Human hair, bird feathers came from reptile scales

By Ben PankoJun. 24, 2016 , 2:45 PM

Hair, scales, and feathers seem to have very little in common. But these structures appear to have evolved from a single ancestor—a reptile that lived 300 million years ago—according to new research.

The study could end a long and contentious debate in evolutionary biology, says Leopold Eckhart, a dermatology researcher at the Medical University of Vienna, who was not involved in the work. "This really closes some important questions."

Hair in mammals and feathers in birds have long been known to develop from placodes—patches of thickened skin in embryos that are created by special cells known as columnar cells. These patches had not been seen in reptile embryos, leading scientists to believe that scales were unrelated to hair and feathers. Because birds and mammals evolved from separate lineages, scientists had two hypotheses: Placodes evolved two separate yet identical times in birds and mammals, respectively, or reptiles lost them over time, whereas birds and mammals didn't.

"People were imagining very complex hypotheses to explain the absence of placodes in reptiles," says University of Geneva geneticist Michel Milinkovitch in Switzerland.

Milinkovitch unwittingly waded in to this decades-long debate after seeing a rare, scaleless reptile—an Australian bearded dragon—at a pet market. After purchasing the animal, he investigated its DNA and found that a mutation of the gene ectodysplasin-A(EDA) led to the scalelessness. Mutations on this gene are also known to cause baldness, along with deformed teeth and nails, in mice and humans. This discovery led Milinkovitch and his colleague, University of Helsinki biologist Nicolas Di-Poï, to wonder whether there might be a relation between hair and scale development.

To find out, the team looked at the embryos of bearded dragons, Nile crocodiles, and corn snakes. In contrast with previous research, the team found that the reptiles in fact formed placodes, as it reports today in Science Advances.

Read on ...

'Fluffy and feathery' dinosaurs were widespread

25 July 2014 Last updated at 02:19

By Pallab Ghosh

Science correspondent, BBC News

All dinosaurs were covered with feathers or had the potential to grow feathers, a study suggests.

The discovery of 150-million-year-old fossils in Siberia indicates that feathers were much more widespread among dinosaurs than previously thought.

The find "has completely changed our vision of dinosaurs", the lead researcher told BBC News.

The details have been published in the journal Science.

The creature, called Kulindadromeus zabaikalicus, was about 1m long, with a short snout, long hind legs, short arms, and five strong fingers.

Its teeth show clear adaptations for chewing plants.

Until now, fossilised evidence of feathery dinosaurs has come from China and from a meat eating group called theropods.

The latest discovery, in Russia, is from a completely separate group of plant-eating dinosaurs called ornithischians - which account for half of all dinosaurs.

Continued

Feathered Dinosaurs Drive Creationists Crazy

The dinosaurs of our childhood aren’t around anymore. The sluggish, swamp-bound pea-brains that haunted museum halls and trundled through picture books have been eviscerated by agile, hot-blooded, and, often, feathery dinosaurs that more accurately reflect what Tyrannosaurus rex and kin were actually like. What’s more, thanks to a heap of lovely fossils, we now know that even the most fearsome of the tyrant dinosaurs were closely related to the avian dinosaurs—the birds—that flit around our backyards today.

Not everyone is pleased with the dramatic dinosaur makeover. In “How Science Ruined Everything,” io9’s Esther Inglis-Arkell said, “Dinosaurs used to be cool, feathers came in, and now it’s like, they’re going to ruffle their plumage when they come after me, and that is not scary.” It’s not surprising that the new imagery of enfluffed dinosaurs makesVelociraptor and company seem more like chickenosaurs than the monsters we grew up with. I used to hate fluffy dinosaurs, too. When feathery dinosaurs started to appear in museum shops and poorly-rendered fuzzballs strutted through basic-cable documentaries, I mourned the loss of the reptilian monsters I once knew. But when I dug into why dinosaur depictions have changed so radically, I came away with a new appreciation of dinosaur feathers.

Paleontologists have uncovered scores of fluffy, fuzzy, bristly, and otherwise spectacularly-adorned dinosaur species throughout the group’s family tree. Feathers weren’t meant for flight from the start; at first they were adaptations for insulation and display—for showing off. By comparing the microscopic features of dinosaur feathers with those of modern birds, paleontologists are answering one of the most perplexing dinosaur mysteries: What color were they? (Some were iridescent blue; some were black and white like a magpie; and some had rust-colored stripes along their tails.) We can finally start to explore the beauty of the dinosaur palette, something I was told as child would be totally impossible. I’ll trade evolutionary secrets for slightly silly dinosaurs any day.

Continued:  http://www.slate.com/articles/health_and_science/science/2012/09/creationists_and_dinosaurs_answers_in_genesis_teams_with_dissident_scientists_to_deny_feathered_dino_fossil_record.single.html

Biological Mechanism for Growing Massive Animal Weapons, Ornaments Discovered

ScienceDaily (July 26, 2012) — In the animal kingdom, huge weapons such as elk antlers or ornaments like peacock feathers are sexy. Their extreme size attracts potential mates and warns away lesser rivals.

Now researchers led by scientists at the University of Montana and Washington State University have discovered a developmental mechanism they think may be responsible for the excessive growth of threatening horns or come-hither tail feathers. Published in the July 26 online edition of Science, the research reveals a mechanism to explain both the size of these traits, and the incredible variation among males of the same species -- why some beetles, for instance, grow massive horns while their fellows grow nothing but nubbins.

"Our research explains how these enormous traits get to be so enormous," said Doug Emlen, a professor and evolutionary biologist in UM's Division of Biological Sciences. "People have known for 100 years that the best males produce the biggest structures, but nobody has really understood how. Our work looks under the hood to explain why so many sexually selected structures get so massive."

Continued:  http://www.sciencedaily.com/releases/2012/07/120726142202.htm

Disappointment after rare feathers stolen

A volunteer at the small museum where two valuable rare feathers from an extinct native bird were stolen is not hopeful they will be returned.

The 123-year-old tail feathers were taken from one of two stuffed huia birds that were kept in a secure glass case at the Gallery of History in Dannevirke.

Dannevirke police are investigating and are appealing to the public for any information about the theft, which is believed to have occurred on either Wednesday or Friday last week.

Pat Mills, who is one of a number of volunteers at the museum, told NZ Newswire she doesn't hold much hope the feathers will be returned.

"It's going to be very difficult to find out who took them."

She said there will be an amnesty, so if the person who took them felt that they had done the wrong thing, they could slip them under the gallery door and nothing more would be said.

"But I don't know if that will happen," Mrs Mills said.

The museum has been looking after the two huia for a local family for 25 years.

Mrs Mills says the huia were shot in the nearby Pohangina Valley in 1889 for a wedding present.

The museum is disappointed the feathers have been stolen and Mrs Mills says the theft has deprived future generations the chance to see what an authentic huia looked like.

The last live huia was seen in the Tararua Ranges in 1907.

A feather, similar to the ones stolen, was sold at auction in Auckland in 2010 for $8400.

It was said at the time to be a world record price for a bird feather.

http://news.msn.co.nz/nationalnews/8442150/rare-huia-feathers-stolen-from-museum