Sea snail venom evolution, new research


This video says about itself:

11 January 2012

You’d think a snail wouldn’t be much threat in the sea, but the cone snail proves deadly to unsuspecting fish.

From the University of Michigan in the USA:

Predatory Snails Evolved Diverse Venoms to Subdue a Wide Range of Prey Species

Released: 17-Mar-2015 8:00 AM EDT

ANN ARBOR—A new study by University of Michigan biologists suggests that some predatory marine cone snails evolved a highly diverse set of venoms that enables them to capture and paralyze a broad range of prey species.

When cone snails sink their harpoon-like teeth into their prey, they inject paralyzing venoms made from a potent mix of more than 100 different neurotoxins known as conotoxins.

The genes that provide the recipes for conotoxin cocktails are among the fastest-evolving genes in the animal kingdom, enabling these snails to constantly refine their venoms to more precisely target the neuromuscular systems of their prey.

U-M researchers showed that the mix of neurotoxins in cone-snail venom varies from place to place and is more diverse at locations where the snails have a broad range of prey species. In addition, they concluded that the observed patterns of local conotoxin variation are likely due to natural selection.

That’s a significant finding because it is often difficult for biologists to determine whether place-to-place variations in an organism’s observable traits—the wide range of beak sizes and shapes in the Galapagos Islands finches studied by Charles Darwin, for example—are the result of evolution by natural selection or some other factor, such as the reproductive isolation of a population of animals or plants.

In addition, the U-M researchers were able to directly target the genes responsible for the observed conotoxin patterns. A paper summarizing the work is scheduled for online publication in the journal Proceedings of the Royal Society B on March 18.

“The differences in venom composition that we observed correspond to differences in prey, and a higher diversity of venom is used to capture more prey species,” said first author Dan Chang, formerly a doctoral student in the U-M Department of Ecology and Evolutionary Biology and now a postdoctoral researcher at the University of California, Santa Cruz.

“Our results suggest that prey diversity affects the evolution of predation genes and imply that these predators develop a more diverse venom repertoire in order to effectively subdue a broader range of prey species,” Chang said.

The study involved a common species of tropical, worm-eating cone snail, Conus ebraeus, collected at locations in Hawaii, Guam and American Samoa. These snails are about an inch long and are commonly known as Hebrew cone snails. Their shells are white with black rectangular markings that form a distinctive checkerboard pattern.

The researchers characterized the patterns of genetic variation in five toxin genes in C. ebraeus snails from the three locations. They also collected fecal samples from the snails to determine the types of worms they ate.

“We demonstrated that venom genes used for predation are highly affected by local variation in prey diversity and geographic heterogeneity in prey compositions,” Chang said. “Not all conotoxin genes are affected in the same way though, which implies that these genes may have distinct functional roles and evolutionary pathways.”

The other U-M authors are Thomas Duda and Amy Olenzek. The study was funded by a National Science Foundation grant to Duda, who is an associate professor in the Department of Ecology and Evolutionary Biology and an associate curator at the U-M Museum of Zoology.

Dan Chang
Thomas Duda

Long-tailed duck, new species for Dearborn, USA


This is a long-tailed duck video.

From the blog of the Rouge River Bird Observatory at the University of Michigan-Dearborn in the USA:

Monday, March 2, 2015

Dearborn adds another new species!

On 1 March 2015, Larry Urbanski found a Long-tailed Duck (Clangula hyemalis) in the Rouge River near the Ford Rouge Plant. There is a photo attached to his eBird checklist (sign in may be required for one or both links) and the bird appears to be a male.

Mike O’Leary and I attempted to locate the bird this morning, and found a Long-tailed Duck that appears to be a female, or at least doesn’t look like the bird found yesterday. …

Long-tailed Duck is the 260th species on the Dearborn list.

Most of the Rouge River is still frozen solid. The areas in the Ford Rouge boat slip and adjacent waters stay open all year. Other waterfowl present included a couple hundred Common Mergansers, at least 24 Red-breasted Mergansers, Canvasbacks, a few Ruddy Ducks, Common Goldeneye, Redheads, and Greater Scaup. There were at least 20 Great Black-backed Gulls — a species not recorded in Dearborn until 1987. Ten sort of miserable looking Great Blue Herons hugged the shoreline, as did 10 Black-crowned Night-herons. There is a small pond inside the plant next to the river that accepts warm-water discharge from one of the steel mill facilities, and a bunch of night-herons have wintered there for years.

Many thanks to Larry Urbanski for this great find.

Posted by Julie Craves.

Mastodon discovery in Michigan backyard


This video from the USA says about itself:

Bachelor party makes rare mastodon fossil discovery

13 June 2014

People at a bachelor party on a lake shore in New Mexico stumbled upon a rare fossil: the skull of a mastodon. It is considered to be an ancient elephant, complete with tusks and teeth. Scott Pelley reports.

From Popular Science in the USA today:

These Guys Found The Remains Of A 14,000-Year-Old Butchered Mastodon In Their Backyard

Mastodon burgers anyone?

By Mary Beth Griggs

Posted 39 minutes ago

It isn’t every day that you find bones in your backyard, much less a 4-foot long rib bone sticking out of the earth. After that initial, massive find, neighbors Daniel LaPoint Jr. and Eric Witzke kept digging, eventually unearthing 42 massive bones from a property in Bellevue Township, Michigan last November. At first, they thought the bones might have belonged to a dinosaur, but it turns out that the remains were far younger.

“Preliminary examination indicates that the animal may have been butchered by humans,” Daniel Fisher, director of the University of Michigan Museum of Paleontology told the Lansing State Journal. Fisher examined the bones when LaPoint and Witzke contacted the museum, and eventually determined that in addition to being butchered by humans, the bones belonged to a 37-year-old mastodon (a relative of elephants and mammoths) that lived roughly 14,000 years ago.

The Journal reports that while unusual, finding the bones of mastodons isn’t totally unheard of in Michigan; about 330 sites have been confirmed around the state, two in the past year.

Fossils found on private land in the United States belong to the landowner, not the government, so the fossil finders LaPoint and Witzke are keeping a few of the bones as the coolest mementoes ever and donating the rest to the University of Michigan Museum of Paleontology. But before they travelled to the museum, the pair took the bones to a local school, where kids got to experience the fossils up close and personal.

“All the kids got to pick them up and hold them. Some kids, it was life-changing for them. To change one kid’s life because they got to touch it, I think, is an incredible opportunity.” LaPoint told the Lansing State Journal.

See also here.