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10 Fascinating Fossils With Mysteries or Rare Features

Jana loves researching and sharing facts about the natural world, science, and history.

Fossils help piece together history before humans.

Fossils help piece together history before humans.

10. A Pregnant Reptile

Ichthyosaurs were marine reptiles that lived alongside the dinosaurs. They came in several species and were good enough to leave their bones all over the place. Not only are they common in the fossil record but they also appeared to have been prolific breeders. The very first ichthyosaur, found in 1846, carried an embryo. Ever since then, eight species of ichthyosaur have produced fossilized pregnancies.

In 2010, a man from Yorkshire added an ichthyosaur to his rock collection. He suspected that some of the bones were embryos. After he contacted paleontologists, they confirmed that it was a female with around eight babies. Additionally, the remains could be as old as 200 million years—making them the oldest ichthyosaur embryos in the United Kingdom. The fossilized family was donated to the Yorkshire Museum for further study and preservation.

An Ichthyosaur skeleton at London's Natural History Museum.

An Ichthyosaur skeleton at London's Natural History Museum.

9. The Biggest Parrot

The world's biggest parrot, Heracles inexpectatus, measured 1 meter (3 feet) high and weighed as much as 7 kilograms (15 pounds). Unfortunately, it went extinct millions of years ago. The species came to light when two leg bones were found in 2008, in New Zealand. Scientists only realized what a lucky find it was after they searched for ten years and found no additional fossils of the bird.

The pair of bones were thick-walled and robust. This was a good indication that Heracles was flightless, climbed trees and glided back to the ground when necessary. Coincidently, this is a perfect description for the biggest living parrot—the Kakapo. Heracles most likely feasted on the fruit from the subtropical rainforest that existed at the time. Around 13 million years ago, however, temperatures dropped all over the world and the island's fruit trees became fewer. This probably killed off the magnificent parrot.

8. An Even Bigger Penguin

In 2019, another giant bird was rediscovered in New Zealand. An amateur paleontologist working in Canterbury found the fossilized leg bones of a penguin. The biggest penguin today is the emperor, a bird that can grow 1.2 meters (3.9 feet) tall. The new species, Crossvalia waiparensis, would have dwarfed the emperor as it stood 1.6 meters (5.3 feet) high. However, the New Zealand whopper was not the biggest penguin that ever lived. That honor went to Palaeeudyptes klekowskii, which measured 2 meters (6.5 feet) tall and lived 37 million years ago.

The new penguin thrived shortly after the dinosaurs died out 66 million years ago and had unusual legs. The bone structure showed the birds either swam more than penguins today or never adapted to standing upright. While that was unusual in itself, giant penguin species represent another mystery. Due to their size, they had more body heat, fewer predators and could dive deeper for prey. It remains unknown why penguins shed the pounds and benefits when they shrunk down to their modern sizes.

7. The Discovery of Ngwevu Intloko

Most new dinosaur species are discovered during excavations. Rarer, however, is for a new dinosaur to masquerade for decades as a common species. That was the case of Ngwevu intloko. When it was found 40 years ago, the animal was identified as Massospondylus carinatus. The latter was the most abundant dinosaur species in South Africa and as a result, well studied and easily recognized.

The new fossil was slightly different but researchers decided that it was just an odd M. carinatus, perhaps one with a deformed skull. In 2019, high-tech scans found the animal was an adult but that its “deformity” was nothing of the sort. This was a new species that resembled M. carinatus, lived during the same time but it was smaller and walked on two legs. The discovery could prompt a new look at all M. carinutus fossils (and there are plenty) to oust any N. intloko hiding among them.

The scans that revealed a new species.

The scans that revealed a new species.

Recently, scientists went wild. They found a dinosaur species that crawled as a baby before it walked on its hind legs as an adult. This made it the only other species besides humans that made the transition from crawling to walking upright as they aged. In 2019, somebody popped that happy balloon with a needle. The dinosaur in question was Mussaurus patagonicus, an Argentina native that lived 200 million years ago. Their fossils include specimens that died at different ages and it was the discovery of a small baby that led some to believe their newborns crawled.

However, a new study used the various age groups to determine the animal's center of gravity for each life phase. They confirmed that the herbivore did not walk upright after birth. In fact, it was incapable of doing so. During the first year of life, M. patagonicus had a “forward” center of gravity. Had they attempted to walk like an adult, the youngsters would have pitched face-first into the dirt. However, there was no crawling involved. They walked normally on four legs for about 12 months until their center shifted backward and they rose on their hind legs.

5. The Dead Shoal

When Arizona scientists paid a visit to colleagues in Japan, they were shown a unique fossil. The rock showed 259 fish of the same species, the extinct Erismatopterus levatus. It was some kind of nursery shoal since they were all babies. The slab was held at a Japanese museum, but a new study in 2019 proved that it originally came from a vein of the earth that ran through Utah, Wyoming, and Colorado.

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Apparently, around 50 million years ago, the school was instantly trapped when they encountered a landslide. They became pressed like flowers, in position, and this made the fossil very valuable. The distance between each fish, their direction and postures proved the shoal followed the same movement rules as modern schools and indeed, was the oldest evidence that prehistoric fish even had shoals.

4. A Shark Attack

In 2011, North Carolina miners found a large bone. Strangely, it had three dents spaced 15.2 centimeters (6 inches) apart. Paleontologists identified the bone as a rib of a whale that lived 3 to 4 million years ago. The piercings came from a bite. The only teeth that fit belonged to the extinct Carcharocles megalodon, a shark of nightmarish proportions. The whale's species was unclear but it could have been a forerunner of the humpback or blue whale. It survived the attack, which was a surprise considering how formidable megalodon was.

For a while, tissue regenerated around the tooth marks and the entire rib became covered in woven bone. This material is the body's first line of defense against a broken bone or a serious infection. It forms quickly after the initial injury to help with healing. However, the amount of woven bone on the specimen and the incomplete recovery of the piercings showed that the whale eventually succumbed two to eight weeks later, probably from a massive infection. Despite the whale's death, the rib remains a rare example of prehistoric prey surviving the attack meant to kill it.

3. Mystery of the Missing Legs

Arthropods include butterflies, centipedes, spiders, and crabs. For a long time, it remained unclear where they got their legs from. Researchers had a notion that arthropod limbs started with a common ancestor, the anomalocaridid. However, none of their fossils showed any appendages that qualified as something that might sprout into legs. Anomalocaridids lived 480 million years ago and at 2.1 meters (7 feet) long was one of the largest animals of its time. Resembling a lobster-squid hybrid, they zipped around the ocean and filtered plankton as food much like whales today.

In 2015, a remarkable specimen was found in the Sahara Desert. Other anomalocaridid fossils were squashed flat but this one's 3D anatomy provided a startling insight into arthropod evolution. Scientists have always known the animals had side flaps for swimming. However, the Sahara fossil clearly showed a second set that appeared to be modified legs. The discovery closed a huge evolutionary gap for arthropods. The new flaps became legs in modern arthropods while the higher flaps became gills.

An artist's impression of the peculiar anomalocaridid.

An artist's impression of the peculiar anomalocaridid.

2. Glass Pearls

More than a decade ago, a researcher dug for ancient clams. He pried them open to find a particular single-celled organism he was after. Instead, the clams contained tiny spheres. These “pearls” were put aside and forgotten. In 2019, the same scientist decided to study the unexpected artifacts. They turned out to be silica-rich glass and normally, such globes are formed during volcanic processes. However, they were found in a part of Florida that never saw any volcanic activity. Something else created them. Something hot.

The likeliest culprit was a prehistoric meteorite that punched the Earth and shot scorching debris into the air. The melted bits in the atmosphere cooled into glass spheres and fell back where they eventually ended up inside the clams. Mysteriously, the clams date from four different eras and altogether span from 5 million to 12,000 years ago. This suggested that there were multiple impacts in Florida. Alternatively, one meteorite's fallout could have endured in the environment for an exceptionally long time.

1. The World's Strangest Toe

In 2019, scientists found something that matched nothing in the natural world, both living and extinct. What was this oddity? A really long toe. It belonged to a new bird (Elektorornis chenguangi). Unfortunately, only the foot was preserved inside a 99-million-year-old piece of amber. Scientists may never know what the bird looked like except that it was smaller than a sparrow.

Once the team realized that the toe was unique, they tried to establish its purpose. The 9.8 millimetres (0.38 inch) long middle toe suggested that the bird probably lived in trees. It was perfect for gripping a branch or scooping prey from crevices in the bark. The toe could also have played a role in an unknown ecological niche that no longer exists, one that had nothing to do with sitting in a tree or digging for dinner. There is no real answer for the world's weirdest toe.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2019 Jana Louise Smit


Jana Louise Smit (author) from South Africa on October 08, 2019:

Thank you, Lorna. It would've been amazing the see the actual bird too. Who knows? Maybe one day we will. :)

Lorna Lamon on October 08, 2019:

I was fascinated by this article Jana which is not only interesting by educational. I enjoyed reading about 'The world's strangest toe' belonging to a new species of bird. Great article.

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