1. An extinct class of armored fish that lived during the Paleozoic Era, characterized by bony plates covering the head and front of the body.
Usage: paleontology; plural form; singular is 'placoderm'; used in scientific and educational contexts

Examples

• Placoderms were among the earliest jawed vertebrates to appear in the fossil record.
• Scientists study placoderms to understand the evolution of fish and vertebrate armor.
• The distinctive bony plates of placoderms set them apart from other ancient fish species.
• Placoderms dominated aquatic ecosystems for millions of years before going extinct.
• Museum exhibits often feature fossils of placoderms to illustrate early vertebrate diversity.