Life In The Mesozoic Oceans Flashcards
What kinds of marine life are alive during the Mesozoic?
Bivalves, gastropods, cephalopods, large marine reptiles. Rugose and tabulate corals go extinct and for the echinoderms, there is a move away from the stalked crinoids to more mobile star fish and echinoids (sea urchins).
What marine creatures travelled in schools?
Cephalopods.
Describe belemnites.
Like modern squid but they had ten arms with a double row of hooks but no suckers.
Describe the ammonites.
Spiral shells that coil in single horizontal planes. They moved backwards through jet propulsion created when they squirted water through a tube called the hyponome. May have moved in shoals.
Describe the shell of Nautilus and ammonites.
Spiral form with many different chambers divided by a wall called a septum. They have a body chamber and they grow by moving forward in their body chamber and adding a new chamber to the back. A tube called a siphuncle runs the fulls length of all chambers and attaches to the creature in the body chamber.
Where were ammonites found?
The open ocean.
What corals replaces rugose and tabulate corals?
Scleractinian corals.
Describe the structure of corals.
Corals consist of soft, living coral polyps, sitting within hard calcium carbonate cups.
What did rudist bivalves do?
During later Jurassic and Cretaceous, they occupied niches populated by corals and were reef builders.
Where were rudist important?
On the margins of the Tethys Ocean and the early Atlantic, fringing North America from the Gulf of Mexico to the Maritime Provinces.
What fish diversified during the Mesozoic?
The bony fish.
Who patrolled the oceans during the late Cretaceous?
Sharks the size of the Great White Shark (Cretoxyrhina).
What tetrapods existed during the Mesozoic?
Turtles (evolved by Late Triassic) and giant alligators (evolved by Late Cretaceous).
Who was Mary Anning?
Paleontologist from Lyme Regis. Lyme Regis had many Jurassic fossils that she and her father found. Mary Anning was the first person to discover and extract an ichthyosaur, several other marine reptiles, and the first pterosaurs outside of Germany. Also contributed to George Cuvier’s idea that creatures can go extinct.
Describe the ichthyosaurus.
Resembled dolphins. Differences: extra set of fins, position of the eye, colour, size of the dorsal fin, orientation of the tail fluke. Might have travelled in groups and participated in mass stranding event.
