Spinosaurus: A huge predatory dinosaur, built to swim

Source: Amina Khan/Los Angeles Times

Dinosaurs ruled the land for millions of years. Now scientists have discovered a fearsome species that could have wreaked havoc in its prehistoric waters.

An unusual fossil whose parts were flung across two continents appears to be the first known semi-aquatic dinosaur, according to a report published Thursday by the journal Science.

Measuring 9 feet longer than a Tyrannosaurus rex, the 95-million-year-old Spinosaurus aegyptiacus would have been the largest predatory dinosaur to walk the Earth. But it had several features that strongly suggest a life spent largely submerged in the water, including nostrils pushed toward the top of its skull and diagonally jutted teeth ideal for snapping up fish.

“It was not a balancing, two-legged animal on land,” said study coauthor Paul Sereno, a paleontologist at the University of Chicago. “It would have been something very peculiar.”

The differences between this Spinosaurus and other theropods are apparent from head to toe. Most theropods, like T. rex, ran on two powerful legs and had small, spindly arms. By contrast, the 50-foot-long Spinosaurus had muscular arms with blade-like claws that could have nabbed slippery prey, and shorter legs that were ill-equipped to walk on land.

The fossil has odd openings at the front of its long, thin snout that could have housed pressure sensors, rather like those on alligators and crocodiles that help them sense movement to hunt in murky waters. The marrow holes in its bones are closed, making them very dense — an adaptation seen in aquatic animals including penguins to control buoyancy in the water.

The dinosaur’s feet were wide and flat and might even have been webbed. And the animal’s center of mass was pushed far forward, terrible for moving on land but excellent for swimming.

“It’s about time that they found a dinosaur that was semi-aquatic,” said Hans Thewissen, an anatomist at Ohio Medical University who was not involved in the research. Considering that dinosaurs were a dominant group during their time on Earth, it would be strange if they ceded the prehistoric rivers and seas to fish and marine reptiles, such as the mosasaur or plesiosaur.

“I’m not surprised,” Thewissen said, “but I’m delighted that they found it.” Paleontologists David Martill, Nizar Ibrahim, Paul Sereno and Cristiano Dal Sasso, left to right, in the field. A partial spine of Spinosaurus can be seen in the foreground.

Like other known spinosaur species, S. aegyptiacus sported a bony “sail” on its back, a dramatic display that would have stayed above the water as it swam. James Kirkland, a Utah Geological Survey paleontologist who was not involved in the discovery, thinks this creature might have used its sail literally, to keep moving without alerting other animals to its massive presence.

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The first Spinosaurus skeleton was discovered in Egypt in 1912 and described by a German scientist, Ernst Freiherr Stromer von Reichenbach, in 1915. Stromer took the bones home, only to have them destroyed in an Allied bombing raid in 1944. Aside from the careful drawings he made and the occasional photograph, his discovery was obliterated. But in 2008, University of Chicago paleontologist Nizar Ibrahim was working in Morocco when a Bedouin fossil hunter approached him with a cardboard box of sediment-encrusted bones. Ibrahim looked in the box, noting a strange bladelike fossil with a red line running through it.

Later, he visited a museum in Italy and heard about some peculiar fossils in the basement that had been sent from Morocco.

“My jaw dropped,” said Ibrahim, the lead author of the Science report. It was a rich collection of leg, foot and rib bones, along with spine pieces marked with the same red line.

Ibrahim had already wondered whether the bones were from a Spinosaurus. Now he suspected the two collections, spread across two continents, had come from the same animal. But he didn’t know where the bones had been found; without that information, it would be impossible to tell when and where the animal had lived.

So Ibrahim set out to find the man with the box. He didn’t have his name or phone number, but recalled that the man had a mustache. Armed with that paltry bit of information, Ibrahim and his colleagues returned to the Moroccan oasis town of Erfoud and searched for him, with no luck.

“Towards the end of our mission impossible, we were just sitting in a cafe in Erfoud, sipping mint tea and I just saw all my dreams going down the drain,” Ibrahim said. “At that very moment just when everything seemed to be lost, a person walks past our table.”

Sure enough, it was the man with the mustache. Fossil hunters are loath to reveal their dig sites, for fear that others will try to get a piece

of the action. But Ibrahim laid out his scientific credentials and persuaded the man to take him to the spot in the Kem Kem beds.

Ibrahim also traveled to the Stromer family castle in southern Germany, where Stromer’s granddaughter gave Ibrahim the decades-old sketches of the fossil. Ibrahim and his colleagues were able to reconstruct a model of the Spinosaurus skeleton, borrowing bones from related species to fill in the missing pieces.

Lindsay Zanno, a paleontologist at the North Carolina Museum of Natural Sciences in Raleigh, cautioned that the fact that the skeleton was assembled from many different sources casts a little doubt on the accuracy of the reconstruction’s size and shape.

“We have to be very careful about presuming that we know exactly what this animal looked like,” said Zanno, who was not part of the study team.

That said, she added, “I really didn’t expect there to be this much compelling evidence” of an animal adapted for life in the water — and especially one with such a hodgepodge of features. “I find the proportions of this animal to be really bizarre.”

Ibrahim, who is half Moroccan and half German, said he feels that he’s helping complete Stromer’s century-old legacy. The bones will be returned to Morocco, he said, to help jump-start the country’s museum program

Possible Response Questions: • Should we care that a new species of dinosaur was discovered? Yes? No? Explain. • What is your theory on why dinosaurs became extinct? Explain. • Select any passage and respond to it.

Should we care that a new species of dinosaurs was discovered? Yes? No? ExplainA new species of dinosaurs have been discover, and it matters. Dinosaurs were a big part of history. "Dinosaurs ruled the land for millions of years. Now scientist discovered a fearsome species that could have wreaked havoc in its prehistoric waters." (P.1) What is your theory on why dinosaurs became extinct? Explain I believe the reason Dinosaurs are extinct because "Dinosaurs ruled the land for million of years." (P. 1)When something grows old, they eventually die. I think that because they had been around so long other things eventually are born or they pop up. I think that a chemical had grown in the air, and lead to dark days, and cold weather, also unhealthy eating and breathing circumstances. When the dinosaurs were living in this world, they had eventually died down enough for the rest of them to be hunted by people.

The article Spinosaurus : A Huge Predatory Dinosaur , Built To Swim, was solid article, with lots of detail. Everyone is different but personally the article didn't draw my attention. Even though the article wasn't my favorite, it was still smooth transitions, and structured good. This article talked about animals that are dead, and that doesn't interest me. The article describes that "Now scientist are discovering a fearsome species that could of wreaked havoc in its prehistoric waters." (P.1) If it was such a big deal, then the topic of discovering more Dinosaurs would have been a bigger deal sometime in history. If Dinosaurs have developed history so much, then why are we just now addressing the new species, that did so much earlier in history? The article very nicely written. The article had some very good qualities as well. For example the facts and supporting details helpless draw attention to the story. Another thing is the article did well was the citation. One more good quality of the text is it used correct indentation, and it also had strong thesis and conclusion sentences. The article was very good in general, but I felt it was lame. The reason I didn't find the article the best, is because the topic wasn't interesting to me. My opinion is; Dinosaurs are extinct, and if they haven't already discovered them they must not be that big of a history developer. To me Dinosaurs were just something that once upon a time lived here, and ruled here. But now it's the humans. Sure the Dinosaurs were once important and very useful, but now there just extremely old, useless, and dead. The structure of the article was very good, but the topic is what brought it down. Spinosaurus are very interesting dinosaurs. For examples most dinosaurs aren't aquatic, but the rare Spinosaurus is. Also as a child we were all told the T-rex was the biggest dinosaur in there kingdom, but actually in length the Spinosaurus is about 9 feet longer than the all powerful T-Rex. This species isn't only rare, but it's different. It states in the text "An unusual fossil who's parts were......." (P.1), proves that it isn't a common thing to find a skeleton like this one, therefor it's different. Even though the topic wasn't my slice of cake, I still learned a lot to add to my previous knowledge!

Definition of havoc- Widespread destruction What are the prehistoric waters? Before knowledge acquired by investigationWhat is the big deal that the Dino is semi-aquatic. Many dinosaurs have bone structured made for land, their for they tend to stay on land, but the Spinosurus is made for water, and there aren't many Dino's that can swim. Definition of AegyptiacusOf/connected with EgyptIs the science Journel creditable?Yes, I looked it upHow could something be across 2 continents? The bones and skeletons can be in various areas, and they could have relocated and left fossils behind, and always moving, they also could be washed away by rain and water.How long is the T-Rex?Depending on the particular one, it's usually like 40 foot long.Paul Serono isa. Paleontologist, at the University Of Chicago and they have a very successful programDefinition of Theropods A carnivorous dinosaurs of a group with any size Dino. (Big or small) What do pressure sensors do?It is a sensor in your nose that helps tell movement Definition of Spindly A rotating disk Definition of marrowThe fat tissue that fills the cavities of bones Definition of Anatomist An expert in anatomy Mesasuar -

A type of dinosaur Buoyancy in water- Means to floatLeft to right in the field- a variety of different people that have different knowledge of things Foreground- the place of a scenery Why did it take so long to begin studies? Because until then it wasn't a major mark or difference in history Definition of sediment encrusted bones Bones that have sediments (sand, silt, clay, erosion, etc. ) stuck on the outsidesHow did Ibraham know about the Spinosaurus when all the evidence had previously been destroyed?Because he knew about them before everything was destroyed so previous knowledge Definition of compelling Drawing Attention to something evoking interestDefinition of hodgepodgeA mixture of two or more substances