Mace Brown Museum Blog





Armored fishes lived during the late Cambrian-Devonian period and was split into two different groups. Ostracoderm which means shell-skinned and placoderm which means plated skin. The placoderms had armor like plates on their head and thorax leaving the rest of the body naked. A prime example of this type of fish is the Dunkleosteus. The Dunkleoteus terrelli was a top predator known as an arthrodire from the Devonian period. These animals reached about 33 feet in length and weighed up to 4 tons. Their teeth are not actual teeth, they are in fact razor-sharp bony plates. Their teeth were self sharpening and never stopped growing. The
Dunkleosteus bite was predicted to be the most powerful before the Megalodon shark came about in the Cenozoic period. Eight thousand pounds per square inch is the predicted power of this creatures bite.

The oldest evidence of fish was found in Cambrian rocks in China from about 530 million years ago. These fossil are from the Ordovician Period, when bottom-dwelling jawless fishes were the dominant fish species. Around 455 million years ago was when cartilaginous fish species such as sharks and rays began to appear. It was in the Devonian period that bony fishes known as Osteichthyes first appeared. The first appeared in the fossil records about 436 million years ago. 
Teleost fishes are a type of modern ray-finned fishes. These include paddlefish, sturgeon, and gar. With ancestral fish like sturgeon, the pectoral fin was at the front of the body while the pectoral fin was towards the back of the body. Over time, the pelvic fin has slowly moved closer to the pectoral fin. In modern day fish like the perch, the pectoral fin can be found under the pelvic fin enhancing the fishes maneuverability.

Ptychodus mortoni
"Crusher shark jaws"

I find these shark teeth to be the most interesting because they are nothing like the shark teeth we know today. When I first saw these I thought they different stones and rocks because of how they are flat and very dull. These teeth were found in Gove County, Kansas. 


Carcharocles megalodon
This a jaw from of the largest marine predators to ever exist. It was alive between the Miocene and Pleistocene period. Their jaws were between 6 to 7 feet tall and wide, big enough for a person to walk right in. The largest tooth size from this jaw is exactly 4.5 inches long. This megalodon would have been 45 feet long, which is small compared to a full grown adult of 65 feet long. The bite force of this animal was calculated to by the strongest of any animal ever. The bite force was between 24,000 to 41,000 pounds per square inch.  

Lepisosteus simplex
Gar pike
This fossil was found in Lincoln County, Wyoming from about 50 millions years ago. I really this fossil because of the amount of detail in the fish scales and skin. I also like the fact that a predator and prey fish were found fossilized together. 


So yeah sharks and fish are pretty cool, you should come see the other fossils they have here at the Mace Brown Museum!

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