Monday, January 26, 2015

Does DNA remember?


Can evolution run BACKWARDS? Birds found to regrow bone previously discarded by dinosaurs 230 million years ago

  • Scientists have found that birds regrew a bone known as the 'pisiform'
  • It disappeared from the biology of two-legged dinosaurs when they no longer needed strong wrists
  • However when dinosaurs evolved into birds the bone reappeared
  • The new bone is known as the ulnare and is in the same position
  • It suggests the effects of evolution can be reversible

In 1890 Belgian palaeontologist Louis Dollo postulated that evolution could not run backwards - something widely accepted by the scientific community.

But now a study has claimed that the changes induced by evolution can be reversible, meaning certain animals can return to an earlier biological trait.

The remarkable discovery was made by finding birds had regrown a bone previously discarded by dinosaurs millions of years ago.

They found that 230 million years ago, two-legged dinosaurs no longer required the strong wrists of their four-legged brethren, and thus they became weak.
The number of bones in wrists shrank from 11 to three, with one in particular of interest to disappear being the pisiform.

But according to research by Dr Vargas, the bone reappeared when dinosaurs evolved into birds and took flight.

The new bone, called the ulnare, appears in the same place as the pisiform once did.
The pisiform allowed bird wings to remain rigid on the upstroke. The study found it disappeared in bird-like dinosaurs, but modern birds later evolved to once again use this tiny bone.
'This idea that a bone can disappear and reappear in evolution has been resisted a lot in evolutionary biology,' Dr Vargas previously told Stephanie Pappas at LiveScience.

Scientists don't know how these bones disappeared, though. Professor Vargas said part of the problem is that palaeontologists look at fossils, while biologists focus on embryos.

But his team brought the research together by looking at fossils as well as studying bird anatomy.
The team also traced certain proteins in 3D embryonic skeletons that were linked to the creation of collagen, which makes up connective tissue.

Read more here

Thursday, January 22, 2015

Friday, January 9, 2015

Utah's Dinosaur 'Death Trap' Reveals Trove of Giant Predators

A bed of quicksand entombed six or more Utahraptor dinosaurs—Velociraptor cousins—that may have died while hunting together.

A nine-ton block of sandstone that was pulled from a Utah mountain late last year holds the biggest fossil trove ever found of the giant predatory dinosaur known as Utahraptor. Covered in feathers, with a huge sickle claw on each second toe, Utahraptor looked like a pumped-up version of the Jurassic Park star Velociraptor.

The fossils might help resolve a long-standing debate about whether these predators hunted in groups. In the Jurassic Park films, velociraptors were shown cooperating to chase down prey, an idea based at the time on several predators that had been found alongside an herbivore. The new fossils may help confirm whether the silver screen got it right. (See also: "Jurassic World Dinosaurs Stuck in the 1980s, Experts Grumble.")

Scientists have found the remains of six Utahraptor dinosaurs in the rock so far, and more may be trapped there.

If the dinosaurs died together, they might provide some long-sought evidence of group hunting. The densely packed dinosaurs (in some places, fossils are stacked three feet thick) may have died at different times as they blundered into quicksand, or perhaps they died together in a social supper gone horribly wrong.

The remains were excavated in a massive effort that has spanned more than a decade, led by Utah state paleontologist James Kirkland. (See video above for more on the excavation effort.)

The recent finds include never-before-seen bones that are already changing scientific views of the Utahraptor anatomy.

"We're really going to have a different view of this guy," Kirkland says. Part of the emerging picture is that while young Utahraptor dinosaurs were lightly built and turkey size, Kirkland explains, the adults were heavily muscled, "Arnold Schwarzenegger" versions.

Quicksand Find

Kirkland was tipped off to the site in 2001 by a geology student who had found what first looked like a human arm bone while scouting eastern Utah's early Cretaceous rocks. All the Utahraptor fossils are contained within a large blob of sandstone that appears to have once been what geologists call a "dewatering feature," or in common terms, "quicksand," Kirkland says.

After relocating the site, Kirkland found that the hollow bone was actually part of a dinosaur foot. And there was more.

By chipping off smaller pieces of the block, Kirkland and his team uncovered bones from a 16-foot-long adult Utahraptor, four juveniles, and a baby that would have been only about three feet long from snout to tail.

Other bones at the site belong to a beaked, bipedal herbivore called an iguanodont. The remains of these dinosaurs may have been what attracted the Utahraptor group to the site in the first place.

But these bones are only the bits and pieces that paleontologists have been able to chip off so far. The vast majority of the bones reside in a massive block of sandstone, which gave Kirkland a clue as to why so many raptors became buried in one place.

Dinosaur Death Trap

Kirkland thinks that the Cretaceous drama played out like this: An unwary iguanodont stumbled into the quicksand, bellowing and struggling. If this didn't attract carnivores, then "that nice meaty smell would have," Kirkland says, like flies to flypaper. One Utahraptor after another tried to nab an easy meal and only ended up getting stuck, adding to the deathly aroma.

"We believe it's going to be the first example of dinosaurs trapped in quicksand en masse in the fossil record," Kirkland says.

In order to investigate this idea, though, Kirkland and his team had to get the block out of the field for delicate preparation. "We didn't want to take out a nine-ton block," he says, but "every time we tried to cut in, we kept hitting legs and vertebral columns." (Read about hunting for fossils in "Digging Utah's Dinosaurs" in National Geographic magazine.)

Airlifting the dinosaur-filled rocks with heavy-lift helicopters was too expensive, so Kirkland and his team worked with hands and heavy machinery to get the dinosaurs off the hill and to their temporary home at Salt Lake City's Department of Natural Resources. (See video above.)

Other researchers are paying close attention as the work proceeds. "Any time you find multiple dinosaurs together it's a big deal," says University of Edinburgh paleontologist Stephen Brusatte, "and even more so if they are dromaeosaurs, some of the most iconic but also the rarest dinosaurs in the North American fossil record."

Monday, January 5, 2015

Dinosaurs arrive at Staten Island Zoo

STATEN ISLAND, N.Y. — "Jurassic World," the latest installment of the "Jurassic Park" film franchise, isn't due out until June — but you don't have to wait for that summer blockbuster to score face-time with dinosaurs. 
Eight of the scaly prehistoric creatures are wintering at the Staten Island Zoo, where "Dinosaur Encounters" debuted Thursday, Dec. 18.
A triceratops is among the four species that were welcomed for their four-month stay by about 60 preschoolers who walked over from the Broadway YMCA. The exhibit is now open to the public through April 1 and is free with regular admission to the Zoo.
"They're not real. They're like toys," said one of the adults shepherding the slowly moving wide-eyed tots as they arrived.
Part of Field Station Dinosaurs in Secaucus, the animatronics are part of a 30 life-sized herd of the extinct animals that have been brought to life by scientists, engineers and imaginative artists. Triggered by motion detectors, the eight beasts move heads and tails and grunt and growl hoarsely. 
"The combination of science and imagination, education and fun is something that Field Station shares with the Staten Island Zoo," said Zoo executive director Ken Mitchell.

Read all about it here