Kathi writes about fossils and other earthly subjects, plus the natural fauna of Michigan, features in her community, poetry, and more.
Much has been written and portrayed about dinosaurs and the fury of T-Rex in popular culture, but are you aware there were giant creatures dominating Earth's oceans long before the dino-era that ended 65 million years ago? Enjoy the following journey of giants and strange creatures through the timetables beginning with the Cambrian Period from 542 million years ago and ending 488 mya. Incidentally, according to scientists, the Cambrian is the first period in earth's history representing the arrival of complex organisms.
Anomalocaris dominated the Cambrian seas for tens of millions of years. It grew to only two feet (60 cm) long, which doesn’t seem very big by today’s standards, but in relation to every other organism during the Cambrian, it was a giant.
Interesting history of its stalled scientific discovery: A segment fossil of Anomalocaris canadensis was first discovered in the Canadian Rockies in 1892, but it wasn't until 1981 that a major breakthrough about its identity occurred; and that was further refined in 1996. This one hundred year history of inaccurate theories is but one example of the difficulty identifying fossil remains of Cambrian organisms having no apparent living descendants. Anomalocaris and other genera have since been discovered at various Cambrian fossil locations around the world, including the famous Burgess Shale site in the Canadian Rocky Mountains, the USA, China, and Australia.
Anomalocaris with its large eyes, impaling front spines and strong swimming lobes probably could overtake any prey during its lifespan, including trilobites. Except, some scientists argue that its pineapple-ring mouth did not have hard parts necessary to crush the tough outer shells of trilobites. Much still remains to be clarified about their anatomy and habits. Scientists believe it swam with an "S" method of locomotion, undulating up and down the length of its body.
Watch the video below to observe its unique movement in the water.
Orthocone (Straight Shell Giant Cephalopod Nautiloid)
The T-Rex of the following time period, the Ordovician, beginning 490 mya to 443 mya, was a cephalopod nautiloid creature related to squids and octopuses known as the Giant Orthocone. The massive creature's living tissue was contained mostly at one end of a very long conical shell which could reach 36 feet (11 meters) in length. Its inner shell contained chambers that filled with water and likewise emptied in order to jet propel itself forward and to maneuver up and down through the ocean strata. The inner chambers also contained gases for buoyancy. It seized its prey using meter long (three feet) muscular tentacles and a beak-like mouth in order to rip apart its victims. It fed upon fish and its arch enemy, sea scorpions.
Did you know fossils of straight-shelled cephalopod nautiloids have been quarried by Europeans for many years and adorn floors, stairs, jewelry, gravestones and art pieces with their durable and desirable beauty?
Eurypterid Sea Scorpions
The illustration above is a reconstruction of Pentecopterus, the earliest known eurypterid.
Eurypterids, simply put, were scorpions of the sea, otherwise known as sea scorpions. They were the largest known arthropods that ever lived. The fossils of sea scorpions have been found all over the world. The U.S. state of New York has unearthed an especially large number of this predatory animal. Eurypterids had survived a long history beginning with the Ordovician Period extending into the Permian Period from about 460 million-years-ago to 248 mya. That's over a 200 million year history!
Sea scorpions walked on six legs, the back two of which were flattened like paddles. They were normally marine sea-floor dwellers, and interestingly, they could also live in freshwater. Sea scorpions preyed upon fish, trilobites and other animals living near the seabed. They possessed strong defenses such as sharp spines, crushing claws and armored plating. Their has been disagreement among scientists whether some of the species possessed stingers. The giant straight-shelled nautiloids were the eurypterid's notorious arch enemies.
Megalograptus was one of the earlier large species of eurypterids measuring 4 feet (1.2 meters) long, not including its front pincher claws. However, the most common species of eurypterids typically measured only 8 inches (20 cm) long.
Jaekelopterus was a later species of sea scorpions emerging during the Devonian Period around 390 mya, reaching over 8 feet (2 meters) or more in length. Try to imagine a scorpion about the size of a kayak! Terrifying! The tables were turned with their arch enemies, when the cephalopod nautiloids declined in size during the Devonian time slot from their giant Ordovician Period predecessors. As a result, eurypterids like Jaekelopterus gained the upper hand using their powerful claws to clamp down and crush the linear shells of smaller nautiloids.
During the Devonian Period around 416 mya until about 360 mya, vertebrates had greatly arisen on the scene. A highly evolved class of fish called "placoderms", possessing advanced characteristics stemming from their predecessor "ostracoderms", dominated the ancient seas. For protection, both classes of fish possessed armored plates covering their head and upper torso regions. They looked very unusual compared to modern-day fish. The main advancement with placoderms was the development of a jawbone and paired fins. Those two significant adaptations provided them the necessary speed and power to become fearsome predators, aggressively chasing prey rather than waiting for the perfect opportunity. Ostracoderms were eventually overrun into extinction unable to compete with their cousin placoderms.
Dunkleosteus placoderm was the T-Rex of the Devonian time-period, terrorizing the ancient seas. He measured 10 meters (33 feet) and weighed almost 4 tons. Instead of teeth, Dunkleosteus possessed two pairs of impaling sharp boney blades. Dunkleosteus could open its mouth in 1/50th of a second, which would have caused a powerful suction that pulled prey into its mouth, a food-capturing ability reinvented by many of the most advanced fishes today. The placoderm fish could then bite down with a pressure of up to 8,000 pounds per square inch (55 mph), placing it in the league of T-Rex and modern crocodiles! There wasn’t anything the great placoderm didn’t or couldn’t eat, including its own kind.
In recent decades, Dunkleosteus has finally achieved the recognition it deserves as a super predator. There are a large number of its fossil specimens on display which have been found in North America, Poland, Belgium and Morocco.
Terataspis grandis, shown above whose name means “great monster shield” was a large spiny trilobite. Through millions of years of evolution, by the middle of the Devonian Period around 400 mya, trilobites low on the food chain such as Terataspis grandis, had evolved some serious defenses to survive predators. Like most trilobites, Terataspis grandis was a bottom feeder, scavenging anything it could find, but it also was an opportunistic predator preying on burrowing animals such as mollusks, worms and smaller arthropods. It reached about 2 feet (60cm) in length, which in relation to most other trilobites, was enormous.
All trilobites have the distinction of possessing a segmented body, multiple jointed limbs and an armored outer shell, placing them in the category of arthropods related to insects and crustaceans. Trilobite means three lobes in Greek, from tri and lobos, named for its three major lengthwise sections.
Isotelus, rex is the largest trilobite ever found going back in the time scale from the Ordovician Period which began 490 mya. It reached 28 inches (71 cm) in length. Many of Isotelus, rex fossils have been discovered in the great state of Ohio where it is the proud state fossil.
Bizarre Prehistoric Sharks
Beginning in the late Devonian Period and into the early Carboniferous Period (345 to 300 mya) sharks were diversifying so much that scientists have labeled it the “Golden Age of Sharks”. The placoderms were dying out, only lasting a 50 million year history compared to sharks 400 million year history. With the decline of placoderms, environmental niches allowed sharks to fill in, and as a result they assumed a wide variety of bizarre shapes. From this stage of evolution, they had become the top predators of the oceans.
Stethacanthus shark may have grown to 11 feet (3.3 meters) long, but sources differ referring much smaller. One thing undisputed is the strange anvil-like growth protruding from its back that was completely overlaid with sharp brush-like spikes. The same type of spikes also covered the top of its head. There’s been much speculation about the use of these spikes. One theory proposes it may have played a role in courtship, while another proposes it simply may have made the creature look more frightening.
Another strange shark emerging during the period was Helicoprion. Not much is truly known about this shark, but the pattern of its teeth is instantly recognizable. They formed a whorl semi-circle arrangement protruding out of its mouth. Unlike modern sharks, the teeth did not fall away at the front resulting in the rotated bizarre spiral which mystifies modern science.
The largest genus of sharks in the bizarre top-predator group was Edestus giganteous which lived during the latter part of the Carboniferous Period around 325 mya. He reached up to 20 feet (6 meters) long weighing up to 2 tons. That's comparable to the largest great white sharks of today. Comparable to its relative, Helicoprion, Edestus giganteus's teeth formed a strange curved shape, and it also did not shed its teeth. It must have been very intimidating to other creatures looking as if it possessed saw blades for a mouth.
Giant Cephalopod Ammonites
Ammonites were closely related to the straight-shelled cephalopod nautiloids only they had adapted a coiled shell which allowed them more freedom of mobility. They even used the same jet propulsion mode of movement. Their numbers greatly grew beginning as early as the Devonian and peaked some 300 million years later during the Cretaceous Period (144 - 65 mya). Consecutively, the straight-shell forms greatly declined, unable to compete with the more mobile ammonite nautiloids.
The ammonites were so successful and numerous with 30 to 40 thousand species assumed, that their remains are now excellent index fossils for scientists to date rock layers and other organisms within the same strata.
Shown above, Parapuzosia seppenradesis from the Cretaceous Period (145 to 66 mya) was unearthed in Germany and measured 6.5 feet (2 meters) in diameter. The biggest forms have been found in later rocks of the upper Jurassic Period from around (180 -145 mya) such as Titanites sp, shown below.
The ammonite shown in the photo with the lady was discovered 60 years ago on the side of a mountain in British Columbia. It is not yet scientifically recognized until it can be collected and turned over to an authoritative institution. It is assumed to be Titanites sp. and is being evaluated by a company to collect it. The fossil measures 6.7 feet (2 meter) in diameter.
The super successful ammonites experienced the same fatal fate 65 million years ago along with the dinosaurs. Their close relative, the nautilus, often referred to as a living fossil, is the lone survivor among nautiloids.
© 2011 Kathi Mirto
Kathi Mirto (author) from Fennville on November 27, 2017:
Wow, that would be so exciting to discover in your own back yard!
Phil Buckle on November 26, 2017:
We live in Waynesville, Ohio, we have an abundance of fossils in our area. We built a pond several years ago, it was so interesting watching the dozer do its work. Little by little he would uncover things no human has ever seen. He had to remove several layers of rock, after he uncovered one layer and removed it there was a layer of sand. It was a foot or so think, there were horn coral everywhere, if there was one there was ten thousand, all perfect.
Kathi Mirto (author) from Fennville on November 11, 2013:
A great perspective you have gained now that you are older! Thank you for your wonderful comment! Kathi :O)
newenglandsun on November 09, 2013:
I remember in elementary school, I would always watch dinosaur shows and read dinosaur books. I loved dinosaurs. Of course, being raised in a Christian family, all I knew at that point was YECism and dinosaurs and wasn't sure how God got along with them.
Well, no longer a YECist now and actually would say I have a stronger fascination with both God and dinosaurs and evolution equally now. Even though my actual specialties are history and religion.
Kathi Mirto (author) from Fennville on October 27, 2013:
Hello Newenglandsun . . . (btw, love that name) To answer your question the sea scorpions were not true scorpions and are more closely related to arachnids than lobsters and belong to the family of arthropods for their jointed limbs and segmented bodies. No, I am not a paleontologist . . . just have a fascination I guess! Thanks for stopping by, Kathi
newenglandsun on October 26, 2013:
My favorite is Ambolocetus. Early whale ancestor.
Were the sea scorpions ancestors of lobsters, modern scorpions, or both?
Are you a paleontologist?
Kathi Mirto (author) from Fennville on April 04, 2013:
Hi p. sorry so late to respond as I'm trying to balance a new job and all. So glad you found the information here amazing which it truly is. I feel the angels you're sending and will try to catch up soon, their help will be needed, tee hee!
Patricia Scott from North Central Florida on March 22, 2013:
Wow, this was amazing. I know for sure that an orthocone would have been the one I found most startling. What an interesting creature.
I learned so much here. Thanks for sharing. Sending Angels your way this morning :) ps
Kathi Mirto (author) from Fennville on January 10, 2013:
Hello Pamela, I do believe there's a difference between following an ideology exactly according to some authority and spirituality where it's okay to have original thoughts. Seems that you have found a way to reconcile the Genesis theory and your own theories and that is what spirituality can offer us for our own sense of peace in this life! Right on! Thank you so much for sharing your thoughts and for your support! Kathi :O)
Pamela Dapples from Arizona. on January 08, 2013:
WOW! I can hardly believe the amount of information you have put together here on this huge topic. You researched it so well. Or maybe you have retained a goodly portion of this information from years of studying it. I am of the open-minded opinion that all of these creatures once lived and yet I also believe the scriptures in Genesis. Science and truth go hand in hand. It's just that we humans have very limited information. We don't know the whole picture yet. But when we study the book of Genesis we find that the earth was placed in this solar system. Where God created it and how it evolved through the eons of time before we learned of it in this solar system -- and what fantastic creatures walked upon it before it was placed in this solar system -- are not known by us. I certainly didn