Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Polygamy, Paternal Care in Birds Linked to Dinosaur Ancestors

22.12.2008
Sure, they’re polygamous, but male emus and several other ground-dwelling birds also are devoted dads, serving as the sole incubators and caregivers to oversized broods from multiple mothers. It is rare behavior, but research described in the Dec. 19 Science found that it runs in this avian family, all the way back to its dinosaur ancestors.

Scientists had long wondered about the origins of polygamy and paternal care patterns among modern-day Paleognathes -- an ancient avian lineage that branched off soon after birds evolved from dinosaurs and includes ostriches, emus and tinamous.

No such reproductive behavior exists among the vast majority of other vertebrates. Males contribute to parental care in less than 5 percent of mammal and non-avian reptile species, and while more than 90 percent of bird species co-parent to some degree, it is only among the Paleognathes that both polygamy and paternal care rule.

Now, in a groundbreaking paper (“Avian Paternal Care Had Dinosaur Origin”), paleobiologist Gregory M. Erickson of The Florida State University and researchers from three other institutions connect the evolutionary dots linking the polygamous, paternal reproductive patterns of extant (living) birds to the behavior of their extinct dinosaur kin.

“In those cases where adult dinosaurs have been found on top of nests, we found that the volume or mass of the egg clutch (total number of eggs in the nest) is very large relative to the size of the nesting animals,” Erickson said. “This suggests multiple females contributed the eggs and the male guarded them. Notably, the ratio of egg volumes to the nesting animal’s size is consistent with those in living birds where the male is the sole or primary nest attendant.”

The researchers now had their link from the theropod dinosaurs (omnivores and carnivores that walked on two hind legs with bird-like feet) to the polygamy and nesting scenarios exhibited by their avian descendants, according to David Varricchio of Montana State, the study’s principal investigator.

But to test the theory, Varricchio needed to determine the sex of the brooding dinosaurs whose bones have been found atop those communal nests.

For that, he turned to Erickson at Florida State, a renowned expert in dinosaur paleobiology.

Erickson examined the bone microstructure of tibiae (shin bones), femora (thigh bones) and metatarsus (ankle bones) from oviraptorids and deinonychosaurs (Jurrasic Park “raptors”) -- small theropod dinosaurs whose adult skeletons have been repeatedly discovered in brooding postures atop nests containing dozens of large eggs.

The key was what he didn’t find in the bones: They showed no signs whatsoever of the maternal and reproductively associated microscopic features common to living non-Paleognath bird groups, extinct non-avian dinosaurs or living reptiles.

“I found no evidence of medullary bone (the extra bone laid down by breeding female birds and dinosaurs to make eggs) or extensive bone resorbtion (the means by which female reptiles such as crocodiles acquire mineral salts to make eggs),” Erickson said. “This is consistent with the brooding dinosaurs being males.”

Thus, the researchers had confirmation that the dinosaurs found in nests with large egg clutches were polygamistic males and the source of the peculiar avian behavior.

Moreover, those brooding dinosaurs were fathers -- and today’s emus, rheas and tinamous owe their paternal care model to them.

Co-authors of “Avian Paternal Care Had Dinosaur Origin” -- accessible via the journal Science Web site at www.sciencemag.org/current.dtl -- are Florida State’s Erickson, associate professor of anatomy and vertebrate paleobiology in the Department of Biological Science; Varricchio, Frankie D. Johnson and John J. Borkowski of Montana State University; Jason R. Moore of Texas A&M University; and Mark A. Norell of New York City’s American Museum of Natural History.

Gregory Erickson | Newswise Science News
Further information:
http://www.bio.fsu.edu
http://www.sciencemag.org/current.dtl

Further reports about: Birds Erickson Polygamy Reptile ancestors avian brooding dinosaur emus non-avian reptile species ostriches paternal tinamous

More articles from Life Sciences:

nachricht The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences

nachricht Transforming plant cells from generalists to specialists
07.12.2016 | Duke University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>