From the oldest dinosaur to the odd fish eating Suchomimus by Steve Brusatte
A portrait of Paul Sereno
Sereno is the master of discovery
by Steve Brusatte
There are basically three types of paleontologists. Many paleontologists simply trek out into the field with the intention of excavating museum quality specimens, such as the great Barnum Brown. Some fossil hunters search countless formations to gather information on how dinosaurs and other prehistoric animals lived, such as John Horner and his search for baby dinosaurs. Still others go into the field with the hope of finding new species. Dr. Paul C. Sereno is arguably the most successful of this breed of paleontologists.
You definitely will recognize the name Paul Sereno if you are a die hard paleontology buff. But, even if you are just a low key dinosaur fan, Sereno probably seems very familiar. If you live in the United States, you may remember that the Associated Press made a large story of his Suchomimus discovery. This find, announced in November, turned into one of the most media friendly dino discoveries of all time. Regardless of the media blitz, Suchomimus was a monumental find, and extremely important to dinosaur paleontology. But, Suchomimus is not Sereno\'s only find. Not even close.
Sereno\'s life in paleontology has taken many odd twists and turns. As a youth, he was the rebellious child from an academically elite family (he has five siblings, who all also hold Ph.D.s). He became so much of a trouble case that he almost failed sixth grade. But, he managed to get through grade school, and then high school, and he then enrolled in Northern Illinois University. Not knowing where he wanted to go in life, Sereno looked for a profession. He found it in paleontology. While visiting his brother Martin, he was given a tour of the American Museum of Natural History in New York City. He then knew that paleontology was for him.
Knowing that he could combine art, travel, biology, geology, and adventure, Sereno applied for Columbia University after graduating from Northern. Just a few years later the child who once almost failed sixth grade walked out of the university with a Doctorate, and a fresh mind ready to explore the fossils of the world. He was soon hired as a professor by the University of Chicago, and that began his brilliant career in paleontology.
In 1988 Sereno led his first expedition, which turned out to be a huge success. He led a team to the Andes in Argentina, and, during the third week, made an astounding find. While exploring an outcrop he noticed what appeared to be a neck vertebrate. He looked closer and realized that that vertebrate led to the first skull of Herrerasaurus ever discovered. Sereno and his team named this dinosaur after Victorino Herrera, who first led paleontologists to the site of the find.
In 1991 Sereno led yet another expedition to Argentina. During this trip another outstanding find was made. Ricardo Martinez, a member of the crew, stumbled across an odd looking skull. The skull turned out to be that of a theropod early on the dinosaur family tree. Sereno named it Eoraptor, or dawn raptor. The raptor measured only three feet long, and was approximately 228 million years old. Sereno, like Horner, used this find to make a hypothesis. Eoraptor and Herrerasaurus showed specializations that would have placed them with other theropods, Sereno stated. Therefore, they were not as primitive as once thought, meaning, according to Sereno, that the dinosaurs radiated earlier than previously expected.
After Argentina Sereno shifted his work to Africa, to look for the first signs of Cretaceous dinosaurs. His work started off quickly with the discovery of Afrovenator abakensis (hunter from Abaka, Africa). This 27 foot long predator was discovered in a bed of 130 million year old rocks in 1993. This terrible lizard had a three-fingered hand, a sickle like claw, and two inch long bladelike teeth. Most importantly, though, were the insights that Afrovenator gave into the disassembling and splitting of Pangea. Before Sereno\'s discovery, many thought that Pangea had split into two before the time of Afrovenator, but the dinosaur\'s closest relative is the Allosaurus, found in North America.
Instead of close relations to dinosaurs in South America (which was believed to be connected to Africa after Pangea split), Afrovenator was closely related to a dinosaur that was supposed to be thousands of miles and a sea length away. To Sereno, this makes him believe that Pangea must have lasted much longer than previously thought (previous thoughts implied that Pangea separated 150 mya.)
In 1995 Sereno led another expedition to Africa. From 90 million year old rocks in Morocco the team unearthed the first skull of Carcharodontosaurus saharicus and the 25 foot long predator Deltadromeus.
Deltadromeus agilis (agile delta runner) was a very rare and important find. This fleet footed carnivore was actually discovered by team member Gabrielle Lyon, who is now Sereno\'s wife. It was later identified as a new species in the journal Science. The skull of Carcharodontosaurus (shark toothed reptile from the Sahara) was an astounding drawer of news. The reason: Carcharodontosaurus was a 45 foot long predator, which was 5 feet longer than T. rex, even though its brain was only half of the size of the tyrant lizard king. This dinosaur probably preyed on sauropods, Sereno said.
All of these finds were outstanding and crucial to science, but none drew the media attention of the now famed Suchomimus. This find was so well received that it made the front page of the Chicago Tribune, was mentioned in Time Magazine, and drew a National Geographic television special.
In 1997 Sereno led an expedition to the war torn country of Niger. Risking the possibility of death, the team evaded troops and the constant heat to discover one of the most important paleontological specimens of the decade.
The story of the find is not one of complex planning and digging, but of a simple discovery. It was so simple that team member David Varricchio just spotted a large, odd claw eroding from the hot desert sand. That claw led to over 400 pieces of bone, buried just inches below the surface.
After the digging was through Sereno took the specimen to his lab and made many interesting conclusions. The dinosaur he named Suchomimus tenereneis (crocodile mimic from the Tenere) was a 36 foot long predator that would have been twelve feet tall at the hips. Sereno placed it in the Spinosaurid family, making it the most complete of these odd sailed dinosaurs ever discovered.
The most interesting part of Suchomimus was definitely its skull. Its four foot long skull came to an end at a narrow snout with large teeth near the end. These 100 subconical teeth were protected by a rosette, or a chin like protector. These odd teeth were not similar to most carnivore teeth, either. Unlike the teeth of Tyrannosaurus or Allosaurus, the teeth of Suchomimus were not like steak knives, but more like hooks. These features are similar to a specialized fish eater, Sereno pointed out. \"It was a dinosaur trying hard to be a crocodile,\" Sereno stated.
The dinosaur had foot long thumb claws, powerfully built forearms, which were used to snare prey, and a thin bony sail that was probably used for display purposes only.
Suchomimus would have lived in a lush, swampy environment 100 million years ago. This area was filled with fish, and would have been an ideal habitat for this odd crocodile mimic.
\"It was the dominant predator of its time,\" Sereno stated
Dr. Thomas Holtz, Jr. of the University of Maryland points out the importance of some of Suchomimus\' features. The evolution of a fish eating diet, he stated in his Science article that was printed adjacent to Sereno\'s description of the species, may help explain just why so many predators could fit into one area.
Holtz pointed out that in today\'s world there is usually only one main predator in an ecosystem. But, Suchomimus would have had to share the land with Carcharodontosaurus and Deltadromeus. If it was specialized to eat fish, and then the other specialized to eat meat, many large predators could fit into the very same area, Holtz pointed out.
Suchomimus was closely related to Baryonyx, an English Spinosaur, which suggests to Sereno that the spinosaur ancestor crossed the broad Tethyan Seaway that separated the north and south landmasses. He suggests that a land bridge probably linked these two continents.
Suchomimus was definitely an important find. Evolution gave it the tools to eat fish, which was a food source beyond the reach of other predators. This may lead to new insights in just how dinosaurs were able to rule the earth for such an extremely long period of time, Holtz points out.
Through countless field work and lab studying, Paul Sereno of the University of Chicago has become one of the most successful dinosaur hunters. Once a troubled child, this man has risen to become one of the most well known paleontologists today.
But, his fame is well worth it! Without Sereno we would not have the knowledge of the youngest dinosaurs, the radiation of dinosaurs, and now the evolution of Spinosaurids. And, without Sereno, we would not have Herrerasaurus, Eoraptor, Carcharodontosaurus, Afrovenator, Deltadromeus, and now, Suchomimus.