Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Prehistoric tusks point to earliest fossil evidence of differences between sexes

24.01.2003


Image: R. Reisz


Findings point to complex social behaviour

The large tusks of an animal that roamed Earth before the dinosaurs may provide the earliest evidence yet of male-female distinctions in land animals that existed millions of years ago, say U of T scientists.

Robert Reisz, a biology professor at the University of Toronto at Mississauga, and his team have found convincing evidence of sexual dimorphism - different physical traits between the sexes of the same species - in their study of fossils from between 252 to 260 million years ago. They believe that the male Diictodon, a herbivorous barrel-shaped creature, had two large tusks extending down from the upper jaw. The tusks, Reisz says, were used as weapons, possibly for ritualistic or physical combat.



"Our findings give very clear evidence of complex social behaviour," Reisz says. "To see this kind of behaviour [physical combat] early in the history of the group that eventually gave rise to mammals is really quite startling."

Reisz’s study, which is featured on the cover of the January issue of the Proceedings of the Royal Society of London B, was based on detailed studies of nearly a hundred skeletons unearthed in South Africa over the last two decades.

Diictodon appeared during the Late Permian Period of the Paleozoic Era, at least 30 million years before dinosaurs existed. It was part of a group of animals described as mammal-like reptiles and was an evolutionary relative of the animals that evolved into mammals. Diictodon, which was covered in scales and measured about one metre in length, was a burrowing herbivore with a beaked skull and short tail.

In its investigation, the team was able to rule out other uses for the tusks, Reisz says. The tusks were not used for feeding because the females did not have them nor were they used for digging because the ends did not show signs of wear. It appears the tusks became longer, wider and thicker as the animals aged and extended well below the jaw line; those lost, possibly in combat, were never replaced, Reisz says. "All these factors are very strong indicators of armament."

Reisz says these findings go beyond the standard skeletal descriptions that accompany research on fossils. "This is a wonderful opportunity to study the biology of animals that lived so long ago. Rather than just simply looking at them and describing them, we can do more with their lifestyle, with their feeding habits, and with their general biology than just looking at their skeletons would suggest."

Along with Reisz, the study involved Corwin Sullivan, now a graduate student at Harvard University, and Dr. Roger M.H. Smith of the South African Museum in Cape Town, South Africa. The research was funded by the Natural Sciences and Engineering Council of Canada and by the American Museum of Natural History.

Nicolle Wahl is a news services officer with the department of public affairs.

CONTACT:

U of T Public Affairs, ph: (416) 978-6974; email: nicolle.wahl@utoronto.ca

Nicolle Wahl | EurekAlert!
Further information:
http://www.newsandevents.utoronto.ca/bin4/030123b.asp

More articles from Life Sciences:

nachricht New switch decides between genome repair and death of cells
27.09.2016 | University of Cologne - Universität zu Köln

nachricht A blue stoplight to prevent runaway photosynthesis
27.09.2016 | National Institute for Basic Biology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

Laser use for neurosurgery and biofabrication - LaserForum 2016 focuses on medical technology

27.09.2016 | Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

 
Latest News

New imaging technique in Alzheimer’s disease - opens up possibilities for new drug development

28.09.2016 | Medical Engineering

Innovate coating extends the life of materials for industrial use

28.09.2016 | Materials Sciences

Blockchain Set to Transform the Financial Services Market

28.09.2016 | Business and Finance

VideoLinks
B2B-VideoLinks
More VideoLinks >>>