before it's in the papers"
June 04, 2013
TO THE WORLD SCIENCE HOME PAGE
Courtesy University of Bonn
and World Science staff
A species of dinosaurs
known as the biggest land animals that ever lived, had some miniature cousins, a study has found. According
to researchers, the little reptiles weighed about one fiftieth as much as their
closest relatives, the well-known brachiosaurs’ long-necked, massive plant-eaters.
It’s not the first scientific sensation surrounding the discovery of a miniature version of a familiar animal. And the last time such a
sensation arose, it didn’t turn out very well.
|Newly unveiled models of a group of Europasaurus on display at the Dinopark MÃ¼nchehagen.
(Courtesy Dinopark MÃ¼nchehagen.)
Researchers in 2004 reported discovering fossils from a species of miniature humans on the Indonesian island of Flores. A growing number of scientists now
dispute the finding, saying the
bones probably came from an ordinary person with a disease.
The researchers in the dinosaur study say they’re untroubled by that ongoing
When the little reptilian fossils turned up at the edge of Germany’s Harz Mountains in 1998, researchers assumed they were the remains of young dinosaurs. But palaeontologist Martin Sander of the University of Bonn, Germany, and colleagues argue in the
new study that they were probably adults. They based this conclusion on the microscopic structure of the bones.
Their analysis appears in the June 8 issue of the research journal Nature.
Dinosaur bones have “growth marks,” not unlike the annual rings on trees, Sanders explained. When the
reptiles were young the growth marks are far apart, because the animal
was growing fast; but the marks lie close together for adult dinosaurs,
which had already reached full size.
“It is precisely these tightly compressed marks that we have discovered just beneath the surface of the fossil’s
bones,” said Sander, a specialist in the micro-structure of dinosaur skeletons.
“The dinosaurs must have been fully grown when they died.”
These “dwarf” dinosaurs were slightly longer and heavier than a car, Sander said.
“They stopped growing when they reached 6 metres [20 feet] in length and a ton in body mass,” he estimated.
Their brachiosaur cousins, by contrast, were up to 45 metres (148 feet) long and weighed
80 tons, as much as a small town of over 1,000 inhabitants.
The 150 million-year-old fossil bones were seen as a rarity even before
the new research. During the dinosaurs’ time, large parts of Germany were underwater, with only a few islands sticking out. Dinosaurs are land animals, so fossil dinosaurs are rare in
This island situation may well explain why the “pygmy dinosaurs” evolved, Sanders and colleagues say.
When the sea level rose, flooding more and more land, food might have become scarce. “The result was enormous pressure to evolve: smaller animals which needed less food had better chances of survival,” said Nils KnÃ¶tschke of the Dinopark in MÃ¼nchehagen, Germany, a member of the research team.
“Shrinkage like this due to a reduction in the food available can take place extremely rapidly, sometimes within 10 or 20 generations,” Sander added. In Britain, he
noted, deer were introduced to the Shetlands which quickly evolved into a dwarf species of deer. And
on Flores in Indonesia, there used to be a miniature elephant hardly bigger than a St.
This all fits in with the discovery of
“Flores Man,” said the
researchers, who voiced no concerns that skepticism over that case would
spill over into their work.
OctÃ¡vio Mateus of the Universidade Nova de Lisboa, a member of the
research team, wrote in an email that his group has stronger arguments
than those who proposed the “Flores Man” species, because of the “large sampling of bones with unique adult micro-structure features.”
“Flores Man” was slightly over half the height of a regular adult male, whereas these dinosaurs would be less than one-seventh the
length of their giant counterparts.
The researchers gave the diminutive dinosaurs the scientific name Europasaurus holgeri.
The moniker honors Holger Luedtke, a hobbyist first found the fossils in 1998 in a quarry near Oker, on the northern edge of the Harz Mountains.
* * *
Send us a comment
on this story, or send
it to a friend
Meeting online may lead to happier marriages
Poverty reduction, environmental safeguards go hand in hand: UN report
Was blackmail essential for marriage to evolve?
Pluto has even colder “twin” of similar size, studies find
Could simple anger have taught people to cooperate?
Different cultures’ music matches their speech styles, study finds
Frog said to describe its home through song
Even rats will lend a helping paw: study
Drug may undo aging-associated brain changes in animals