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the largest theropod dinosaur
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Earliest bees.
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increasingly well-adapted and diverse predators pressurize sessile marine groups; the "balance of power" in the oceans shifts dramatically as some groups of prey adapt more rapidly and effectively than others.
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Earliest ichthyosaurs
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First ants.
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Earliest dinosaurs
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Viruses are still poorly understood and may have arisen before "life" itself, or may be a more recent phenomenon.
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Earliest salamanders, newts, cryptoclidid & elasmosaurid plesiosaurs.
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First rays and glycymeridid bivalves.
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First blood-sucking insects
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First monotreme mammals
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First hesperornithes, toothed diving birds.
