiles. Their body temperatures fluctuate with that of their surrounding environment, which means they are ecothermic. This does not automatically mean that these animals are sluggish, though. If the temperature of their surrounding environment is high enough they can be very active (meaning that they are literally “warm-blooded” in those circumstances), and some of these animals even have special physiological mechanisms that help them maintain a high body temperature. Great white sharks, for instance, are able to keep their body temperature several degrees Celsius above the temperature of the cold coastal waters they inhabit.

The animals we often refer to as being “warm-blooded,” by contrast, are more aptly described as being “endothermic.” This means that they generate their own body heat and often keep it at a relatively high, constant temperature. Living mammals and birds are the main examples of this kind of physiology, but there are some species that can switch between being endothermic and ectothermic. Some small birds and bats are endothermic for part of a day or part of the year but ectothermic during other parts. They are so small and burn energy so fast that if they were not able to switch their metabolisms, they would have to constantly collect food or they would die.

So, were dinosaurs ectothermic, endothermic, or something else entirely? Read more after the jump.

(More…)

Name that Fossil! Dinochick challenges readers to identify this specimen found in central Tennessee. Smart money suggests that it’s either a Cruziana or Larry King.

Lone Star Dispute: Bob’s Dinosaur Blog reports that the official state dinosaur of Texas is experiencing an identity crisis. “According to the University of Minnesota’s Peter Rose…the current Texas state dinosaur, Pleurocoelus, has been misidentified.” Rose says the bones are different enough to merit their own genus, Paluxysaurus, named after the Paluxy River near Glen Rose, Texas. (Hey, be thankful it wasn’t found near the Devil’s River in Sonora.) Wikipedia has the complete list of official state dinosaurs.

All Dinosaurs Great.… One of the Everything Dinosaur members of staff was asked the other day: “how big is Brachiosaurus and why when I look this dinosaur up in two books, different size estimates are given”? Found out the answer over there.

…and Small: As we’ve noted before, the mighty T. rex had arms that were so small that some early theorists even suggested they were vestigial organs. To get a sense of just how small the T. rex forearms were, check out this photo of David Hone at Archosaur Musings, posing with the humerus (upper arm bone) of a Tarbosaurus, the Asian cousin of Tyrannosaurus and very similar in size and shape: “As you can see, it is essentially the same size as my own upper arm, yet I am notably not an 8 meter and 6 ton theropod dinosaur.”

Trilobytes: Flying Trilobite has joined the Twitter community, and he’s pondering ideas for new paleo-appropriate labels. Trilotwitobite or Twitobite? (Just a suggestion— you might consider an anagram of “Flying Trilobite Twitter,” such as “Be Loftier Trying Lit Twit”)

Pulp Fiction: Atomic Surgery has uncovered a Golden Age comic book that reveals what really killed the dinosaurs: Not enough meteorites!

Playing Hard to Get: Sci-Fi Wire has posted an interview with Danny McBride, one of the stars of the upcoming Land of the Lost movie, which will reportedly feature high-quality, CGI dinosaurs. Money quote:

How does it feel to see yourself running from dinosaurs?

McBride: It’s pretty weird. You know, I’ve never seen that before. No, that was really my main reason for wanting to do it. I was like, “I want to see what I look like being chased by a T-rex.” And it looks pretty cool. Yeah, I like it.

Read the Fine Print: How can you be sure that large law firms are carefully reading legal documents? One lawyer has a solution: When drafting the Force Majeure clause (better known as “Acts of God”) that excuses parties from liability, he lists war, earthquakes, floods…and “the return of predatory dinosaurs.”

Gigantosaurus skeleton, courtsey of Wikicommons

Who was the biggest predator of them all? For as long as I can remember, Tyrannosaurus rex has been the heavyweight champion of the meat-eating dinosaurs. But its reign would not go unchallenged. Starting in the mid-1990s, excavations in South America and Africa revealed creatures like Giganotosaurus and Carcharodontosaurus that rivaled Tyrannosaurus in size. They, along with Spinosaurus, and Mapusaurus are the current contenders for largest theropod. Together they appear to represent the upper limits of how large these predatory dinosaurs could get.

Paleontologists Francois Therrian and Don Henderson reviewed this problem in the paper “My Theropod is Bigger Than Yours… Or Not: Estimating Body Size From Skull Length in Theropods” which appeared in the Journal of Vertebrate Paleontology. Although there are many skeletons of Tyrannosaurus and scientists have a relatively complete view of what its skeleton was like, we are not so lucky with other theropods. In some cases, that of Spinosaurus in particular, much of the skeleton has yet to be found and body size must be estimated.

In developing a method to estimate body length and mass based upon skull size, Therrian and Henderson found that as theropods grew larger, their skulls became proportionally longer. This makes sense because the largest of the theropods were large-headed hunters that used their heads to attack, kill, and consume prey. (The giant Therizinosaurus was an exception to this, as its relatives had large arms, long necks, and small heads.) With this relationship established, the researchers could estimate the body length and mass of the large predators only known from skulls.

Although they stressed that they estimates were provisional and required more complete skeletal material to confirm, Carcharodontosaurus (43.5 feet; 33,345 pounds) and Giganotosaurus (42.6 feet; 30,438 pounds) appeared to be longer and heavier than Tyrannosaurus (39.3 feet; 20,085 pounds). Spinosaurus (41.2 feet; 26,428 pounds) was also slightly larger than Tyrannosaurus but not quite so big as had previously been estimated (47 feet;46,049 pounds).

Based upon these estimates, the little-known Carcharodontosaurus appears to be the “winner,” but time will tell whether this is true. Even if a complete skeleton is ever found, it is not likely to represent the largest member of this genus. Individual animals vary in size, and what we are really comparing are the largest members of different groups. There were probably some adult Tyrannosaurus that were longer and/or heavier than adult Giganotosaurus and vice versa; there was no single set length or weight that all individuals attained. What is clear, though, is that all of these dinosaurs were top predators in the places and times in which they lived and we would be little more than a snack to any of them.

Cacops fossil discovered in Oklahoma

On July 23, 2005, amateur paleontologist Tony Morris was looking for fossils with friends in a part of Oklahoma where a mining operation had uncovered a wealth of fossil fragments. He found a piece of rock with a jaw sticking out of it. Could there be more of the skull of this creature inside the rock?

Morris spent a month meticulously scraping away the rock and eventually revealed the skull of a small lizard-like creature. According to NewsOk, Morris then contacted University of Toronto paleontologist Robert Reisz about it.

Now, Reisz has concluded that the skull represents a new species, an amphibian related to the genus Cacops. This species of big-headed vertebrate looked like a cross between a frog and a lizard and lived about 280 million years ago, before the dinosaurs in the Permian period. Reisz is working on a paper on the find.

The recent case of amateur paleontologist Nathan Murphy illustrates how complicated fossil-collecting can be. Murphy ran a for-profit organization called the Judith River Dinosaur Institute, which took paying customers to dig at fossil sites. According to a New York Times report, Murphy had an arrangement in 2002 to dig on the Montana land of Joann and Howard Hammond, under which he would share profits from his business with them. During that year, one of Murphy’s customers found a Velociraptor-like dinosaur there.

That customer has since said that Murphy told him to keep the discovery secret from the Hammonds, according to the Times. In 2006, Murphy showed parts of the raptor fossil to colleagues and said he had found it only recently and at a different site. Then his customer talked about the find to the Hammonds—who, it turns out, did not own, but rather leased the land on which the fossil was found. The owner of the land filed a complaint against Murphy, who is scheduled to stand trial on theft charges in March. He told the Times that he had assumed he had an agreement to excavate on the property, but that he felt that he had no choice but to plead guilty.

Even under the best of circumstances, determining who can remove fossils from what where can be a tricky business. Every year paleontologists must carefully navigate the tangle of laws and restrictions on fossil collecting. Even though scientists have been clamoring for a more clear-cut system for years, none is on the horizon.

An illustration of the minotarasaurus

During the Late Cretaceous, 100 to 65 million years ago, the area now known as the Gobi Desert was a dangerous place, stalked by small hunters like Velociraptor and massive tyrannosaurs like Tarbosaurus. But one group of herbivorous dinosaurs appears to have done well in this harsh place. Several kinds of ankylosaurs are known from these deposits, and a new genus, Minotaurasaurus, has just been described.

This new ankylosaur was described, in the journal Current Science (PDF), from a complete skull—but not one that was found out in the field. Instead, paleontologists noticed it when it was put on display at the Victor Valley Museum in California. From the sediment that still encased part of the skull and other evidence, the researchers concluded that this dinosaur came from the Cretaceous deposits of the Gobi desert.

If this analysis is correct, Minotaurasaurus may have lived alongside other well-known ankylosaurs from the region, such as Tarchia, Pinacosaurus and Saichania. In fact, the skull of Minotaurasaurus is strikingly similar to that of Saichania. Is it possible that the “new” ankylosaur is a representative of the already known genus? This specimen might fall within the range of variation exhibited by the better-known genus, and further study will be needed to determine what this new skull represents.

In 1836, the Amherst College geologist and natural theologian Edward Hitchcock published a description of strange, three-toed tracks found in the blood-red sandstone of the Connecticut Valley. The tracks were well-known to local residents; some members of the Lenape tribe believed that they had been made by an ancient monster, and European settlers often described them as turkey tracks. Hitchcock, who had found out about the tracks by the naturalist James Deane, believed that they were made by gigantic ostrich-like birds that lived long ago.

The skeletons of the creatures proved elusive—but when they were discovered years later it turned out that the trackmakers were not birds, but early dinosaurs. Hitchcock didn’t live to see this discovery, but the strange impressions enthralled him all the same. Soon after he published his description of the tracks, he also published, under a pseudonym, a poem celebrating them in the magazine The Knickerbocker. In “The Sandstone Bird,” a sorceress (Science) conjures up one of the ancient birds, but the giant avian, disappointed at the degenerate state of the world, vanishes back into the void without a trace—a telling reflection of one scientist’s frustration that he could not confirm the form of the real “sandstone birds.”

Read the full poem after the jump.
(More…)

Even though the basics of finding fossils in the field has not changed much since the dawn of paleontology, today’s paleontologists have a few advantages over their 19th and early 20th century counterparts. Aside from being able to drive over tough terrain and transport large slabs of bones with heavy machinery, one of the most important tools a paleontologist can have is a cell phone.

The site Mobile Maven recently posted a list of all the ways in which cell phones might be of use while out in the field. You will need some fancier hardware like an iPhone, but top-tier cell phones can be used as GPS units or cameras and can send e-mail in a pinch. An iPhone can’t replace dedicated GPS units or cameras, but when you’re working in the field it doesn’t hurt to have something that can double as a spare.

If you would rather not take your iPhone into the field, though, you can still put some dinosaurs on it. Pangea Software has released a game called Nanosaur 2 for the iPhone in which you play a pterosaur sent from the future to save dinosaur eggs. It sounds like fun, but given that my phone can barely run Tetris, I don’t think I’ll be playing it anytime soon.