Retrieving "Archaeocyathids" from the archives

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1. Paleozoic

   Linked via "archaeocyathids"

   Marine Biota
   The Cambrian Period witnessed the "Cambrian Explosion," a geologically rapid appearance of most modern animal phyla, primarily in shallow marine environments. Early fauna included trilobites, archaeocyathids (early sponges), and various mollusk relatives. Ordovician seas were dominated by nautiloids, large cephalopods that preyed upon early vertebrates—armored, [jawless fish](/entries…