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10 Rare Fossils of Species That Lived With Dinosaurs

Updated on September 22, 2017
Jana Louise Smit profile image

Jana is an amateur archaeologist who examined her first rock at the age of 2. She likes to group ancient discoveries together in fun lists.

Dinosaurs shared their forests with many other lifeforms.
Dinosaurs shared their forests with many other lifeforms. | Source

10. The Oldest Mushroom

A mushroom fossil may not sound like much but the oldest is considered a wonder of preservation. All previous prehistoric toadstools, a grand total of ten, were discovered in amber. Amber's quick ability to freeze anything in time is well-known but this fungus preserved in limestone. Given the fragile structure and quick decay rate of mushrooms, to have one fossilize in rock is extremely unlikely. Yet this 115 million-year-old specimen preserved so well that scientists could clearly see the modern-looking stem and frills.

It sprouted in the soil of Gondwanaland, Earth's super landmass before it broke up into continents. More exact, next to a river in present-day Brazil. At one point it ended up in the water, traveled into a lagoon and sank to the bottom where the high salinity and lack of oxygen halted decomposition. That it survived the journey intact is another miracle. The 1.97 inch (5cm) Gondwanagaricites magnificus was also an accidental find. A donation of fossilized insects were made to researchers who found the unique fungus between them. But when and how it was originally collected remains unknown.

Gondwanagaricites magnificus

The fossil mushroom and a sketch showing the gills, hood and stem.
The fossil mushroom and a sketch showing the gills, hood and stem. | Source

9. Undigested Skeleton

Around 220 million years ago, a dinosaur's stomach did not agree with a meal. In 1989, the fossilized puke was found in Northern Italy and the remarkable remains consisted of a curled up creature.

Back in the day, paleontologist believed the prey was a pterosaur, a non-dinosaur that cruised the skies. These winged reptiles came in sizes as big as fighter jets but the one in question was tiny. For decades, it was hailed as a rare case where a pterosaur got coughed up (if it went out the other end, the bones would have been mineralized).

During a more recent scan, the identity of the difficult lunch became more of a mystery. When compared to the bones of other pterosaurs, there was a mismatch. The remains more closely resembled a protorosaur, an aquatic reptile, but not a species similar to any found in the area. Nobody is really sure what refused to be digested but there is no other fossil like it.

8. Pig-Nosed Turtle

During a time when southern Utah was wet, humid and home to tyrannosaurs, an odd turtle paddled about in the water. Every other turtle known to man has a single nasal cavity inside the skull where the nostrils are divided by a fleshy barrier. But the 76-million-year-old Arvinachelys goldeni had two nasal canals made of bone, giving it a distinctive pig-like face.

The valuable fossil was found by scientists working in the 1.9 million acre Grand Staircase-Escalante National Monument. Usually, turtle fossils consist of just heads or shells. Such small parts can hardly, if ever, help solve how the reptiles evolved. The Cretaceous creature is not only the first to be found with the strange feature but possessed a skull, shell, partial legs and neck bones. The above-average amount of remains will undoubtedly aid studies aimed at understanding how fossil turtles related to each other and their places in the ecosystem.

7. Shark Nursery

In southwestern Kyrgyzstan an ancient nesting site for prehistoric sharks delivered countless still-sharp baby teeth and egg pouches. Aged around 230 million years, it is the first time both had been found at the same site. This made researchers speculate that the infant sharks stayed in the same area they hatched, perhaps even forming a school.

Back then, the sediment certainly had all the flora and fauna the babies needed to grow, since there were likely no parental care. Surprisingly, the nursery was shared by two different shark species and was located in fresh water. While the set-up resembles modern shark "nesting sites", no living female today will drop her eggs in fresh water. It is a riddle how the pouches survived. However, the switch from fresh to ocean water proves that sharks underwent major evolutionary shifts in some ways, contrary to the belief that they are living, unchanged fossils.

6. The Belone Bird

In 2014, a Chinese museum director acquired a piece of amber after hearing it contained some sort of lizard foot. An initial look quickly corrected that mistake - the claw belonged to a Cretaceous bird, not a reptile.

At first, researchers thought the 99-million-year-old cloudy amber contained only the feet of a hatchling enantiornithine. A CT scan revealed the true magnificence of the find. Almost half the baby bird was still inside, with feathers and skin, the head, both wings and a foot with nails.

Nicknamed "Belone", the bird's feathers might explain why only juvenile enantiornithes are found in large numbers from the Cretaceous and no other bird group. Something caused them to suffer a high mortality rate and early independence might be to blame. When it died, the amber specimen was only a few days or weeks old but already owned a full set of flight feathers. Being born with the ability to fly was a costly perk. This no doubt exposed the chicks to bad weather, hunger and other dangers normally negated by parental care. In the end, no bird species in the enantiornithes group survived. They all perished with the event that killed off the dinosaurs 65 million years ago.

5. Bird With Teeth

All enantiornithes had toothed beaks but a newly discovered species made this strange fact even more odd. The tiny bird had teeth with sharp, pointed crowns and enamel with serrated edges.

Unearthed in China, the 125 million-year-old fossil was in excellent condition and even came with food still in its stomach. When alive Sulcavis geeorum dodged pterodactyls and in turn, probably used its teeth to break the shells of snails, crabs and insects. The strange snappers explain more about the diet of the world's first birds but deepens a particularly sticky mystery.

Since birds began appearing in the fossil record, evolution removed their teeth four times. It is unclear why this happened or why birds had teeth in the first place when they don't need any today (though birds still carry genes for teeth). The main belief was that for flight to develop, birds shed any unnecessary weight and this included any dental features. However, Sulcavis geeorum was modern looking, almost like a songbird today and its flight was not affected by its small yet capable teeth.

4. The Transitional Phytosaur

Phytosaurs were Triassic reptiles and their fossils can easily be mistaken for early crocodiles. How they came to mimic crocodilians so closely is another difficult prehistoric question, mostly because their evolution story is missing. Phytosaurs are almost never found outside of Late Triassic layers and by then they already had their distinctive long noses and bodies.

In 2012, another Chinese find was published as a poposaur but an alert American scientist noticed it had phytosaur traits. Another examination confirmed that the new species, Diandongosuchus, was a still-evolving form of phythosaur. Ten million years older than the next known group, it showed that phythosaurs were already aquatic despite lacking several later features and was also much smaller. Unlike crocodiles, phythosaurs' nostrils sat near the eyes and not on the snout. Diandongosuchus' were somewhere in the middle of a shorter nose. The animal also did not have the special tissues that gave later cousins more powerful jaws.

The fossil, which is both the first transitional phytosaur and only one recovered from the Middle Triassic, added at least some understanding to the mysterious reptiles. It would appear that they followed the crocodilians' change away from their own smaller version to become large apex predators comfortable on land and in water.

Diandongosuchus fuyuanensis

An artist's impression of the new phythosaur.
An artist's impression of the new phythosaur. | Source

3. Madagascar's Super Mammal

In 2010, researchers found the skull of a groundhog-resembling mammal that roamed Madagascar 72-66 million years ago. Vintana sertichi was so unusual that not even the experts saw it coming. Showing both reptilian and mammalian traits, the creature busts the myth that dinosaur-era mammals were small and underdeveloped. At 20 pounds (9 kg), it was unusually big and the skull's features revealed super sensory skills. A massive 14 percent of its brain was dedicated to smell (as opposed to a dog's 0.31 percent). The design of the eye sockets and inner ear suggested that Vintana had excellent night vision, high-frequency hearing and agility. The brain case itself was oddly sloped, thick boned and porous.

The value of this fossil is immense. The animal belonged to a mysterious group of mammals called Gondwanatherians, known only from a few bone fragments first found 30 years ago. Any information capable of identifying their branch on the animal family tree was nonexistent until Vintana showed up. The peculiar skull helped to place Gondwanatherians in an existing collection known as Allotheria. While it managed to place entire species, little is known about Vintana itself other than it was a herbivore with an odd head and super senses.

Vintana sertichi

Here Vintana's size is measured against a human. During the dinosaur era, this was a surprisingly big size for mammals to reach.
Here Vintana's size is measured against a human. During the dinosaur era, this was a surprisingly big size for mammals to reach. | Source

2. Plesiosaur Attack Survivor

What is being called the best evidence for direct plesiosaur predation is basically a bitten bone. The 80 million-year-old leg belonged to a Hesperornis, a large sea bird. The fossil languished in storage for decades before scientists recognized a bony bump near the ankle as a healed injury.

After matching the jaws of several fossil predators against dents found near the wound, an almost perfect fit came from a juvenile plesiosaur's teeth. These man-sized carnivores had long necks, small heads and flippers. The bite represents one of only two confirmed plesiosaur attacks in the fossil record but is the first to add ocean birds to the reptile's diet, something not widely accepted before.

What made it even rarer is that paleontologists cannot usually tell from fossil bites if the prey was dead or alive when tooth met bone. In this case the bird was definitely alive. The angle of the chomp showed that the marine reptile chose to attack from the side and managed to grab the entire leg of the Hesperornis. The lump that first attracted the researchers' attention was caused by an infection, likely brought on by the event. The fact that it healed suggests the bird survived both the bite and the infection that followed.

Sanajeh and the Sauropod

A museum display captures the prehistoric drama.
A museum display captures the prehistoric drama. | Source

1. A Dinosaur-Hunting Snake

The last thing a mother dinosaur wants to see in her nest with eggs is a large snake. Minus the mom, this scenario was preserved almost 67 million years ago in India. Curled up between a pair of eggs, the 11.5-foot (3.5 m) serpent died while staring at a newborn sauropod, the massive long-necked herbivores most people are familiar with.

The baby perished with it, probably from a sudden mud slide that buried the entire nest. The frozen drama is the first evidence that snakes preyed on dinosaurs. Some feel the snake, Sanejeh indicus, could have slithered in to the nest for reasons other than stalking a hatching dinosaur. However, the reptile was more than capable of gorging on the sauropod, despite that the infant was already 1.6 foot (0.5m) long. The snake was both big and had jaws that moved independently of each other. That way the mouth could wriggle until it enveloped the prey. If this was indeed an interrupted hunt, it makes for a change from the usual dinosaur-eat-dinosaur fossils and show the rarely-seen dangers that lurked around nestling dinosaurs.

References

Link 1: https://www.theguardian.com/science/2017/jun/07/fossil-mushroom-discovered-from-the-era-of-the-dinosaurs

Link 2: https://www.seeker.com/dinosaur-puke-fossil-mystery-deepens-1770468641.html

Link 3: https://www.britannica.com/animal/protorosaur

Link 4: https://www.seeker.com/weird-pig-nosed-turtle-from-dinosaur-era-found-in-utah-1770368795.html

Link 5: https://www.blm.gov/programs/national-conservation-lands/utah/grand-staircase-escalante-national-monument

Link 6: http://www.nbcnews.com/id/44444099

Link 7: http://news.nationalgeographic.com/2017/06/baby-bird-dinosaur-burmese-amber-fossil/

Link 8: https://www.livescience.com/25998-ancient-bird-strange-teeth.html

Link 9: https://m.phys.org/news/2017-06-diandongosuchusthe-strange-faced-transitional-phytosaur.html

Link 10: http://news.nationalgeographic.com/news/2014/11/141105-mammal-evolution-vintana-fossil-science/

Link 11: http://www.bbc.com/earth/story/20160311-how-a-bird-managed-to-escape-a-predatory-sea-monster

Link 12: http://news.nationalgeographic.com/news/2010/03/100301-snake-eats-dinosaurs-fossils-sanejeh-indicus-scitech/


© 2017 Jana Louise Smit

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