- Education and Science»
- Life Sciences
The Strangest Cambrian Creatures Ever Discovered
It All Begins...
The Cambrian Period (542-488 million years ago) is known as being the first burst in the diversity of animal life. It wasn't that animals didn't exist before this time, as they did, that made this period special. In fact the oldest worm known has been dated to be a billion years old which vastly outdates the Cambrian period, but this is a time when life was suddenly seen in great abundance and the immense variety that starts to approach the current population of earth. This was a time of strange creatures when mother nature was just starting out. If you know nothing of Cambrian life forms you might think some of them are someone's depiction of what aliens on another planet must look like. They range from familiar to utterly bizarre. So I'm inviting my readers to come with me on a written safari to gawk and awe at some of these odd little critters.
Trilobites are probably one of the best known Cambrian creatures. They came in hundreds, if not thousands of species, and most had an uncanny resemblance to pill bugs or certain types of cockroaches. Most of them looked rather benign and didn't grow very big but several of these little critters evolved some very strange attributes. Today I'll run through three of these species.
· Ceratarges: Ceratarges are a rare and fantastic find. They are generally unearthed near Morocco and can sell for a few hundred to a few thousand dollars. Unfortunately there's scant little information besides their marketability out there... Still one must speculate what those extra spines were for. Perhaps this made them less likely to eaten by the predators of the day. Were these spines solid enough to withstand an attack or did they detach like porcupine quills? Were they filled with venom like a scorpion? These are some of the questions that many paleontologists would love the answer to, unfortunately without the aid of a time machine we're not likely to figure it out.
· Walliserops: Walliserop is another oddity we're not too sure about. This little guy seems to be a cross between a hissing cockroach and a table fork. What did he use his fork for? Since no animals exist that are remotely like this we are left to speculate. Perhaps he used it to search for and eat food. Perhaps it was part of a mating display. Perhaps only males had these (or only females!) Perhaps it was some sort of defense mechanism or perhaps he used it to burrow in the sand. One of the strangest aspects of this one, besides his fork, is his species tendency to favor asymmetry. Most other trilobites are perfectly symmetrical but not little walliserops! They have been known to curve to one side or the other and their wee trident as well isn't exactly a study in perfect symmetry.
· Dicranurus monstrosus: This aptly named trilobite has so many spines you almost can't tell what's what. Two amazing spines curl over it's back in a fantastic antennae-like way. Other spines jut out in every direction. like the other two trilobites mentioned he also lived in the area we now know as Morocco.
The oldest jelly fish actually predates the Cambrian explosion (with the oldest dating back to 500 million years) but they were around during the Cambrian as well. Being soft creatures without any bones or hard shells they are a hard find as far as fossils go but they are discovered every now and again. They still exist in our oceans today much as they did in the Cambrian oceans and still are some of the strangest creatures around. Most have heard that jellyfish don't have a brain and have tossed this aside as urban legend but it is true, jellyfish do not have a brain, or a nervous system for that matter. This is because jellyfish aren't actually one creature, rather they are a number of small organisms that are working together in a colony to make up what appears to be one creature. They are made up of 95% water and are anatomically strange. Their "mouth" is used to eat fish, get rid of wastes, and throw up sperm/eggs. At different points in their life they can reproduce both sexually and asexually. They're quite a conundrum...
Myllokunmingia - Fish Ancestor
Vertebrates, animals with internal bones, have remained elusive in the early fossil records. For many years paleontologists thought that animals like fish didn't show up until after this initial explosion of life but a new discovery in China is calling that all into question. The creature in question, Myllokunmingia, is 530 million years old and although it doesn't have hard bones its head and several other features seem to have been made of cartilage. This probably made the animal flexible and swift. It may have been the granddaddy of all sharks and fish.
Ammonites are one of the most abundant forms of life found in the Cambrian fossil record. They were early mollusks that evolved from animals with straight long shells. They predated the mollusks of today that include squid, octopi, and the nautilus which is their closest living relative (but probably not a direct descendant.) The various species of ammonites evolved and went extinct so fast that paleontologists often use them to date other fossils found with them. Eventually they would grow to enormous size, the largest specimens reaching ten meters in length, or three meters in shell diameter, but in the beginning they weren't of any substantial size. These creatures survived several mass extinctions before most went the way the dinosaurs at the same time. Today nautiluses and other mollusks are our only living reminder they existed but that's not to say they didn't have fantastically long run in our planet's evolutionary history!
Fuxianhuia - Insect Mother?
Fuxianhuia was an early arthropod which means she was a likely candidate to be the mother of both crustaceans and insects. Recent discoveries have found that she had eight limbs under her head that would help her shovel food in her mouth. Perhaps more importantly she shows a key adaption - a nervous system that extended past her head. She is the oldest creature known to have this.
As you can tell from the name Hallucigenia is a strange "dream-like" creature. It doesn't seem to have terribly much anatomy that we can point to and be familiar with. In fact the soft blob-like "head" might not actually be its head. It has both stiff tentacles with pincer tips and jointed spines. Figuring out how this thing moved has been practically a paleontologist's version of a party game. There has been speculation that this animal might actually be just piece of a bigger animal we've yet to find. If not it sired no known living-day descendants so we might be pondering this one for awhile.
Odontogriphus was an odd slug-like creature that was less than 5 inches in length. It lived on the sea floor likely scraping up algae with its odd toothy-tongue. Biologist believe it may have been the predecessor of mollusks like clams, sea slugs, and squid.
Horseshoe crabs are fascinating little creatures. I know, you probably only know them as odd living room ornamentation but really there's more to them then that! Did you know for instance that horseshoe crabs have anti-freeze colored blue blood? Its copper based and used in the medical profession to test the purity of pharmaceuticals. For all you horseshoe crab lovers out there, don't fear, though a third of their blood is harvested for this use when they crawl ashore they are returned alive and are capable of replacing their lost blood (which is usually more than a human can loose and live from!) Horseshoe crabs are anatomically a bit strange as well. They eat worms and other small things in the sand and use their spine like tail to change direction and guide them, not to stab anything. They have 300 flat gills and some of the oldest compound eyes on record. It takes up to twelve years for them to grow to full size and usually live around twenty years although some forty year old captives have been recorded. They’re also related to spiders, oddly enough.
Opabinia is a fun one. Eyes actually first appeared in the Cambrian period, and they were all compound eyes (like you'd see on a fly.) Opabinia however has the current world record for the most eyes normally seen on one animal. They had five each. Why five? We have no idea. This asymmetrical number is a bit odd! It wasn’t a big creature, only three inches in length, but it was an interesting creature. It may have used it's trunk and pinchers to catch even smaller critters for dinner. Or perhaps it dug dinner up with it's strange appendage. It was first discovered in the 1970s and to date only about twenty specimens have been found. It's been an interesting animal to speculate upon.
The Anomalocaris is the rock star of the Cambrian fossil record. It was earth's first "super predator" growing up to six feet long, an astonishing size considering most of the other living animals around were maybe the size of cockroaches. It was indeed the largest animal known to life on earth in the Cambrian period. It had a bizarre circular mouth with grinding teeth and two strange arm-like appendages it probably used to sweep unsuspecting trilobites into its mouth with. Originally it was thought to have been three separate animals as paleontologist first found its mouth, it's arms, and it's body all separate. It moved by undulating the segments on its sides and ironically enough may be an ancestor of today's shrimp.
Anomalocaris in action
Hurdia was another enigma to science. Like its relative the anomalocaris it was thought to be a bunch of different animals when it was found in parts. Only when a full specimen was found did the big picture come to light. Even so it remains a mystery. It grew a foot and a half long and had a weird completely hollow head shield. We have no idea what this was used for. Some speculate it may have been used to help the animal go up and down in the water like a little submarine but this is just a guess. We don't even know for certain if this animal was a predator, which is likely considering its size, or a herbivore.
Banffia look like weird bloated tadpoles and are so strange they are currently not known to have any living relatives. They appeared in the fossil shale of Scotland in 1911 and have been baffling paleontologist ever since. It is guessed that these animals probably lived on the sea bottom and sifted food out of the sand it had swallowed, much like a sea cucumber today, but we can't even be certain of that much. They were small animals growing only to about four inches long and may have congregated in large numbers.
Sea Urchins (?)
I am not totally sure sea urchins are from the Cambrian period, so if you know they are not please tell me! [*Someone was kind enough to comment and tell me that Sea Urchins are actually somewhat younger, having evolved 450 million years ago in the late Ordovician period. Thank you Jon!]
Well, despite the confusion I did still write about sea urchins so I think I'll leave this bit in for now even though they're not technically Cambrian.
Sea Urchins are almost their own class, but not quite. They come in all sorts of colors (black, green, red, and purple among them) and biologists think they may be able to live for more than two hundred years. In fact even geriatric sea urchins seem to be able to spawn more sea urchins. They don't have too many predators but are enjoyed by sea otters and some types of eels. They themselves tend to feast on algae. They are currently being used to study the evolution of the immune system.
If you enjoyed this article you might like these other articles by Theophanes: