Ancient sharks reared young in prehistoric river-delta nursery
Like salmon in reverse, long-snouted Bandringa sharks migrated downstream from freshwater swamps to a tropical coastline to spawn 310 million years ago, leaving behind fossil evidence of one of the earliest known shark nurseries.
That’s the surprising conclusion of University of Michigan paleontologist Lauren Sallan and a University of Chicago colleague, who reanalyzed all known specimens of Bandringa, a bottom-feeding predator that lived in an ancient river delta system that spanned what is today the Upper Midwest.
The new findings, scheduled for online publication Jan. 7 in the Journal of Vertebrate Paleontology, mark the earliest known example of shark migration — a behavior that persists today among species such as tiger sharks in Hawaii.
The Bandringa fossils, as reinterpreted by Sallan and Michael Coates, also reveal the only known example of a freshwater to saltwater shark migration, as well as the earliest example of a shark nursery where fossilized egg cases and juvenile sharks were preserved in the same sediments.
“This pushes migratory behavior in sharks way back,” said Sallan, an assistant professor in the U-M Department of Ecology and Evolutionary Biology. “These sharks bred in the open ocean and spent the rest of their lives in fresh water. No shark alive today is known to do that.”
The long-extinct Bandringa is likely one of the earliest close relatives of modern sharks. It resembled present-day sawfish and paddlefish, with a spoon-billed snout up to half its body length. Juveniles were 4 to 6 inches long and grew into adults of up to 10 feet.
Bandringa was discovered in 1969 and soon became one of the most prized fossils from the well-known Mazon Creek deposits in northern Illinois. Until now, researchers believed that the genus Bandringa contained two species, one that lived in freshwater swamps and rivers and another that lived in the shallow ocean.
— Jim Erickson, Michigan News
Prescription drugs a ‘tipping point’ for dating violence among urban youth
A new University of Michigan Injury Center study recently found a link between misuse of prescription drugs and physical violence among dating partners.
Alcohol and other drugs have been a well-studied health concern among youth with a history of substance use. Previous studies asking youth about daily use over the course of a month show that alcohol and drugs are more likely to be used on days in which violence, both dating and nondating, occurs than on days when there was no violence.
This latest research indicates a connection with misusing prescription sedatives and opioids prior to incidents of dating violence, which many youth or adults may not think of as a risk factor for dating violence.
“Without the alcohol or prescription drugs involved, they simply might walk away from a potentially violent situation,” said Quyen Epstein-Ngo, a fellow at the U-M Injury Center and researcher at the Institute for Research on Women and Gender. “The alcohol and other substance use may be the tipping points.”
The study examined substance use — prescription sedatives and opioids — immediately preceding dating violent conflicts on the day of the conflict among high-risk urban youths.
Both men and women reported that the argument that led to the physical dating violence occurred due to their anger over other things, being in a bad mood, jealousy or as part of an argument about sex.
Given the long-term mental health consequences and potential for physical injury, Epstein-Ngo suggests a need to help teens with healthy responses to conflicts (communication, problem solving) and anger, and to recognize the potential for arguments to escalate when using drugs and alcohol, including prescription drugs.
— Jared Wadley, Michigan News
College football doesn’t always give fans what they want
Unlike college bowl games, regular season football conference schedules pit too many powerhouses against patsies and not enough evenly matched games that fans prefer, says a University of Michigan sports economist.
Stefan Szymanski, professor at the U-M School of Kinesiology, and colleague Jason Winfree of the University of Idaho created nine 13-team mock “ultimate” college football conferences that have equally matched teams.
By running various simulations, they found that aligning conferences based on team quality — the best teams playing the best and the worst playing the worst — made games more exciting and could increase the audience for college football by up to 5 percent.
Some fans may pass up a potentially one-sided game between teams of uneven quality, but may be more likely to watch a game between teams of the same caliber—in hopes of seeing a thrilling, gridiron nail-biter.
“The underlying claim is that the overwhelming fact of college sports, and all major sports, is that people want to see the best play against the best,” Szymanski said. “That is definitely not happening now in college football. This (conference alignment) would produce better matchups and more exciting games.”
According to Szymanski, these results hold true even though there would be fewer rivalry games — although attempts could be made to preserve those rivalries.
Szymanski said that roughly 90 teams have jumped conferences since 2010 — with good reason.
“That’s enormous,” he said. “It’s happening because teams are aligning themselves with better matchups.”
And because teams are seeking bigger audiences and television revenue. But conference-jumping means teams are already moving toward aligning themselves with like-quality teams, he said.
The findings appear in the working paper, “College football scheduling.”
— Laura Bailey, Michigan News
Study tracks changing values in birthplace of Arab Spring
Public attitudes in Tunisia, the birthplace of the Arab Spring, show strong support for secular politics and religious moderation and tolerance, according to a University of Michigan survey.
The findings help to explain the political agreement just reached between Islamists and members of secular groups to form a new Tunisian coalition government.
The survey is part of the Cross-National Analysis of Religious Fundamentalism Study, a systematic study of religious, liberal and other cultural values in seven Middle Eastern countries with Muslim majority populations: Tunisia, Egypt, Iraq, Lebanon, Pakistan, Saudi Arabia and Turkey.
“Religious tolerance is stronger in Tunisia than in the other six countries we’ve studied,” said Mansoor Moaddel, principal investigator of the study.
The results come from face-to-face interviews with a nationally representative sample of approximately 3,000 Tunisian adults.
“But despite public support for the kinds of values that are the basis of American democracy, attitudes towards Americans, while more favorable than in other Middle Eastern countries, have much room for improvement,” said Moaddel, who is affiliated with the University of Michigan Institute for Social Research and the University of Maryland.
Among the key findings of the survey:
• Fully 76 percent believed that the Arab Spring was for democracy and economic prosperity; only 9 percent said it was for the establishment of an Islamic government.
• More than 60 percent said that current political leaders made them upset or angry and fully 86 percent said that government corruption was common.
• A majority of respondents said that life in Tunisia is better now than it was before the revolution.
• More than 60 percent said the most important obligation for Tunisians was to excel in science and technology, compared to 18 percent who identified the top priority as applying sharia law.
— Diane Swanbrow, Michigan News