Animals

Ancient Sea Monsters Were Black

Some of the largest beasts in the ancient seas had black skin or scales, new research finds.

Some of the largest beasts in the ancient seas had black skin or scales, new research finds.

Ancient leatherback turtles, toothy predators called mosasaurs and dolphinlike reptiles called ichthyosaurs all had black pigmentation, researchers report today (Jan. 8) in the journal Nature. The findings come from an analysis of preserved skin from each of these creatures.

The animals' blackness likely helped them in a variety of ways, said study researcher Johan Lindgren, a mosasaur expert at Lund University in Sweden. "We suggest ... that they used it not only as camouflage and UV protection, but also to be able to regulate their body temperature," Lindgren told LiveScience. (Sea Monster Album: See Images of Extinct Mosasaurs)

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Ancient colors The study isn't the first to delve into the color of ancient creatures. Paleontologists have found that Microraptor, a small winged dinosaur from 130 million years ago, had black, crowlike feathers. The "dino-bird" Archaeopteryx had wing feathers with a black-and-white pattern, too, according to a 2012 study detailed in the journal Nature Communications. The color of ancient feathers is somewhat controversial, however, with some scientists suggesting the fossilization process might distort the pigment-containing organelles in the feathers.

But marine animal color was uncharted territory. Some fossils of extinct sea monsters have been found with black "halos" around the bones, suggesting remnants of skin. Anatomical analysis suggested these remnants were, in fact, melanosomes, the tiny packets of pigments that give skin, feathers and hair their color. Melanosomes contain melanin, a dark brown or black pigment. In fact, the black pigment eumelanin is extremely persistent in the environment, Lindgren said, so the presence of melanosomes may be the reason these skin halos survived.

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Lindgren and his colleagues conducted a microscopic analysis of the fossilized skin of a 55-million-year-old leatherback turtle, an 86-million-year-old mosasaur and a 190-million year-old ichthyosaur. Mosasaurs were reptilian, fishlike apex predators in the Cretaceous seas. Ichthyosaurs were also marine reptiles, but with their long snouts, they resembled modern dolphins.

Dark and dangerous A microscopic look at the fossils showed oval bodies consistent with the look of melanosomes. To confirm that the oval bodies were melanosomes, the researchers used a technique called energy-dispersive X-ray microanalysis, which focuses X-rays on the sample. The reaction of the sample depends on its chemical makeup. This analysis showed that the tiny ovals were associated with the preserved skin film, but not with the sediment around it, suggesting they are really melanosomes and not microbial contamination.

To understand how ancient sea creatures benefited from black skin and scales, Lindgren and his colleagues turned to the only sea turtle that stays black into adulthood: the modern leatherback turtle (Dermochelys coriacea). These turtles have a broad range, all the way into the Arctic circle, and the color seems to help them trap heat from sunlight in the same way that black asphalt gets hot on a bright day, Lindgren said. Black pigments also protect the skin from damage from UV rays (also known as sunburn). Mosasaurs, ichthyosaurs and ancient may have gotten a similar advantage from their coloration.

Black skin and scales may also have helped these creatures stay stealthy in the dark seas. Living leatherback turtles are dark on top with light underbellies, so they blend in with the depths from above and with the sunlight at the surface from below. Many ocean-dwelling creatures show this coloration pattern, Lindgren said, but the fossil skin samples from the ancient turtle and mosasaur are too small to say for sure whether they shared countershading camouflage.

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Ichthyosaurs are a different story. Some ichthyosaur fossils consist of skeletons surrounded completely by an "envelope" of dark material. If these envelopes prove to be entirely skin remains, Lindgren said, they would suggest that ichthyosaurs were completely black. That coloration would make them like modern sperm whales, which dive deep into murky waters - as ancient ichthyosaurs also may have done.

"Of course, that may be a coincidence, but it's an interesting similarity that they share," Lindgren said.

The techniques used in the study may also be able to resolve debate over the coloration of land animals, he said, differentiating whether suspected melanosomes come from the fossil or from microbes.

Original article on LiveScience.

Image Gallery: Ancient Monsters of the Sea Dangers in the Deep: 10 Scariest Sea Creatures Image Gallery: 25 Amazing Ancient Beasts Copyright 2014 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Fossil pigments reveal dark coloration of extinct marine reptiles. The mosasaur (bottom) have a dark back and light belly, a camouflage pattern, and the ichthyosaur (center) is uniformly dark.

Monsters Ho!

We all enjoy a tall tale. Cultures with seafaring traditions are especially ripe in what seem like the tallest sea monster tales of all: hydra, kraken, sirens, scylla, leviathans, assorted serpents and mermaids. Usually the stories are never confirmed and usually baseless.

Then again, some of the tales are based on something, or so we are learning as marine scientists plumb the depths and discover some pretty weird creatures. The bottom line: There really are bizarre, unexpected, totally startling monsters found in the seas. And the very worst of these is the most unexpected.

Japanese Serpents

Sea monsters are truly global. This one from Japan serves as the villain for the classic maiden in distress, who awaits rescue by her hero. The poor monsters are almost always cast as the bad guys. And so they usually end hacked to pieces; fish food.

But is there any truth behind these sea serpent tales?

Improbable, But True

Maybe it's the oarfish. It looks too monstrous to be true. It can grow many meters long, has strikingly bright silver scales, scarlet fins and some ornate headgear that more than explains why some call it a roosterfish. If only it were a reptile, it'd be a true sea serpent.

Alas. It is a fish. A very weird and beautiful fish, but still a fish.

Largest Serpent of All

There are also other, newfound "sea serpents" our sea-going ancestors never imagined. This one was spotted by a satellite coiling off the south coast of Japan's Hokkaido island.

What do we know about it? 1) It's arguably one of the largest organisms on Earth, 2) It swallows ships, engulfs islands and generally does what it wants, and 3) We're darned lucky it's made of plankton.

Research into such massive blooms and the individual plankton cells that comprise them has revealed surprising cooperation among the microorganisms. They appear to operate like more than just floating individual cells. They live and die for the greater good, it seems. So they may be, in fact, a gigantic watery superorganism.

Now that's a cool monster for you: You can swim in it and never know you've been in the belly of a beast.

The Hokey Hybrids

Mermaids and mermen have always been the stuff of fantasy. Where did the fantasies come from? There are some standard answers to this question, which have always seemed rather inadequate. For instance ... (next slide, if you please) ...

Mer-Manatee?

The manatee has often been called the source of mermaid myths. It's a mammal, so it breathes air. But who would ever mistake a manatee for a sleek and beautiful mermaid?

Could it be love-starved sailors with poor eyesight? There was no shortage of these fellows in the days before optometrists.

Grandpa Fish

Another possibility is that merfolk were inspired by fish with roughly human-looking faces, like this fellow. Some fish can look humanoid. That would be enough to get superstitious sailors started.

The Kraken Strikes

How about giant, ship-destroying squid and octopi? These monsters were old hat even to the easily freaked-out. Most folks figured they were historical exaggerations.

That's until some very large and unusual squids started washing up or being hauled in by marine biologists in recent years. Colossal squid are meters long, pretty amazing beasts. Still, they have never been known to lift ships out of the water.

And since were on the topic of squids ...

Spider + Bat + Squid = Sea Monster

Do you remember when this one hit the headlines? It's not so gigantic, at four meters long, but it was observed 3,380 meters down in the Pacific Ocean near Oahu. It's pretty big to have gone unseen before its May 2001 discovery.

So what else is out there? It's pretty clear marine biologists have only just begun discovering what lives in the deep sea. The more time they spend searching, the more they will find. But none would dispute that the nastiest sea monster to ever rise out of the sea is ... (drum roll please) ...

Deadliest Sea Monster Ever

You might have guessed it: Human garbage. Yep. It's the ugliest, most alien-looking, fatal and pervasive monster in the seas. Garbage patches have been getting a lot of attention lately. These are areas on the seas where currents and winds tend to concentrate floating garbage.