the bite force of T-rex

I'm on a roll today. Might as well post another.

So obviously, this is a Tyrannosaurus rex. It's so famous I'm afraid I don't really know what else to write about. Oh well, I'll just ramble on about bite forces then.

T. rex has been the focus of many biomechanical studies. Bite force is no exception. However, as much of a celebrity T. rex is, as far as I'm aware, there have only been two studies so far that have attempted to estimate the bite force of T. rex: Erickson et al. (1996) and Meers (2002).

Erickson et al. (1996) had an interesting approach of reproducing bite marks using cast replicas of a T. rex tooth and ramming it into a cow bone. They recorded the forces needed in order to penetrate the bone to different depths. The depths of T. rex bite marks found on a Triceratops ilium was compared to this relationship of puncture depth and forces needed. As a result they found out that a bite force of 6.4 kN were needed in order to to make that bite mark. From the shape and size of the tooth, Erickson et al. (1996) suggested that the bite may have been made from a mid maxillary tooth. So they extrapolated a possible bite force for the posterior-most tooth position. Further, they suggest that up to 30% of the original bite force may have been lost due to several layers of soft tissues that the tooth would have had to penetrate before it reached the bone. In conclusion, they proposed a maximum bite force of 13.4 kN.

Mason Meers (2002) on the other hand employed a much simpler approach. He regressed bite force against body mass and extrapolated the relationship to a 5 tonne T. rex. As a result, his maximum bite force was 183 to 235 kN, an order of magnitude higher than Erickson et al.'s (1996).

So which is closer to the truth?

I would say somewhere in between the two.

Through my own studies, I'm confident to say that Erickson et al.'s (1996) bite force estimate is not really a maximal value. This isn't restricted to just Erickson et al.'s (1996) estimates but for other theropods as well (Rayfield et al. 2001; Mazzetta et al. 2004a, b). With Rayfield et al. (2001) and Mazzetta et al. (2004a, b), their methods in bite force estimation may have the tendency to underestimate. Erickson et al. (1996) on the other hand probably estimated their bite force fairly accurately. The only problem is that the T. rex that produced the bite mark may not have exerted its maximum bite force. The position of the bite on the Triceratops (in the pelvic region) strongly suggests that these bite marks were produced post-mortem and were probably not killing bites but feeding bites. It is unclear just how hard it was biting, but the safe bet is, it was probably just happily munching away at a leisurely (or necessary) bite. I had a chat with Greg Erickson at a conference and he seems to have an opinion along this line as well.

Meers (2002) on the other hand may have overestimated maximum bite force. This is mostly because his slope on the regression equation is closer to 1, or proportional increase of bite force with increasing body mass. So the bigger the animal the stronger the bite. However, my own studies suggest that this slope may actually be significantly lower than 1, so in other words, the bigger the animal, the progressively weaker the bite gets relative to its increase in body mass.

So this puts maximum bite force for T. rex with various body mass estimates at somewhere between 50 to 80 kN.

Penguin and dinosaur cartoon

Dinosaur on the work cartoon

My top 10 biggest sauropods

Good evening to all. Today I will look throw the biggest sauropods. We know that this group of dinosaurs were the biggest creatures on the planet Earth. Many of them are known from only pieces of vertebrae. Ok let's start.

10. The "smallest of the biggest" and may be the most well known sauropod is Diplodocus. This giant from the Late Jurassic was 30 meters long and weighed 25 tons. First when it was described, scientists estimated the size of Diplodocus as 54 meters long and 113 tons weight.

9. Supersaurus probably is an another individual of Apatosaurus, but I will introduce it like a separate genus. Supersaurus was probably 35-40 meters long and weighed up to 35 tons. Ultrasaurus is a synonym to Supersaurus.

8. Seismosaurus was an unusual large diplodocid. It was much larger than its relatives such as Diplodocus and Supersaurus. This giant was 54 meters long and weighed 30 tons.

7. Antarctosaurus is an another titanosaurian competitor. The second specie of this sauropod seems to be one of the largest. Approaching 30 meters long and weighing 60 tons Antarctosaurus is the seventh.

6. The sixth of the largest sauropods is an enormous Sauroposeidon. this dinosaur may have been the highest creature on the planet Earth. It is the biggest Brachiosaurid. It was 17 meters in height.. It was 30-34 meters long and 60-65 tons in weight..  But we are still in finding the largest

5. Paralitian was slightly smaller than the previous competitor. It was 31 meters long. But it was much heavier than the previous two competitors. Paralititan was an African dinosaur that weighed 80 tons. Tis giant was probably hunted by enormous predators like Carcharodontosaurus. I think it must be the fifth.

4.Futalognkosaurus is a South American titanosaurid. Its name means "giant chief lizard". With its size, Futalognkosaurus couldn't have been a good chief. It was 32-35 meters long and 75-80 tons weight. Little bigger than the Paralititan.

3.On the top three largest sauropods is an Argentinosaurus from Argentina. This dinosaur was bigger and heavier than the all previous sauropods. It was 35 meters long and weighed 100 tons. But even this lizard isn't the largest.

2. Introducing the second of the largest creature ever stepped on the Earth. The huge Amphicoelias. It is known from only one part of the vertebrae. This vertebrae is much larger than that of Argentinosaurus. This giant was 60 meters long and 120 tons in weight. but it is only the second.

1. And the winner of my top 10 of the largest sauropods. This dinosaur surpass Amphicoelias in mass by 30 tons. This sauropod was 40-44 meters long. And it is titanosaurid dinosaur from India. Meet the largest creature on the planet Earth. Bruhathkoyasaurus!!!!

Plant-Eating Dinosaur Discovered in Antarctica

For the first time, the presence of large bodied herbivorous dinosaurs in Antarctica has been recorded. Until now, remains of sauropoda -- one of the most diverse and geographically widespread species of herbivorous dinosaurs -- had been recovered from all continental landmasses, except Antarctica. Dr. Ignacio Alejandro Cerda, from CONICET in Argentina, and his team's identification of the remains of the sauropod dinosaur suggests that advanced titanosaurs (plant-eating, sauropod dinosaurs) achieved a global distribution at least by the Late Cretaceous*. 

Their work has just been published online in Springer's journal Naturwissenschaften - The Science of Nature.

Sauropoda is the second most diverse group of dinosaurs, with more than 150 recognized species. It includes the largest terrestrial vertebrates that ever existed. Although many sauropod remains have been discovered in North and South America, Africa, Asia, Australia and Europe, there is no previous record of sauropoda in Antarctica. Other important dinosaur discoveries have been made in Antarctica in the last two decades -- principally in the James Ross Basin.Dr. Cerda and colleagues report the first finding of a sauropod dinosaur from this continent and provide a detailed description of an incomplete middle-tail vertebra, recovered from James Ross Island. The specific size and morphology of the specimen, including its distinctive ball and socket articulations, lead the authors to identify it as an advanced titanosaur.

These titanosaurs originated during the Early Cretaceous and were the predominant group of sauropod dinosaurs until the extinction of all non-bird dinosaurs at the end of the Cretaceous. Although they were one of the most widespread and successful species of sauropod dinosaurs, their origin and dispersion are not completely understood.

The authors conclude: "Our discovery, and subsequent report, of these sauropod dinosaur remains from Antarctica improves our current knowledge of the dinosaurian faunas during the Late Cretaceous on this continent."*The Cretaceous Period spanned 99.6-65.5 million years ago, and ended with the extinction of the dinosaurs.

*Note: The Cretaceous Period spanned 99.6-65.5 million years ago, and ended with the extinction of the dinosaurs.

Deinocheirus

1. Deinocheirus was a lrge theropod dinosaur that lived about 70 million years ago in Mongolia. Its name means "terrible hand". This lizard was really huge. It was 10 meters long and grew up to 10 tons. When it was discovered it was thought that Deinocheirus had been a carnivore and it could kill the prey of almost any size. It used its enormous 40 centimeters long claws to assisting im pulling down branches.

The most well-preserved parts of its fossils are arms. They were about 2.5 meters long with 20 centimeters long claws. Also it had very long neck. It probably fed like sauropods, reaching the highest food. It was 4 meters tall and probably the highest theropod. It could use its claw for defending. The predators like Tarbosaurus could attack this peaceful giant.

The only known fossil remains are a single pair of massive forelimbs and the remains of some ribs and vertebrae. They were found on 9 July 1965 during a Polish-Mongolian expedition to the Gobi by Professor Zofia Kielan-Jaworowska at the Altan Ula III site in Ömnögovi Province. The find was reported by her in 1966

Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America

The well-sampled Late Cretaceous fossil record of North America remains the only high-resolution dataset for evaluating patterns of dinosaur diversity leading up to the terminal Cretaceous extinction event. Hadrosaurine hadrosaurids (Dinosauria: Ornithopoda) closely related toEdmontosaurus are among the most common megaherbivores in latest Campanian and Maastrichtian deposits of western North America.


However, interpretations of edmontosaur species richness and biostratigraphy have been in constant flux for almost three decades, although the clade is generally thought to have undergone a radiation in the late Maastrichtian. We address the issue of edmontosaur diversity for the first time using rigorous morphometric analyses of virtually all known complete edmontosaur skulls. Results suggest only two valid species, Edmontosaurus regalis from the late Campanian, and E. annectens from the late Maastrichtian, with previously named taxa, including the controversial Anatotitan copei, erected on hypothesized transitional morphologies associated with ontogenetic size increase and allometric growth.

A revision of North American hadrosaurid taxa suggests a decrease in both hadrosaurid diversity and disparity from the early to late Maastrichtian, a pattern likely also present in ceratopsid dinosaurs. A decline in the disparity of dominant megaherbivores in the latest Maastrichtian interval supports the hypothesis that dinosaur diversity decreased immediately preceding the end Cretaceous extinction event.