Enlarge / Diplodocus dinosaur scene from the Jurassic era 3D illustration (credit: Warpaintcobra )

Finding any fossil skin is extraordinary; finding dinosaur skin is that much more rare. So when Tess Gallagher and her mom excavated patches of skin from one of the largest dinosaurs to exist, there was reason for jubilation.

More than a year later, that glee disintegrated—right along with the skin they excavated. But what could have been the end of a sad story was merely the beginning of another exciting chapter, one that could potentially broaden our understanding of how these enormous creatures cooled themselves.

Found and lost

Gallagher, now a paleontologist and paleobiology graduate student at the University of Bristol, and her mother, Lisa Marshall, were part of a team excavating a site called the Mother’s Day Quarry in Montana. The site has produced, among other things, 15 individual Diplodocus juveniles from about 145 million years ago.

Enlarge / A great white shark. (credit: wildestanimal / Getty Images)

Gigantic extinct sharks have something to tell us from millions of years ago, and paleontologists are only just beginning to unravel that message. In a series of firsts, paleontologists have identified a growing number of paleo-nurseries, ancient sanctuaries where young sharks may have been born and where they grew until they were big enough to survive on their own in the larger sea. It’s a strategy some sharks continue to employ today, meaning it has been a successful evolutionary tactic for at least 23 million years.

The most abundant remnants we have of these apex predators are the teeth they shed over their lifetime. Cartilage, the major component of internal shark structure, doesn’t tend to survive fossilization. Given the considerable dearth of fossils, how can paleontologists ascertain the types and ages of extinct sharks? And how are paleontologists able to determine the site of a paleo-nursery from tens of millions of years ago in areas that are no longer underwater?

Answers with teeth

The answers lie with fossil teeth, from which paleontologists can determine species and estimate sizes—and, remarkably, the temperature and salinity of the water where the sharks lived. Although scientists aren’t yet able to establish the precise age of a shark from a fossil tooth, they can narrow it down to whether the shark was a neonate, juvenile, or adult, according to Matthew Gibson, the natural history curator at The Charleston Museum.

A team of Australian scientists has discovered the world's oldest heart , part of the fossilized remains of an armored fish that died some 380 million years ago. The fish also had a fossilized stomach, liver, and intestine. All the organs were arranged much like similar organs in modern shark anatomy, according to a recent paper published in the journal Science.

As we've reported previously , most fossils are bone, shells, teeth, and other forms of "hard" tissue, but occasionally fossils are discovered that preserve soft tissues like skin, muscles, organs—or even the occasional eyeball. This can tell scientists much about aspects of the biology, ecology, and evolution of such ancient organisms that skeletons alone can't convey.

For instance, earlier this year, researchers created a highly detailed 3D model of a 365 million-year-old ammonite fossil from the Jurassic period by combining advanced imaging techniques, revealing internal muscles that had never been previously observed. Among other findings, the researchers observed paired muscles extending from the ammonite's body, which they surmise the animal used to retract itself further into its shell to avoid predators.

Enlarge (credit: Aurich Lawson/T. Clements et al.)

Sometimes science can be a messy endeavor—not to mention "disgusting and smelly." That's how British researchers described their experiments monitoring dead sea bass carcasses as they rotted over the course of 70 days. In the process, they gained some fascinating insights into how (and why) the soft tissues of internal organs can be selectively preserved in the fossil record, according to a new paper published in the journal Palaeontology.

Most fossils are bone, shells, teeth, and other forms of "hard" tissue, but occasionally rare fossils are discovered that preserve soft tissues like skin, muscles, organs, or even the occasional eyeball. This can tell scientists much about aspects of the biology, ecology, and evolution of such ancient organisms that skeletons alone can't convey. For instance, earlier this year, researchers created a highly detailed 3D model of a 365-million-year-old ammonite fossil from the Jurassic period by combining advanced imaging techniques, revealing internal muscles that had never been previously observed.

"One of the best ways that soft tissue can turn into rock is when they are replaced by a mineral called calcium phosphate (sometimes called apatite)," said co-author Thomas Clements of the University of Birmingham. "Scientists have been studying calcium phosphate for decades trying to understand how this process happens—but one question we just don’t understand is why some internal organs seem more likely to be preserved than others."

Enlarge (credit: Julius Csotonyi)

A group of researchers has recently made an astounding discovery.

Using an innovative imaging technique, an international team of scientists has uncovered remarkable details of a pterosaur's soft tissue. Despite an age of approximately 145–163 million years, the wing membrane and the webbing between both feet managed to survive fossilization.

Armed with new data, the team used modeling to determine that this little pterosaur had the capacity to launch itself from the water. Their findings are published in Scientific Reports.

Enlarge (credit: IVPP )

An extraordinarily well-preserved fossil owl was described in PNAS this past March. Owls are not new to the fossil record; evidence of their existence has been found in scattered limbs and fragments from the Pleistocene to the Paleocene (approximately 11,700 years to 65 million years ago). What makes this fossil unique is not only the rare preservation of its near-complete articulated skeleton but that it provides the first evidence of diurnal behavior millions of years earlier than previously thought.

In other words, this ancient owl didn’t stalk its prey under the cloak of darkness. Instead, the bird was active under the rays of the Miocene sun.

Seeing the light

Its eye socket was key to making this determination. Dr. Zhiheng Li is the lead author on the paper and a vertebrate paleontologist who focuses on fossil birds at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in China. He explained in an email that the large bones around the eyes of birds (but not mammals) known as the scleral ossicles offer information about the size of the pupil they surround. In this case, the pupils of this fossil owl were small. And if the pupil is small, he wrote, it “means they can obtain good vision with a smaller eye opening.”