Defining what’s unique about these ‘fearfully great lizards’ gets harder with new finds
BY CAROLYN GRAMLING 4:00PM, FEBRUARY 21, 2018
“There’s a very faint dimple here,” Sterling Nesbitt says, holding up a palm-sized fossil to the light. The fossil, a pelvic bone, belonged to a creature called Teleocrater rhadinus. The slender, 2-meter-long reptile ran on all fours and lived 245 million years ago, about 10 million to 15 million years before scientists think dinosaurs first appeared.
Nesbitt, a paleontologist at Virginia Tech in Blacksburg, tilts the bone toward the overhead light, illuminating a small depression in the fossil. The dent, about the size of a thumbprint, marks the place where the leg bone fit into the pelvis. In a true dinosaur, there would be a complete hole there in the hip socket, not just a depression. The dimple is like a waving red flag: Nope, not a dinosaur.
The hole in the hip socket probably helped dinosaurs position their legs underneath their bodies, rather than splayed to the sides like a crocodile’s legs. Until recently, that hole was among a handful of telltale features paleontologists used to identify whether they had their hands on an actual dinosaur specimen.
Another no-fail sign was a particular depression at the top of the skull. Until Teleocrater mucked things up. The creature predated the dinosaurs, yet it had the dinosaur skull depression.
The depression in Teleocrater’s hip bone (bottom half) marks where the leg bone fit into the pelvis. Dinosaurs have a complete hole in that part of the hip socket.
<img src=”https://www.sciencenews.org/sites/default/files/2018/02/030318_CG_dino_inline1_370.jpg” alt=”” class=”caption” style=”float: right; width: 370px; height: 238px;” title=”The depression in <em>Teleocrater</em>’s hip bone (bottom half) marks where the leg bone fit into the pelvis. Dinosaurs have a complete hole in that part of the hip socket. ~~ S.J. Nesbitt” />
The once-lengthy list of “definitely a dinosaur” features had already been dwindling over the past few decades thanks to new discoveries of close dino relatives such as Teleocrater. With an April 2017 report of Teleocrater’s skull depression (SN Online: 4/17/17), yet another feature was knocked off the list.
Today, just one feature is unique to Dinosauria, the great and diverse group of animals that inhabited Earth for about 165 million years, until some combination of cataclysmic asteroid and volcanic eruptions wiped out all dinosaurs except the birds.
“I often get asked ‘what defines a dinosaur,’ ” says Randall Irmis, a paleontologist at the Natural History Museum of Utah in Salt Lake City. Ten to 15 years ago, scientists would list perhaps half a dozen features, he says. “The only one to still talk about is having a complete hole in the hip socket.”
The abundance of recent discoveries of dinosauromorphs, a group that includes the
dinosaur-like creatures that lived right before and alongside early dinosaurs, does more than call diagnostic features into question. It is shaking up long-standing ideas about the dinosaur family tree.
To Nesbitt, all this upheaval has placed an even more sacred cow on the chopping block: the uniqueness of the dinosaur.
“What is a dinosaur?” Nesbitt says. “It’s essentially arbitrary.”
Today, only one fossil feature can be attributed solely to members of Dinosauria: a complete hole in the hip socket.
Several others, including the four below, are no longer surefire dinosaur signs:
Sources: S.J. Nesbitt et al/Nature 2017; S.L. Brusatte et al/Earth-Science Reviews 2010
In 1841, British paleontologist Sir Richard Owen coined the term “dinosaur.” Owen was contemplating the fossil remains of three giant creatures — a carnivore named Megalosaurus, the plant-eating Iguanodon and the heavily armored Hylaeosaurus. These animals shared several important features with one another but not other animals, he determined. (In particular, he noted, the creatures’ giant legs were upright and tucked beneath their bodies, and each of the animals had five vertebrae fused together and welded to the pelvis.)
Owen decided the animals should be biologically classified together as their own group, or taxon. He named the group “Dinosauria” for “fearfully great lizards.”
In Owen’s day, it was a bit easier to spot similarities between fossils, says paleontologist Stephen Brusatte of the University of Edinburgh. “Back then, there were so few dinosaurs. But the more fossils you find, the patterns become more complicated,” he says. “With every new discovery, you get a different view of what features define a dinosaur. It’s nowhere near as clear-cut as it used to be.”
<img src=”https://www.sciencenews.org/sites/default/files/2018/02/030318_CG_dino_icon4_100.jpg” alt=”” style=”width: 100px; height: 63px; float: left;” />
The largest extinction of species on Earth, the “Great Dying,” happened about 252 million years ago at the end of the Permian Period (SN: 9/19/15, p. 10). About 96 percent of marine species and 70 percent of land species succumbed.
In the period that followed, the Triassic, spanning 252 million to 201 million years ago, new reptilian species arose and flourished. This was the time of the dinosauromorphs, crocodylians (the ancestors of crocodiles) and, of course, the dinosaurs themselves. No one knows exactly when dinosaurs arose, although it was probably around 230 million years ago.
For tens of millions of years, the dinosaurs lived alongside numerous other reptile lineages. But at the end of the Triassic, dramatic climate change played a role in another mass extinction. Dinosaurs somehow survived and went on to dominate the planet during the Jurassic Period.
Magic Milk Experiment:
How it Works:
Milk has fat in it and the food coloring floats on top of the fat. The fat is all connected with bonds. Think of it like the little pieces of fat all holding hands with each other. Dish soaps are used on greasy or oily dishes because it breaks the bonds in fats allowing them to separate. When you add the dish soap to the milk, the fat separates and moves making your magical milk art!
Does the temperature of the milk have any effect?
Try whole milk and skim milk.
Sprinkle pepper on the milk before you add the soap, what happens to the pepper?
It was the guano that gave the birds away
BY KATY DAIGLE 6:26PM, MARCH 2, 2018
On an expedition to an icy island chain off the Antarctic Peninsula’s northern tip, researchers discovered a massive supercolony of more than 1.5 million Adélie penguins, according to a study published March 2 in Scientific Reports.
Scientists had known of an Adélie penguin colony (Pygoscelis adeliae) in these Danger Islands, but satellite images revealed more guano on the rocky islands than could be explained by the colony’s expected numbers.
Even though the tiny island chain is only about 10 kilometers across, researchers hadn’t realized the extent of the penguin population, says study coauthor Heather Lynch, an ecologist at Stony Brook University in New York. “In the Antarctic, distances are so vast, something major could be just around the corner and you wouldn’t know.”
The researchers did a preliminary head count, took drone images and collected mud cores during a 2015 expedition. The team then spent about a year using a computer algorithm to analyze the images to more fully count 751,527 penguin nests, Lynch says. For every nesting bird, the scientists assumed there was a partner penguin out at sea.
Next, the team hopes to analyze the guano content in the collected layers of mud to discover how long the penguins have been nesting in the Danger Islands.
The discovery is good news for fans of the flightless bird. Elsewhere in Antarctica where the climate is more volatile, penguin colonies are in decline. “I hope this provides impetus for a marine protected area in the Danger Islands with expanded borders from what has been proposed,” Lynch says.
STEM is an acronym. It was used originally by the US government to describe fields of study that helped immigrants get work visas: science, technology, engineering, and math.
Today, educators are linking these areas together in what is called STEM curriculum.
When we break down the acronym into its parts, we see that early childhood programs practice STEM activities every day.
Science activities include exploring water and sand, comparing and contrasting natural materials like rocks and soil, rolling balls across the room, and looking through a magnifying glass to count how many legs are on the bug that was caught during outdoor play.
Technology activities include computers, but also identifying simple machines like gears and wheels and pulleys.
Engineering in preschool happens in the block area. There children are planning and designing structures every day with little teacher direction.
Math activities include counting and matching shapes and making patterns. Measuring is easy too, especially with unit blocks where two of one size equal one of the next size up.
As a Little Professors teacher, you can expand kids’ science learning and lead them toward discovery by encouraging their natural curiosity; noticing what they are doing during play with water, shadow, or sand; and asking the right questions. You can get involved by asking children open ended questions: “Tell me what you are working on now.” “What do you notice about how it’s moving?” “What else have you seen other kids try?” Writing down their thoughts and ideas is a good way to document their growth in STEM curriculum to share with their parents.
Brain Building in STEM:
Science is a way of thinking. Science is observing and experimenting, making predictions, sharing discoveries, asking questions, and wondering how things work.
Technology is a way of doing. Technology is using tools, being inventive, identifying problems, and making things work.
Engineering is a way of doing. Engineering is solving problems, using a variety of materials, designing and creating, and building things that work.
Math is a way of measuring. Math is sequencing (1, 2, 3, 4…), patterning (1, 2, 1, 2, 1, 2…), and exploring shapes (triangle, square, circle), volume (holds more or less), and size (bigger, less than).
Asking the right questions:
You’ve probably noticed that preschoolers ask lots of questions when they’re exploring:
“Where do clouds come from?” “Why is the ice melting?” “Why is the ball rolling over there?” Sometimes it feels like no one educator could have all the answers to their questions. But we have good news for you—you don’t need to have the answers to create memorable STEM experiences. In fact, the key to effective STEM learning at the preschool level is asking great questions right along with the kids!
One strategy for asking great questions is focusing on “what” instead of “why.” When you ask “why” questions, it implies there is a correct answer and the child is being tested. For example, if you ask, “Why is the magnet sticking to that kind of metal?” you may be just as unable to answer that question as the child is. But when you ask “what” questions, you’re starting a conversation and exploring right along with your children. “What” questions focus on what is happening, what you are noticing, and what you are doing—and those answers are right in front of you and your kids. By focusing your questions on what kids have observed and noticed, not only are you helping them develop valuable communication and observation skills, but you are also building their confidence by giving them questions they can answer as experts.